Laser welded assemblies

Abstract

A system includes a laser welder configured to weld a first steel workpiece to a second workpiece at an interface between them. The workpieces may have similar or dissimilar compositions and / or thicknesses. A filler wire may be used to fill a gap at the interface and / or provide a weld joint composition that accounts for the intrusion of aluminum coating from the workpiece(s) into the weld joint. The laser welder's laser beam may be laterally offset from the interface toward one of the workpieces (e.g., a thicker or stronger of the workpieces).

Description

LASER WELDED ASSEMBLIESCROSS REFERENCE

[0001] This application claims the benefit of priority from: U.S. Provisional Patent Application No. 63 / 609,053, filed December 12, 2023, titled “Laser Welded Blanks”; U.S. Provisional Patent Application No. 63 / 645,980, filed May 13, 2024, titled “Laser Welded Blanks”; and U.S. Provisional Patent Application No. 63 / 643,947, filed May 8, 2024, titled “Method of Tracking A Blank Edge For Laser Cutting.” The entire contents of each of these applications are hereby incorporated by reference herein in their entirety.FIELD

[0002] The present patent application relates to a system and a method for laser welding steel sheets such as aluminum coated steel sheets.BACKGROUND

[0003] Boron steel is often used in the automotive industry due to its ability to form a fully martensitic microstructure, which results in a high strength material. Despite low formability levels, boron steel can be hot stamped to increase formability, and create strong, formed structures such as a car door frame, through a hot stamping process. However, the boron steel alone tends to form an oxide layer at the surface during heat treatment. This oxide layer may create wear on the stamping die and prevent an adhesive painting process. Therefore, boron steel is often coated with an aluminum based coating.

[0004] The aluminum based coating on boron steel provides a barrier to prevent oxidization / scaling during the austenitization process and also allows the aluminum to react with iron within the aluminum based coating. The aluminum based coating has a high melting point that is capable of withstanding the hot stamping process.

[0005] Hot stamping steel is commonly paired with laser blank welding due to the versatility of the process. Several blanks of different thicknesses and material can be joined together by laser welding and then hot stamped into one formed component. This has many advantages such as the ability to have some parts with structural strength and some with crash energy absorption capabilities, different material thicknesses to save on weight and costs, and better nesting of the blanks to reduce coil scrap rates.

[0006] The problem is that the aluminum based coating can negatively affect the laser welding process. During welding, the aluminum has a tendency to mix with the iron and form a brittle intermetallic, which can cause cracking along the weld. The aluminum based coating on the high strength, hot stamping steel (e.g., Usibor®) pollutes the weld pool (a.k.a. melt pool)during laser welding. This iron-aluminum intermetallic adversely affects the weld’s hardenability. This also does not meet the mechanical property requirements (tensile strength, hardness, etc.) for a hot stamped component.

[0007] In a prior art method of ArcelorMittal Tailored Blanks (AMTB), the aluminum based coating is removed using an ablation procedure (e.g., by an ablation laser). The highly accurate ablation process can remove the majority of the aluminum based coating, but leaves the intermetallic layer of Al-Fe. The uncoated blanks (or partially uncoated blanks) are then laser welded together.

[0008] In another prior art method, powder (supplied by a power feed nozzle) or filler wire (supplied by a filler wire feeding system) is added to bind the aluminum based coating on the base metal, during the laser welding procedure, for example as shown in U.S. Patent Application Publication No. 2021 / 0078106, the entire contents of which are incorporated herein by reference.

[0009] The present patent application provides improvements to systems and methods for laser welding steel blanks.SUMMARY

[0010] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method may comprise: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface to melt a portion of at least one of the steel workpieces to form a melt pool that solidifies to form a weld joint between the workpieces, wherein the laser beam is laterally offset from a center of the interface by an average offset distance Y’ during said moving, and wherein Y’ is at least 0.1 mm; and feeding a filler wire into the melt pool during said moving.

[0011] One or more of these embodiments further comprises oscillating the laser beam laterally during said moving such that an instantaneous lateral offset varies as the laser beam moves along the interface.

[0012] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method comprises: arranging the first and second workpieces relative to each other such that an interface is formed between edges of the first and second workpieces, wherein the interface has first and second ends, wherein the edge of one of the workpieces diverges from the edge of the other of theworkpieces at the first end such that a first vertex is formed between the edges at the first end, and wherein the edge of one of the workpieces diverges from the edge of the other of the workpieces at the second end such that a second vertex is formed between the edges at the second end; detecting a location of the first and second vertexes using a camera; and moving a laser beam along the interface from the first vertex to the second vertex based on the detected locations of the first and second vertexes to melt a portion of at least one of the steel workpiece and form a weld joint between the steel workpieces.

[0013] According to one or more of these embodiments, a first notch is formed in at least one of the workpieces at the first end of the interface such that the first vertex is at least partially defined by the first notch, and a second notch is formed in at least one of the workpieces at the second end of the interface such that the second vertex is at least partially defined by the second notch.

[0014] According to one or more of these embodiments, portions of the workpieces at the first end are misaligned with each other, and portions of the workpieces at the second ends are misaligned with each other such that the first vertex is defined where one of the workpieces protrudes past the other of the workpieces, and the second vertex is defined where one of the workpieces protrudes past the other of the workpieces.

[0015] One or more non-limiting embodiments provides a method for forming a weld assembly. The method comprises laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld j oint between the first and second steel workpieces. The first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint. The first workpiece comprises iron and 0.040% < C < 0.100%. The second workpiece comprises iron and 0.10% < C < 0.5%. The filler wire comprises iron and at least 10% Ni.

[0016] According to one or more of these embodiments, the filler wire comprises: 0.0% < C < 0.03% and 10% < Cr < 40%.

[0017] According to one or more of these embodiments, the filler wire comprises: 18% < Cr < 20%; 11% < Ni < 14%; 2% < Mo < 3%; 1% < Mn < 2.5%; and 0.3% < Si < 0.65%.

[0018] According to one or more of these embodiments, the filler wire comprises: 0.18%<C<0.25% and 10% < Cr < 40%, and the weld joint comprises 0.15% < C < 0.25%.

[0019] According to one or more of these embodiments, the filler wire comprises: 15%<Cr<17%; 34%<Ni<37%; 0%<Mo<0.75%; l%<Mn<2.5%; and 0%<Cu<0.75%.

[0020] According to one or more of these embodiments, the first workpiece comprises 0.80%< Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%, and the second workpiece comprises 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%.

[0021] According to one or more of these embodiments, the weld joint comprises ferrite.

[0022] According to one or more of these embodiments, the weld joint comprises less than5% ferrite.

[0023] According to one or more of these embodiments, a carbon concentration of the weld joint is lower than a carbon concentration of the second workpiece.

[0024] According to one or more of these embodiments, a carbon concentration of the filler wire is lower than a carbon concentration of the second workpiece.

[0025] One or more of embodiments provides a laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein the first workpiece comprises iron and 0.040% < C < 0.100%, wherein the second workpiece comprises iron and 0.10% < C < 0.5%, and wherein a bulk nickel concentration in the weld joint is at least 2.0%.

[0026] One or more non-limiting embodiments provides a method for forming a weld assembly. The method comprises laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld j oint between the first and second steel workpieces. The first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint. The filler wire comprises iron and at least 10% Ni. The weld joint has a ferrite concentration Ferri tewr, and 0.0% < Ferri tewr < 5.0%.

[0027] According to one or more of these embodiments, the first workpiece comprises iron and 0.040% < C < 0.100%; and the second workpiece comprises iron and 0.10% < C < 0.5%.

[0028] According to one or more of these embodiments, the filler wire comprises: 0.0% < C < 0.03% and 10% < Cr < 40%.

[0029] According to one or more of these embodiments, the filler wire comprises: 18% < Cr< 20%; 11% < Ni < 14%; 2% < Mo < 3%; 1% < Mn < 2.5%; and 0.3% < Si < 0.65%.

[0030] According to one or more of these embodiments, the filler wire comprises: 0.18%<C<0.25% and 10% < Cr < 40%.

[0031] According to one or more of these embodiments, the filler wire comprises: 15% < Cr < 17%; 34% < Ni <37%; 0%< Mo <0.75%; 1%< Mn <2.5%; and 0%< Cu <0.75%.

[0032] One or more non-limiting embodiments provides a laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein the weld joint has a ferrite concentration Ferritewr, and wherein 0.0% < Ferritewr < 5.0%.

[0033] According to one or more of these embodiments, an aluminum concentration ALwr in the weld joint is at least 0.5%.

[0034] One or more non-limiting embodiments provides a method for forming a weld assembly. The method comprises laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld j oint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the filler wire comprises iron and at least 10% Ni; the weld joint has a bulk aluminum concentration of Alwr; and a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10 x ALwr.

[0035] According to one or more of these embodiments, 0.5% < Alwr < 2.5%.

[0036] According to one or more of these embodiments, the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 5 x Alwr.

[0037] According to one or more of these embodiments, the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 4 x Alwr.

[0038] According to one or more of these embodiments, the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 3 x Alwr.

[0039] According to one or more of these embodiments, the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 2 x Alwr.

[0040] According to one or more of these embodiments, the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 5%, 4%, and / or 3%

[0041] According to one or more of these embodiments, a local aluminum concentration within any 0.05 mm x 0.05 mm area within any cross section within the weld joint, as measured using EDX, is less than 5 x Alwr.

[0042] According to one or more of these embodiments, an aluminum concentration within any 0.05 mm x 0.05 mm area within any cross section within the weld joint, as measured using EDX, is less than 5%.

[0043] According to one or more of these embodiments, the first workpiece comprises iron and 0.040% < C < 0.100%; and the second workpiece comprises iron and 0.10% < C < 0.5%.

[0044] According to one or more of these embodiments, the first workpiece comprises: 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%, and the second workpiece comprises: 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%.

[0045] According to one or more of these embodiments, the filler wire comprises 0-0.03% C, 18-20% Cr, 11-14% Ni, 2-3% Mo, 1-2.5% Mn, and 0.3-0.65% Si.

[0046] According to one or more of these embodiments, the filler wire comprises 0.18-0.25% C, 15.0-17.0% Cr, 0-0.75% Cu, 1.0-2.5% Mn, 0-0.75% Mo, 34.0-37.0% Ni, 0-0.03% P, 0-0.03% S, and 0.30-0.65% Si.

[0047] One or more embodiments provide a laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein the weld joint has a bulk aluminum concentration of Alwr, and wherein a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10 x ALwr.

[0048] One or more non-limiting embodiments provides a method for forming a weld assembly. The method comprises laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld j oint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the filler wire comprises iron and at least 10% Ni; the weld joint has a bulk aluminum concentration Alwr of less than 2.5%; and a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10%.

[0049] According to one or more of these embodiments, the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 5%, 4%, 3%, and / or 2.5%.

[0050] According to one or more of these embodiments, 0.5% < Alwr < 2.5%.

[0051] One or more non-limiting embodiments provides a laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein the weld joint has a bulk aluminum concentration of Alwr; wherein 0.5% < Alwr < 2.5%; and wherein a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10%.

[0052] One or more non-limiting embodiments provides a method for forming a weld assembly. The method comprises laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld j oint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the first workpiece comprises iron and 0.040% < C < 0.100%, 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%; the second workpiece comprises iron and 0.10% < C < 0.5%, 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo <20%; the filler wire comprises iron and at least 10% Ni; and the weld joint is such that after hot stamping and cooling, a maximum hardness variation within at least one cross section of the weld joint is greater than 20% of an average hardness of the weld joint within the cross section.

[0053] According to one or more of these embodiments, the maximum hardness variation is greater than 25% of the average hardness.

[0054] According to one or more of these embodiments, the filler wire comprises 10-40% Cr.

[0055] One or more non-limiting embodiments provides a laser welded assembly comprising: a first steel workpiece comprising iron and 0.040% < C < 0.100%, 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% <Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% <Ni < 0.100%, 0.0%< Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%; and a second steel workpiece welded to the first steel workpiece along a weld joint, the second workpiece comprising iron and 0.10% < C < 0.5%, 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, and wherein the weld joint is such that after hot stamping and cooling, a maximum hardness variation within at least one cross section of the weld joint is greater than 20% of an average hardness of the weld joint within the cross section.

[0056] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method comprises: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface at a welding speed of between 80 and 120 mm / s to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving at a filler wire feed rate of at least 10 mm3 / s, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint, and wherein the filler wire comprises iron and at least 10% Ni.

[0057] According to one or more of these embodiments, the filler wire comprises 10% < Cr< 40%.

[0058] According to one or more of these embodiments, the first workpiece comprises iron and 0.040% < C < 0.100%; the second workpiece comprises iron and 0.10% < C < 0.5%; and the filler wire feed rate is between 10 and 40 mm3 / s.

[0059] According to one or more of these embodiments, the first workpiece comprises: 0.80%< Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%, and the second workpiece comprises: 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%.

[0060] According to one or more of these embodiments, the first and second workpieces each comprise iron and 0.10% < C < 0.5%, and wherein the filler wire feed rate is between 30 and 65 mm3 / s.

[0061] According to one or more of these embodiments, the first and second steel workpieces each comprise: 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti< 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0%< B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%;

[0062] According to one or more of these embodiments, a power output of the laser beam is between 4 and 10 kw.

[0063] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method comprises: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface at a welding speed to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving at a volumetric filler wire feed rate in mm3 / s, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint, wherein the filler wire comprises iron and at least 10% Ni, wherein an average gap width is defined along the interface, wherein a thinner of the workpieces has a thickness t, wherein a welding gap rate in mm3 / s = (average gap width in mm) x (thickness t) x (welding speed in mm / s), and wherein (volumetric filler wire feed rate) > (welding gap rate).

[0064] According to one or more of these embodiments, the filler wire comprises 10% < Cr< 40%.

[0065] According to one or more of these embodiments: (volumetric filler wire feed rate) > 1.1 x (welding gap rate).

[0066] According to one or more of these embodiments, the volumetric filler wire feed rate exceeds the welding gap rate by at least 1 mm3 / s.

[0067] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method comprises: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface at a welding speed to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving at a volumetric filler wire feed rate in mm3 / s, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint, wherein the filler wire comprises iron and at least 10% Ni, wherein gap width is defined between the workpieces along the interface, wherein a thinner of the workpieces has a thickness t, wherein an instantaneous welding gap rate in mm3 / s = (gap width in mm at a location of the laser beam along the interface) x (thickness t) x (welding speed in mm / s), and wherein an instantaneous volumetric filler wire feed rate exceeds the instantaneous welding gap rate throughout said moving and feeding.

[0068] According to one or more of these embodiments, the filler wire comprises 10% < Cr< 40%.

[0069] According to one or more of these embodiments, throughout said moving and feeding:(instantaneous volumetric filler wire feed rate) > 1.1 x (instantaneous welding gap rate).

[0070] According to one or more of these embodiments, throughout said moving and feeding, the instantaneous volumetric filler wire feed rate exceeds the instantaneous welding gap rate by at least 1 mm3 / s.

[0071] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method comprises: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weldjoint between the steel workpieces; feeding a filler wire into the melt pool at a feed rate during said moving; and varying the feed rate of the filler wire during said moving.

[0072] According to one or more of these embodiments, the method further comprises detecting a size of a gap between the workpieces at multiple locations along the interface, wherein said varying of the feed rate comprises varying the feed rate based on variations in the detected gap.

[0073] According to one or more of these embodiments, the method further comprises detecting a size of a gap between the workpieces at multiple locations along the interface, wherein said varying comprises increasing the feed rate where the gap widens and reducing the feed rate where the gap narrows.

[0074] One or more non-limiting embodiments provides a method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly. The method comprises: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface to melt a portion of at least one of the steel workpieces to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving, wherein, in a cross-section perpendicular to the weld joint, the weld joint has a top surface overfill OTOP or a bottom surface overfill OBOTTOM, wherein a thinner of the steel workpieces has a thickness t, and wherein at least one of OTOP and OBOTTOM is equal to or greater than 0. It.

[0075] According to one or more of these embodiments, 0. It < OTOP.

[0076] According to one or more of these embodiments, at least one of OTOP and OBOTTOM is equal to or greater than 0.15t.

[0077] According to one or more of these embodiments, the method further comprises stamping the weld assembly between first and second dies, wherein at least one of the dies includes a recess to accommodate an overfill of the weld joint.

[0078] One or more non-limiting embodiments provides a laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein, in a cross-section perpendicular to the weld joint, the weld joint has a top surface overfill OTOP or a bottom surface overfill OBOTTOM, wherein athinner of the steel workpieces has a thickness t, and wherein at least one of OTOP and OBOTTOM is equal to or greater than 0. It.

[0079] According to one or more of these embodiments, 0.15t < (OTOP + OBOTTOM).

[0080] According to one or more of these embodiments, 0.20t < (OTOP + OBOTTOM).

[0081] According to one or more of these embodiments, 0.25t < (OTOP + OBOTTOM).

[0082] According to one or more of these embodiments, the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating melting into the melt pool and forming part of the weld joint, and the filler wire comprises iron and at least 10% Ni.

[0083] One or more of these embodiments further comprises heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

[0084] One or more of these and / or other aspects of various embodiments of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one or more embodiments, the structural components illustrated herein are drawn to scale. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0085] All closed-ended (e.g., between A and B) and open-ended (greater than C) ranges of values disclosed herein explicitly include all ranges that fall within or nest within such ranges. For example, a disclosed range of 1-10 is understood as also disclosing, among other ranges, 2-10, 1-9, 3-9, etc. Similarly, where multiple parameters (e.g., parameter C, parameter D) are separately disclosed as having ranges, the embodiments disclosed herein explicitly include embodiments that combine any value within the disclosed range of one parameter (e.g., parameter C) with any value within the disclosed range of any other parameter (e.g., parameter D).

[0086] For example, where exemplary chemical compositions for a material (e.g., the workpieces 106, 108, the filler wire 116) provide alternative ranges for different elements, this should be understood to mean that non-limiting embodiments expressly include every combination of different ranges for different elements. For example, if a chemical composition is disclosed to have a carbon content of 0<C<l or 1< C<2 and a Mn content of 3<Mn<4 or 4<Mn<5, that disclosure is an explicit disclosure of each of the following compositions: i) 0<C<l and 3<Mn<4; ii) 0<C<l and 4<Mn<5; iii) 1< C<2 and 3<Mn<4; and iv) 1< C<2 and 4<Mn<5.

[0087] Unless otherwise specifically stated, all chemical composition articulations (e.g., of the workpieces 106, 108, of the filler wire 116, of the weld joint 114) are weight based. For example, 0.10% carbon means 0.10 weight % carbon.

[0088] Unless otherwise specifically stated, all chemical concentration articulations refer to the average / mean concentration. For example, a weld joint 114 with a 0.16% carbon concentration means that the average / bulk carbon concentration over the entire weld joint is 0.16% carbon.BRIEF DESCRIPTION OF THE DRAWINGS

[0089] For a better understanding of various embodiments as well as other objects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:

[0090] FIGS. 1, 2, 3, 3 A, show one or more systems in which a filler wire having a composition including nickel is used, during laser welding procedure, to bind an aluminum based coating on the steel workpieces in accordance with various embodiments of the present patent application;

[0091] FIGS. 4 and 4 A show filler wire feeds in accordance with various embodiments of the present patent application;

[0092] FIG. 5 shows a wire feed nozzle and a welding laser in accordance with various embodiments of the present patent application;

[0093] FIG. 6 shows a system in which a filler wire having a composition of nickel is used, during a laser welding procedure, to bind the aluminum based coating on the workpieces,wherein the system is at a weld start position, in accordance with various embodiments of the present patent application;

[0094] FIG. 7 shows a system in which a filler wire having a composition of nickel and is used, during a laser welding procedure, to bind the aluminum based coating on the workpieces, wherein the system is at a weld end position, in accordance with various embodiments of the present patent application;

[0095] FIGS. 8, 8 A and 9 show a system in which a filler wire having a composition of nickel is used, during a laser welding procedure, to bind the aluminum based coating on the workpieces in accordance with various embodiments of the present patent application;

[0096] FIG. 10 is a diagrammatic view of a laser welder according to one or more embodiments;

[0097] FIGS. 11A-D are cross-sectional views of shaped laser beams or beam spots according to various embodiments;

[0098] FIG. 12 is a side view of a weld joint according to various embodiments;

[0099] FIGS. 13-14 are diagrammatic side views of a laser ablation process according to various embodiments;

[0100] FIGS. 15-16 are diagrammatic top views of workpieces arranged adjacent to each other in preparation for laser welding along their mutual interface;

[0101] FIG. 17 is a diagrammatic front view of a laser welder in an offset position relative to the workpieces being laser welded together;

[0102] FIGS. 18-19 are a diagrammatic front views of welded blanks according to various embodiments;

[0103] FIG. 20 is an SEM scan of a cross-section of a weld joint formed using a welding laser beam that was centered in the interface between the workpieces; and

[0104] FIG. 21 is an SEM scan of a cross-section of a weld joint formed using a welding laser beam that was laterally offset from a center of the interface between the workpieces during the welding process.DETAILED DESCRIPTION

[0105] FIGS. 1-9 show a system 100 that includes a laser welder 102 and a filler wire feed 104. In one or more embodiments, the laser welder 102 is configured to weld a first workpiece 106 to a second workpiece 108 (and optionally additional workpieces, e.g., to form a door ring) to form a laser welded assembly 110. In one or more embodiments, the workpieces 106, 108are positioned together to form an interface 112 therebetween and a weld joint 114 is formed by the laser welder 102 between the workpieces 106, 108 along the interface 112. In one or more embodiments, the filler wire feed 104 is configured to feed a filler wire 116 to the interface 112 when the workpieces 106, 108 are being welded to each other (i.e., by the laser welder 102) to form the welded assembly / blank 110.

[0106] In one or more embodiments, the system 100 includes a controller and / or one or more processors that are configured to control components of the system 100. In one or more embodiments, the one or more processors are configured to control the movement of the workpieces 106, 108 during the laser weld procedure. In one or more embodiments, the movement of the workpieces 106, 108 is achieved through movement of a worktable. In one or more embodiments, as discussed above, the one or more processors are configured to control the movement and / or the operation of the laser welder 102 and its produced laser beam 120 relative to the interface 112 during the laser weld procedure (e.g., by moving the workpieces 106, 108, the welding head of the laser welder 102, and / or the output beam 120 in the X and / or Y directions relative to the other components). In one or more embodiments, the one or more processors are configured to control the operation of the filler wire feed 104 during the laser weld procedure. In one or more embodiments, the one or more processors is / are configured to control the movement of the laser beam 120 across the surfaces of the workpieces 106, 108 in the X or X and Y directions. In one or more embodiments, the one or more processors is / are configured to control the shape of the laser beam 120 so as to vary the laser beam 120 shape over time during the welding process. In one or more embodiments, the one or more processors is / are configured to control the movement of the filler wire 116 across the surfaces of the workpieces 106, 108.

[0107] In various embodiments, the laser weld procedure is performed to weld a high strength steel (e.g., Usibor®) workpiece to a high strength steel (e.g., Usibor®) workpiece.

[0108] In other embodiments, the laser weld procedure is performed to weld a high strength steel (e.g., Usibor®) workpiece to a low strength steel (e.g., Ductibor®) workpiece.

[0109] In one or more embodiments, the filler wire 116 is stored on a filler wire spool 206, which is rotatably mounted in the filler wire feed 104. In one or more embodiments, the filler wire 116 is guided by or passes through one or more wire feed cables / tubings 202 positioned between the filler wire spool 206 and a wire feed nozzle 210. In one or more embodiments, the filler wire 116 then exits through the wire feed nozzle 210. In one or more embodiments, the filler wire feed 104 includes drive rollers (e.g., electrically powered) that are configured tomove the filler wire 116 through the one or more wire feed cables / tubings 202 and the wire feed nozzle 210 at a speed controlled by the controller and / or processors. In one or more embodiments, all the components of the filler wire feed 104 are made of material that is configured to withstand high weld temperatures.

[0110] In one or more embodiments, a wire feeder 208, shown in FIG. 3, is a master wire feed drive. In one or more embodiments, the filler wire feed box 204, shown in FIG. 3, is a slave wire feed drive. In one or more embodiments, the master wire feed drive 208 and the slave wire feed drive 204, both shown in FIG. 3, are servo-motor wire feed drives. In one or more embodiments, the slave wire feed drive 204 is configured to pull the wire off the filler wire spool 206 and feed the filler wire 116 toward the master wire feed drive 208. In one or more embodiments, the master wire feed drive 208 is configured to control the speed at which the filler wire 116 is fed into the process. In one or more embodiments, both the servo-motor wire feed drives (i.e., the master wire feed drive 208 and the slave wire feed drive 204 as shown in FIG. 3) are controlled by an E-Box (not shown in the figures). In one or more embodiments, the E-box is configured to receive wire feed commands from a cell control (e.g., PLC or robot) and coordinate the two drives 204, 208 to deliver the commanded wire rate. In one or more embodiments, the part names for the master wire feed drive 208 and the slave wire feed drive 204 (shown in FIG. 3) are model designations for an Abicor-Binzel wire feed system. In one or more embodiments, other equivalent and interchangeable systems made by different manufacturers may be used for the master wire feed drive 208 and the slave wire feed drive 204 (as shown in FIG. 3). In one or more embodiments, the filler wire 116 can also be stored on a filler wire barrel or other storage systems as would be appreciated by one skilled in the art. In one or more embodiments, the filler wire barrels, as opposed to filler wire spools, are used as these filler wire barrels last longer.A. STEEL WORKPIECES

[0111] In one or more embodiments, each of the workpiece 106 and the at least one additional workpiece 108 is formed from a steel material. In one or more embodiments, each of the workpieces 106, 108 may be referred to as base metal.1. Workpiece 106, 108 Thicknesses

[0112] The thickness of one of the steel workpieces 106, 108 may be the same as the thickness of the other of the steel workpieces 106, 108. The thickness of one of the steel workpieces 106, 108 may be different from the thickness of the other of the steel workpieces 106, 108.

[0113] In one or more embodiments, the workpieces 106, 108 have thicknesses that are less than 1.8 mm. In one or more embodiments, the workpieces 106, 108 have the same thickness. In one or more embodiments, the workpieces 106, 108 have stepped joints. In one or more embodiments, the steel workpieces 106, 108 have a range of thickness from a minimum of 0.5 mm to a maximum of 5.0 mm, with a maximum thickness ratio of 5: 1, 4: 1, 3: 1, and / or 2: 1. In one or more embodiments, the steel workpieces 106, 108 have a step thickness of less than 0.40 mm. In one or more embodiments, the step thickness difference or jump in thickness is less than 0.19 mm or greater than 0.41 mm.

[0114] The first steel workpiece 106 may have a first thickness and the second steel workpiece 108 may have a second thickness. According to various non-limiting embodiments, a difference in thicknesses between the workpieces 106, 108 is (a) at least 0.0, 0.1, 0.2, 0.3, O.4., 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4,2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 4.0, 4.5, and / or 5.0 mm, (b) less than or equal to 5.0, 4.5, 4.0, 3.5, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4,1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and / or 0.1 mm, and / or (c) between any two such values (e.g., 0.0-5.0 mm, 0.2-0.5 mm, 0.1-2.5 mm, 0.2-1.5 mm, etc.).

[0115] According to one or more embodiments, the thickness of the first and / or second workpiece 106, 108 is (a) at least 0.1, 0.2, 0.3, O.4., 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4,1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 4.0,4.5, and / or 5.0 mm thick, (b) less than or equal to 5.0, 4.5, 4.0, 3.5, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5,2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, and / or 0.2 mm, and / or (c) between any two such values (e.g., between 0.1 and 5.0 mm, between 0.5 and 4.0 mm, between 0.8 and 3.0 mm, between 1.0 and 2.5 mm, etc.).

[0116] In various embodiments, a deviation in the thickness between the two steel workpieces 106, 108 is 1.3 mm, for example, the thickness of one of the steel workpieces 106, 108 is 1.2 mm and the thickness of the other of the steel workpieces 106, 108 is 2.5 mm. In other embodiments, deviation in the thickness between the two steel workpieces 106, 108 is 0.7 mm, for example, the thickness of one of the steel workpieces 106, 108 is 1.9 mm and the thickness of the other of the steel workpieces 106, 108 is 2.5 mm.

[0117] According to various embodiments, a thickness of one of the workpieces 106, 108 is (a) at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, and / or 190 % thicker than the other workpiece 106, 108, (b) less than or equal to 200, 190, 280, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 75, 70, 65, 60, 55,50, 45, 40, 35, 30, 25, 20, 15, 10, and / or 5 % thicker than the other workpiece 106, 108, and / or (c) between any two such values (e.g., one of the workpieces 106, 108 is between 5 and 200 % thicker than the other workpiece 106, 108).

[0118] The thickness of the thicker of the steel workpieces 106, 108 may be reduced (e.g., via some form of machining) at its edge portions to be welded to match with the thickness of the thinner steel workpiece 106, 108 so that both the different thickness steel workpieces 106, 108 have the same thickness at their weld interface 112. The thickness of the thicker of the steel workpieces 106, 108 may be maintained the same (i.e., without performing any machining) at its edge portions so that there may be a stepped configuration between the edge of the thicker steel workpiece 106, 108 and the thinner edge of the thinner steel workpiece 106, 108 at the interface 112 where the weld 114 may be formed. The stepped configuration at the interface 112 between the two different thickness workpieces 106, 108 may allow for different gauges and may also prevent the overfill of the weld.

[0119] The thickness of the two workpieces 106 and 108 may be commonly specified by a traditional, non-linear measure known as its gauge. For example, the larger the gauge number, the thinner the workpiece is. The gauge of the two workpieces 106 and 108 that are being welded to each other may be the same. That is, the welded assembly including the two workpieces 106 and 108 may have a single gauge. The gauge of the two workpieces 106 and 108 that are being welded to each other may be different. That is, the welded assembly including the two workpieces 106 and 108 may have two different gauges.

[0120] The thickness of at least one of the steel workpieces 106, 108 that is used for body in white components may be (a) at least 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, and / or 1.8 mm, (b) less than or equal to 3.5, 3.0, 2.5, 2.0, 1.8, and / or 1.5 mm, and / or (c) between any two such values (e.g., 0.5-3.0 mm, 0.8-2.5 mm, 1.2-2 mm). According to various embodiments, the thickness of at least one of the steel workpieces 106, 108 that is used for a B-pillar may be in the range between 1.5 mm and 2 mm. The thickness of at least one of the steel workpieces 106, 108 may include the thickness of only the respective steel workpieces 106, 108. The thickness of at least one of the steel workpieces 106, 108 may include the thickness of the respective steel workpieces 106, 108 and their coatings. The thickness of the steel workpieces disclosed here and above are the thickness of the steel workpieces that may undergo a hot stamping procedure and may form a hot stamped material / component. Unless otherwise specifically stated, workpiece 106, 108 thicknesses discussed herein do not include a thickness of any coating onthe workpiece 106, 108, such that the thickness of the workpiece 106, 108 means the thickness of the base metal of the workpiece 106, 108 not including the thickness of any coating thereon.

[0121] In one example, a 1.4 mm thick high strength steel workpiece 106, 108 is welded to a 1.9 mm thick high strength steel workpiece 106, 108.

[0122] One of the steel workpieces 106, 108 may have varying thickness. For example, a tailor rolled blank steel workpiece may have varying thicknesses. The tailor rolled blank may generally be formed when the steel sheet goes through a mill in which rolls squeeze the material of the steel sheet to produce a blank / workpiece 106, 108 with varying thickness. For example, for a B-pillar, the tailor roller blank may have a thickness of 1.5 mm in some regions of the B- pillar and may have a thickness of 2 mm in other regions (e.g., in and around the crash zone) of the B-pillar. The tailor rolled blank may enable homogenous transition between these varying thickness regions of the tailor rolled blank. One of the steel workpieces 106, 108 may have thinner / smaller thicknesses at the edges and may have a normal sheet thickness in the middle portion. One of the steel workpieces 106, 108 may have thicker / larger thicknesses at the edges and may have a normal sheet thickness in the middle portion. One of the steel workpieces 106, 108 may have normal sheet thickness at the edges and may have thicker or thinner thickness in the middle portion. The laser welding may be performed in the middle portion having normal sheet thickness. The laser welding may be performed in the other portions having other thicknesses.

[0123] According to one or more embodiments, an edge to be welded of the thicker of the workpieces 106, 108 may be tapered / cambered / chamfered to have a thickness at the edge that is closer to a thickness of the thinner of the workpieces 106, 108.2. Workpiece 106, 108 Composition

[0124] In one or more embodiments, each of the workpieces 106, 108 is formed from a steel alloy material. In one or more embodiments, one or both of the workpieces 106, 108 are formed from boron steel. In one or more embodiments, one or both of the workpieces 106, 108 are formed from manganese boron steel. In one or more embodiments, the workpiece 106 is formed from a different steel grade, strength, and / or thickness than the workpiece 108.

[0125] Boron may be added, in the chemical composition of the steel in at least one of the steel workpieces 106, 108 for its effect on hardenability. Chromium, manganese, and carbon may also be added, in the chemical composition of the steel in at least one of the steel workpieces 106, 108 for its effect on hardenability.

[0126] According to various embodiments, the workpieces 106, 108 may have the same, similar, or dissimilar properties (e.g., material grade, composition, hardness, hardenability, strength). For example, one of the workpieces 106, 108 may have a relatively higher strength and / or hardenability than the other workpiece 106, 108.

[0127] As explained below, one workpiece 106, 108 (hereinafter referenced as a “high strength” steel workpiece 106, 108) may have a relatively higher strength than the other workpiece 106, 108 (herein after referenced as a “low strength” steel workpiece 106, 108).

[0128] Unless otherwise specifically stated, the chemical composition of the workpieces 106, 108 disclosed herein does not include the chemical composition of any coating 118 (e.g., an aluminum based coating on the base substrate steel sheet of the workpiece 106, 108). Accordingly, the chemical composition of the workpiece 106, 108 is a chemical composition of the base steel substrate of the workpiece 106, 108. a. High Strength Steel Workpiece(s) 106, 108

[0129] According to various embodiments, one or both of the workpieces 106, 108 comprise a high strength steel, for example, a press hardenable steel (PHS) such as ultra high strength steel (UHSS).

[0130] According to various embodiments, the high strength steel comprises hot or cold rolled manganese-boron (MnB) steel.

[0131] Unless otherwise specifically stated herein, all references to tensile strength refer to tensile strength after heat treatment (i.e., quenching).

[0132] According to various embodiments, the high strength steel workpiece(s) 106, 108 may have a tensile strength (after heat treatment) of at least 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, and / or 2000 MPa. According to various embodiments, high strength steel may also have a tensile strength (after heat treatment) that is less than or equal to 2500, 2400, 2300, 2200, 2100, 2000, 1900, 1800, 1700, 1600, 1500, 1400, and / or 1300 MPa (e.g., a steel with a tensile strength of between 1200 and 2500 MPa). According to various embodiments, high strength steel may have a tensile strength (after heat treatment) between any two such lower and upper limits (e.g., 1200-2500 MPa, 1200-2000 MPa, 1200-1650 MPa). Various high strength steels that are well suited for use in one or more embodiments (e.g., embodiments welding high strength steel to low strength steel to provide differential properties (e.g., crumple zones)) has a tensile strength (after heat treatment) of between 1300 and 1700 MPa or between 1800 and 2200 MPa. Examples of high strength steels include ArcelorMittal Usibor® (e.g., Usibor® 1500, Usibor® 2000), high strength ThyssenKrupp (TK) steels (e.g., TK MBW®1200, TK MBW-W 1500, TK MBW 1500, TK MBW-K 1500, and TK MBW-K 1900), and equivalent or comparable steels made by other manufacturers.

[0133] According to various nonlimiting embodiments, a tensile strength of a high strength steel before heat treatment may be about 400-750 MPa.

[0134] According to various embodiments, the high strength steel may have the following chemical composition:• Carbon: According to one or more non-limiting embodiments, the carbon concentration may be:• greater than or equal to 0.1%, 0.14%, 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and / or 0.45%; less than or equal to 0.5%, 0.45%, 0.40%, 0.38%, 0.3%, 0.25%, 0.2%, and / or 0.15%; and / or between any two such lower and upper values (e.g., 0.10% < C < 0.5%; 0.15% < C < 0.25%; 0.15% < C < 0.38%; 0.15% < C < 0.4%).According to various embodiments, carbon in the above-discussed concentrations may increase the strength of the steel. However increasing the carbon concentration can decrease weldability and toughness. The above concentrations were found to be effective in various embodiments.Manganese: According to one or more non-limiting embodiments, the manganese concentration (if present) may be:• greater than or equal to 0%, 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and / or 3.0%;• less than or equal to 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, and / or 0.2%; and / or• between any two such lower and upper values (e.g., 0% < Mn < 3.0%; 0.001% < Mn < 5.0%; Mn 0.1% < Mn < 5.0%; 0.5% < Mn < 2.0%; 0.8% < Mn < 1.8%; 0.4% < Mn < 3%).• According to various embodiments, manganese in the above-discussed concentrations may increase the steel’s strength and assists with deoxidation. Manganese has a milder effect than carbon, so the use of manganese may retain the steel’s weldability.Silicon: According to one or more non-limiting embodiments, the silicon concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, and / or 0.5%;• less than or equal to 2.0%, 1.5%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05%, and / or 0.01%; and / or• between any two such lower and upper values (e.g., 0.0% < Si < 2%; 0.001% < Si < 1%; 0.01% < Si < 1.0%; 0.1% < Si < 1.0%).• According to various embodiments, silicon in the above-discussed concentrations may increase the steel’s strength. Silicon has a milder effect than manganese and consequently than carbon (castability improvement).Chromium: According to one or more non-limiting embodiments, the chromium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%, and / or 2.5%;• less than or equal to 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Cr < 3%; 0.0% < Cr < 2%; 0.001% < Cr < 3%, 0.01% < Cr < 3%; 0.01% < Cr < 2%; 0.01% < Cr < 1%).• According to various embodiments, chromium in the above-discussed concentrations may result in improved corrosion resistance, increased hardenability, higher toughness, higher impact strength, and / or greater fatigue resistance.Molybdenum: According to one or more non-limiting embodiments, the molybdenum concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, and / or 0.9%;• less than or equal to 1.0%, 0.9%, 0.8%, 0.7%, 0.65%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Mo < 1.0%; 0.0% < Mo < 0.65%; 0.4% < Mo < 1.1%; 0.0% < Mo < 0.65%; 0.0% < Mo < 0.1%).• According to various embodiments, molybdenum in the abovediscussed concentrations may result in increased hardenability and high temperature strength.Niobium: According to one or more non-limiting embodiments, the niobium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.015%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, and / or 0.15%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.05%, and / or 0.01%; and / or• between any two such lower and upper values (e.g., 0.0% < Nb < 0.2%; 0.0% < Nb < 0.1%; 0.001% < Nb < 0.1%; 0.01% < Nb < 0.2%).• According to various embodiments, niobium in the above-discussed concentrations may increase the steel’s yield strength and tensile strength.Titanium: According to one or more non-limiting embodiments, the titanium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, and / or 0.15%;• less than or equal to 0.2%, 0.18%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Ti < 0.2%).• According to various embodiments, titanium in the above-discussed concentrations may increase the steel’s yield strength, hardness and toughness. Titanium may reduce the oxygen and / or nitrogen in the molten steel.Niobium + Titanium: According to one or more non-limiting embodiments, the cumulative concentration of niobium and titanium (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, and / or 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, and / or 0.1%;• less than or equal to 0.2%, 0.18%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Ti+Nb < 0.2%; 0.0% < Ti+Nb < 0.1%; 0.05% < Ti+Nb < 0.18%).• According to various embodiments, Ti and Nb each help to strengthen the steel, so their cumulative concentration helps to strengthen the steel.Aluminum: According to one or more non-limiting embodiments, the aluminum concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, and / or 0.3%;• less than or equal to 0.4%, 0.3%, 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Al < 0.4%; 0.0% < Al < 0.1%; 0% < Al < 0.07%; 0% < Al < 0.05%; 0.01% < Al < 0.4%; 0.01% < Al < 0.1%; 0.001% < Al < 0.1%; 0.01% < Al < 0.07%).• Aluminum in the above-stated small concentrations may beneficially reducing oxygen and / or nitrogen in the molten steel while not being so concentrated that the aluminum makes the steel unduly brittle.Nickel: According to one or more non-limiting embodiments, the nickel concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < Ni < 0.2%; 0.0% < Ni < 0.15%; 0.0% < Ni < 0.1%).• According to various embodiments, nickel in the above-discussed concentrations may result in higher strength, hardness, hardenability, ductility, and toughness.Sulfur: According to one or more non-limiting embodiments, the sulfur concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, and / or 0.05%;• less than or equal to 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < S < 0.05%; 0.0% < S < 0.01%; 0.0% < S < 0.005%; 0.0% < S < 0.001%).• Sulfur is typically present in the steel as an iron impurity (reducing toughness and ductility) whose concentration is preferably limited so as to be less than or equal to 0.05% and / or 0.01%.Phosphorus: According to one or more non-limiting embodiments, the phosphorus concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < P < 0.1%; 0.001% < P < 0.025%; 0.0% < P < 0.06%).• Phosphorus is typically present in the steel as an iron impurity (reducing toughness and ductility, can increase strength) whose concentration is preferably limited so as to be less than or equal to 0.1% and / or 0.06%.Boron: According to one or more non-limiting embodiments, the boron concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, and / or 0.009%;less than or equal to 0.01%, 0.009%, 0.008%, 0.007%, 0.006%,0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < B < 0.010%; 0.0% < B < 0.008%; 0.0% < B < 0.005%; 0.001% < B < 0.010%; 0.001% < B < 0.008%; 0.001% < B < 0.005%).• Boron may improve the steel’s hardenability and strength. Boron’s concentration is preferably limited to avoid ductility reduction and to retain weldability.Nitrogen: According to one or more non-limiting embodiments, the nitrogen concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, and / or 0.015%;• less than or equal to 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < N < 0.02%; 0.0% < N < 0.01%; 0.0% < N < 0.009%; 0.003% < N < 0.010%; ~ 0.005%).• According to various embodiments, N is not beneficial to the types of automative steels to which various embodiments are directed. Rather, in various embodiments relating to certain steels (e.g., automotive steels), N causes aging and porosity, which makes the steel detrimentally brittle. As a result, according to various embodiments, N is an impurity, rather than an intentional alloying element. According to various embodiments, N concentration should not exceed 0.01% (e.g., various industry and customer specifications).According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0135] As used herein, a trace element means an element that was not intentionally included in the composition for a purpose. A trace element may have a concentration of less than 0.1%, 0.01%, and / or 0.005%.

[0136] As used herein, impurities include elements that are detrimental and / or unavoidable using reasonable / practical manufacturing techniques (e.g., S, P, and N).

[0137] According to various embodiments, the high strength steel may have the following chemical composition:• 0.10% < C < 0.5%;• 0.1% < Mn < 3% (e.g., 0.4% < Mn < 3%);• 0.01% < Si < 1%;• 0.001% < Cr < 2%;• 0.0% < Mo < 0.65%;• 0.0% < Nb < 1% (e.g., 0.0% < Nb < 0.2%);• 0.0% < Ti < 0.2%;• 0.001% < Al < 0.1%;• 0.0% < S < 0.05% (e.g., 0.0% < S < 0.01%);• 0.0% < P < 0.1% (e.g., 0.0% < P < 0.06%);• 0.0% < V < 0.2%;• 0.0% < B < 0.010%; and / or• 0.0% < N < 0.02% (e.g., 0.0% < N < 0.01%; 0.0% < N < 0.009%; 0.0% < N < 0.005%; 0.0% < N < 0.001%).According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0138] According to various embodiments, the high strength steel comprises Fe and at least one of C, Mn, Si, Cr, Ti, Al, V, and B. According to various embodiments, the high strength steel comprises Fe and at least one of C, Mn, Si, Cr, Ti, Al, S, P, V, and B. According to various embodiments, the high strength steel comprises Fe, C, Mn, and Si. According to various embodiments, the high strength steel additionally comprises Cr, Mo, Nb, Ti, Al, and / or B. According to various embodiments, the high strength steel additionally comprises impurities such as S, P, and / or N. According to various embodiments, the high strength steel may comprise Fe, C, Mn, Si, S, P, Al, and N. According to various embodiments, the high strength steel additionally comprises V. According to various embodiments, the concentration of any of the elements described in this paragraph may fall within the upper limits, lower limits, and / or ranges disclosed in this subsection for such elements.

[0139] According to various embodiments, the high strength steel may have the following chemical composition:0.10% < C < 0.5%;0.5% < Mn <3%;0.1% < Si < 1%;0.01% < Cr < 1%;0.0% < Ti < 0.2%;0.0% < Al < 0.1%;0.0% < S < 0.05%;0.0% < P < 0.1%; and0.0% < B < 0.010%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0140] According to various embodiments, the high strength steel may have the following chemical composition:0.15% < C < 0.25%;0.8% < Mn < 1.8%;0.1% < Si < 0.35%;0.01% < Cr < 0.5%;0.0% < Ti < 0.1%;0.0% < Al < 0.1%;0.0% < S < 0.05%;0.0% < P < 0.1%; and0.0% < B < 0.005%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0141] According to various embodiments, the high strength steel may have the following chemical composition:0.24% < C < 0.38%;0.40% < Mn <3%;0.10% < Si < 0.70%;0.015% < Al < 0.070%;0.0% < Cr < 2%;0.25% < Ni < 2%;0.015% < Ti < 0.10%;0.0% < Nb < 0.060%;0.0005% < B < 0.0040%;0.003% < N < 0.010%;0.0001% < S < 0.005%; and0.0001% < P < 0.025%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0142] According to various embodiments, the high strength steel (e.g., Usibor 1500) may have the following chemical composition:0.0% < C < 0.25% (e.g., ~ 0.23%);0.0% < Si < 0.4% (e.g., ~ 0.25%);0.0% < Mn < 1.4% (e.g., ~ 1.2%);0.0% < P < 0.03% (e.g., ~ 0.016%);0.0% < S < 0.01% (e.g., ~ 0.001%);0.01% < Al < 0.1%;0.0% < Ti < 0.05%;0.0% < Nb < 0.01%;0.0% < Cu < 0.2%;0.0% < B < 0.005% (e.g., ~ 0.003%);0.0% < Cr < 0.35%;0.0% < N < 0.02% (e.g., 0.0% < N < 0.01%; 0.0% < N < 0.009%); and0.0% < Mo < 2% (e.g., Mo < 1.0%; Mo < 0.1%; Mo < 0.01%; Mo < 0.001%).According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0143] According to various embodiments, an Usibor 1500 workpiece 106, 108 comprises 0.2249% C (e.g., 0.2000-0.2500% C), 1.1719% Mn (e.g., 1.1000-1.5000% Mn), 0.0103% P (e.g., 0.0250% max P), 0.0007% S (e.g., 0.0050% max S), 0.2527% Si (e.g., 0.5000% max Si), 0.0275% Al (e.g., 0.0150-0.0800% Al), 0.0061% N (e.g., 0.0100% max N), 0.0026% B (e.g., 0.0020-0.0050% B), 0.0367 % Ti (e.g., 0.0200- 0.0500% Ti), 0.0003% Nb, 0.0025% V, 0.0150% Ni (e.g., 0.1000% max Ni), 0.1803% Cr (e.g., 0.2500% max Cr), 0.0161% Cu (e.g., 0.2000% max Cu), 0.0023% Mo (e.g., 0.3500% max Mo), 0.0079% Sn, 0.0000% Zr, and 0.0017% As.

[0144] According to various embodiments, the high strength steel (e.g., TK MBW 1200) may have the following chemical composition:0.0% < C < 0.14%;0.0% < Si < 0.4%;0.0% < Mn < 1.8%;0.0% < P < 0.025%;0.0% < S < 0.01%;0.0% < Al < 0.15%;0.0% < Ti < 0.05%;0.0% < Nb < 0.05%;0.0% < B < 0.005%; and0.0% < (Cr+Mo) < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0145] According to various embodiments, the high strength steel (e.g., TK MBW-W 1500, TK MBW 1500) may have the following chemical composition:0.0% < C < 0.25%;0.0% < Si < 0.4%;0.0% < Mn < 1.4%;0.0% < P < 0.025%;0.0% < S < 0.01%;0.015% < Al;0.0% < Ti < 0.05%;0.0% < Nb < 1% (e.g., Nb < 0.1%; Nb < 0.01%; Nb < 0.001%);0.0% < Cu < 0.2% (e.g., Cu < 0.1%; Cu < 0.01%; Cu < 0.001%);0.0% < B < 0.005%; and0.0% < (Cr+Mo) < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0146] For example, a TK MBW 1500 workpiece 106, 108 may comprise 0.222% C, 0.220% Si, 1.110% Mn, 0.010% P, 0.0015% S, 0.044% Al, 0.0023% B, 0.184% Cr, 0.009% Cr, 0.002% Mo, 0.0044% N, 0.001% Nb, 0.015% Ni, and 0.033% Ti.

[0147] According to various embodiments, the high strength steel (e.g., TK MBW-K 1900) may have the following chemical composition:0.0% < C < 0.38%;0.0% < Si < 0.4%;0.0% < Mn < 1.4%;0.0% < P < 0.025%;0.0% < S < 0.01%;0.015% < Al;0.0% < Ti < 0.05%;0.0% < Nb < 1% (e.g., Nb < 0.1%; Nb < 0.01%; Nb < 0.001%);0.0% < Cu < 0.2% (e.g., Cu < 0.1%; Cu < 0.01%; Cu < 0.001%);0.0% < B < 0.005%; and0.0% < (Cr+Mo) < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0148] According to various embodiments, the high strength steel (e.g., Usibor 2000) may have the following chemical composition:0.0% < C < 0.36%;0.0% < Si < 0.8%;0.0% < Mn < 0.8%;0.0% < P < 0.03%;0.0% < S < 0.01%;0.01% < Al < 0.06%;0.0% < Ti < 0.07%;0.02% < Nb < 0.07%;0.0% < Cu < 0.2%;0.0% < B < 0.005%;0.0% < Cr < 0. 5%; and0.0% < Mo < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0149] According to one or more embodiments the high strength workpiece(s) 106, 108 (e.g., SABC1470) may comprise:• 0.22% < C < 0.25%;• 0.2% < Si < 0.3%;• 1.1% < Mn < 1.3%;• 0.0% < P < 0.018%;• 0.0% < S < 0.005%;• 0.01% < Al < 0.05%;• 0.0025% < B < 0.0035%;• 0.0% < N < 0.005%;• 0.15% < Cr < 0.25%;• 0.025% < Ti < 0.035%; and• 0.0% < Mo < 0.08%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0150] According to various non-limiting embodiments, the high strength steel workpiece 106, 108 comprises iron and at least 0.10% carbon and / or at least 0.15% carbon. The workpiece 106, 108 may additionally include any one or more of the following elements: Mn, Si, Cr. Ti, Al, S, P, and B. b. Low Strength Steel Workpiece(s) 106, 108

[0151] According to various embodiments, one or both of the workpieces 106, 108 comprise a low strength steel, for example, a micro-alloyed or low-alloyed, high strength steel (HSLA). According to various embodiments, the low strength steel is hot or cold rolled.

[0152] As used herein, the term “low strength” is defined relative to the “high strength” steels discussed above. On an absolute scale, both low and high strength steels may be considered high and / or ultra high strength steels. According to various embodiments, the low strength steel workpiece(s) 106, 108 may have a lower tensile strength (after heat treatment) than the above-discussed high strength steel workpiece(s) 106, 108. According to variousembodiments, the low strength steel workpiece(s) 106, 108 may be less press-hardenable than the above-discussed high strength steel workpiece(s) 106, 108.

[0153] According to various embodiments, the low strength steel workpiece(s) 106, 108 may have a tensile strength (after heat treatment) of less than 1200, 1100, 1000, 900, 800, 700, 600, 500, and / or 400 MPa. According to various embodiments, low strength steel may also have a tensile strength (after heat treatment) that is at least 400, 500, 600, 700, 800, 900, 1000, and / or 1100 MPa (e.g., a steel with a tensile strength of between 400 and 1100 MPa). According to various embodiments, low strength steel may have a tensile strength (after heat treatment) between any two such upper and lower limits, e.g., 400-1200 MPa, 400-600 MPa. Examples of low strength steel that is well suited to be welded to high strength steel to provide differential strengths (e.g., crumple zones) have a tensile strength (after heat treatment) of between 400 and 600 MPa. Examples of low strength steels include ArcelorMittal’s Ductib or (e.g., Ductibor 450, Ductibor 500, Ductibor 1000), Thyssenkrupp’s low strength steels (e.g., TK MBW 500, TK MBW 600), and equivalent or comparable steels made by other manufacturers.

[0154] According to various embodiments, the low strength steel workpiece 106, 108 is substantially not press-hardenable.

[0155] According to various embodiments, the low strength steel workpiece 106, 108 may have the following chemical composition:• Carbon: According to one or more non-limiting embodiments, the carbon concentration may be:• greater than or equal to 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.15%, 0.14%, 0.13%, 0.12%, 0.11%, 0.1%, 0.09%, 0.08%, 0.07%, and / or 0.06%; and / or• between any two such lower and upper values (e.g., 0.02% < C < 0.15%; 0.04% < C < 0.10%).• According to various embodiments, carbon in the above-discussed concentrations may increase the strength of the steel. However increasing the carbon concentration can decrease weldability and toughness. The above concentrations were found to be effective in various embodiments.Manganese: According to one or more non-limiting embodiments, the manganese concentration (if present) may be:• greater than or equal to 0%, 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, and / or 3.0%;• less than or equal to 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, and / or 0.2%; and / or• between any two such lower and upper values (e.g., 0% < Mn < 3%; 0.001% < Mn < 3%; Mn 0.1% < Mn < 3%; 0.5% < Mn < 2.0%; 0.8% < Mn < 2.0%; 0.8% < Mn < 1.8%; 0.4% < Mn < 3%).• According to various embodiments, manganese in the above-discussed concentrations may increase the steel’s strength and assists with deoxidation. Manganese has a milder effect than carbon, so the use of manganese may retain the steel’s weldability.Silicon: According to one or more non-limiting embodiments, the silicon concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, and / or 0.5%;• less than or equal to 1.5%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05%, and / or 0.01%; and / or• between any two such lower and upper values (e.g., 0.0% < Si < 1.5%; 0.001% < Si < 1%; 0.01% < Si < 1.0%; 0.1% < Si < 1.0%; 0.0% < Si < 0.30%).• According to various embodiments, silicon in the above-discussed concentrations may increase the steel’s strength. Silicon has a milder effect than manganese and consequently than carbon (castability improvement).Sulfur: According to one or more non-limiting embodiments, the sulfur concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, and / or 0.05%;• less than or equal to 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < S < 0.05%; 0.0% < S < 0.01%; 0.0% < S < 0.005%; 0.0% < S < 0.001%).• Sulfur is typically present in the steel as an iron impurity (reducing toughness and ductility) whose concentration is preferably limited so as to be less than or equal to 0.05% and / or 0.01%.Phosphorus: According to one or more non-limiting embodiments, the phosphorus concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < P < 0.06%; 0.0% < P < 0.030%).• Phosphorus is typically present in the steel as an iron impurity (reducing toughness and ductility, can increase strength) whose concentration is preferably limited so as to be less than or equal to 0.1% and / or 0.06%.Aluminum: According to one or more non-limiting embodiments, the aluminum concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.14%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Al < 0.14%; 0.0% < Al < 0.1%; 0% < Al < 0.07%; 0.001% < Al < 0.14%; 0.001% < Al < 0.1%; 0.01% < Al < 0.07%).• Aluminum in the above-stated small concentrations may beneficially reducing oxygen and / or nitrogen in the molten steel while not being so concentrated that the aluminum makes the steel unduly brittle.Niobium: According to one or more non-limiting embodiments, the niobium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.015%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, and / or 0.15%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.05%, and / or 0.01%; and / or• between any two such lower and upper values (e.g., 0.0% < Nb < 0.2%; 0.0% < Nb < 0.15%; 0.0% < Nb < 0.1%; 0.001% < Nb < 0.2%; 0.01% < Nb < 0.2%; 0.015% < Nb < 0.100%).• According to various embodiments, Ti and Nb each help to strengthen the steel, so their cumulative concentration helps to strengthen the steel.Titanium: According to one or more non-limiting embodiments, the titanium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, and / or 0.15%;• less than or equal to 0.2%, 0.18%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Ti < 0.2%; 0.0% < Ti < 0.1%; 0.0% < Ti < 0.080%).• According to various embodiments, titanium in the above-discussed concentrations may increase the steel’s yield strength, hardness and toughness. Titanium may reduce the oxygen and / or nitrogen in the molten steel.Niobium + Titanium: According to one or more non-limiting embodiments, the cumulative concentration of niobium and titanium (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, and / or 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, and / or 0.1%;• less than or equal to 0.2%, 0.18%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Ti+Nb < 0.2%; 0.0% < Ti+Nb < 0.1%; 0.05% < Ti+Nb < 0.18%).• According to various embodiments, Ti and Nb each help to strengthen the steel, so their cumulative concentration helps to strengthen the steel.Nitrogen: According to one or more non-limiting embodiments, the nitrogen concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, and / or 0.015%;• less than or equal to 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < N < 0.02%; 0.0% < N < 0.01%; 0.0% < N < 0.009%; 0.0% < N < 0.005%; 0.0% < N < 0.001%).• According to various embodiments, N is not beneficial to the types of automative steels to which various embodiments are directed. Rather, in various embodiments relating to certain steels (e.g., automotive steels), N causes aging and porosity, which makes the steel detrimentally brittle. As a result, according to various embodiments, N is an impurity, rather than an intentional alloying element. According to various embodiments, N concentration should not exceed 0.01% (e.g., various industry and customer specifications).Copper: According to one or more non-limiting embodiments, the copper concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < Cu < 0.2%; 0.0% < Cu < 0.100%).• According to various embodiments, Cu is not an intentional alloy, but is instead an iron impurity (reduces ductility, toughness and weldability).Nickel: According to one or more non-limiting embodiments, the nickel concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < Ni < 0.2%; 0.0% < Ni < 0.15%; 0.0% < Ni < 0.1%).• According to various embodiments, nickel in the above-discussed concentrations may result in higher strength, hardness, hardenability, ductility, and toughness.Chromium: According to one or more non-limiting embodiments, the chromium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, and / or 0.15%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Cr < 0.2%; 0.0% < Cr < 0.15%; 0.0% < Cr < 0.10%).• According to various embodiments, chromium in the above-discussed concentrations may result in improved corrosion resistance, increased hardenability, higher toughness, higher impact strength, and / or greater fatigue resistance.Molybdenum: According to one or more non-limiting embodiments, the molybdenum concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, and / or 0.2%;• less than or equal to 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Mo < 0.3%; 0.0% < Mo < 0.15%; 0.0< Mo < 0.1%).• According to various embodiments, molybdenum in the abovediscussed concentrations may result in increased hardenability and high temperature strength.• Calcium: According to one or more non-limiting embodiments, the calcium concentration (if present) may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, and / or 0.006%;• less than or equal to 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < Ca < 0.01%; 0.0% < Ca < 0.006%).• According to various embodiments, Ca is not an intentional alloying element, and is not materially pertinent to the steel’s properties.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0156] For example, according to various embodiments, the low strength steel may have the following chemical composition:0.040% < C < 0.100%;0.80% < Mn < 2.00%;0.0% < Si < 0.30%;0.0% < S < 0.005%;0.0% < P < 0.030%;0.010% < Al < 0.070%;0.015% < Nb < 0.100%;0.0% < Ti < 0.080%;0.0% < N < 0.009%;0.0% < Cu < 0.100%;0.0% < Ni < 0.100%;0.0% < Cr < 0.100%;0.0% < Mo < 0.100%; and0.0% < Ca < 0.006%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0157] According to various embodiments, the low strength steel comprises Fe and at least one of C, Mn, Si, Al, Nb, Ti, Ni, Cr, and Mo. According to various embodiments, the low strength steel comprises Fe, C, Mn, Al, and Nb. According to various embodiments, the low strength steel additionally comprises Si, Ti, Ni, Cr, and / or Mo. According to various embodiments, the low strength steel additionally comprises impurities such as S, P, N, Cu, and / or Ca. According to various embodiments, the concentration of any of the elements described in this paragraph may fall within the upper limits, lower limits, and / or ranges disclosed in this subsection for such elements.

[0158] According to various embodiments, the low strength steel (e.g., Ductibor 450) may have the following chemical composition:C < 0.1%;Si < 0.06%;Mn < 0.6%;P < 0.03%;S < 0.025% (e.g., S < 0.01%);0.015 < Al < 0.2%;Ti < 0.15%;Nb < 0.08% ;Cu < 0.2%;B < 0.001%;Cr < 0.2%; andMo < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0159] For example, a Ductibor 450 workpiece 106, 108 may comprise 0.0567% C, 0.3337% Mn, 0.0107% P, 0.0121% S, 0.0074% Si, 0.0400% Al, 0.0561% Nb, 0.0002% V, 0.0008% Ti, 0.0029% N, 0.0210% Cu, 0.0150% Ni, 0.0290% Cr, 0.0014% Mo, 0.0040% Sn, 0.0022% As, 0.0000% Zr, and 0.0000% Pb. In another example, a Ductibor workpiece 106, 108 may comprise 0.0656% C, 0.3327% Mn, 0.0123% P, 0.0104% S, 0.0092% Si, 0.0382% Al, 0.0550% Nb, 0.0004% V, 0.0009% Ti, 0.0032% N, 0.0200% Cu, 0.0143% Ni, 0.0286% Cr, 0.0023%Mo, 0.0042% Sn, 0.0021% As, 0.0000% Zr, and 0.0000% Pb. In another example, a Ductibor workpiece 106, 108 may comprise 0.0603% C, 0.3265% Mn, 0.0133% P, 0.0077% S, 0.0086% Si, 0.0388% Al, 0.0568% Nb, 0.0003% V, 0.0009% Ti, 0.0036% N, 0.0100% Cu, 0.0104% Ni, 0.0225% Cr, 0.0007% Mo, 0.0010% Sn, 0.0016% As, 0.0000% Zr, and 0.0000% Pb.

[0160] According to various embodiments, the low strength steel (e.g., Ductibor 500) may have the following chemical composition:C < 0.1% (e.g., - 0.060%);Si < 0.5% (e.g., - 0.032%);Mn < 1.7% (e.g., - 1.545%);P < 0.03% (e.g., - 0.016%);S < 0.025% (e.g., - 0.002%);0.015 < Al < 0.2% (e.g., - 0.035%);Ti < 0.09% (e.g., - 0.069%);Nb < 0.1% (e.g., - 0.047%);Cu < 0.2%;B < 0.001% (e.g., - 0.001%);Cr < 0.2%; and0.0% < Mo < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0161] According to various embodiments, the low strength steel (e.g., TK MBW 500) may have the following chemical composition:• 0.0% < C < 0.10% (e.g., -0.05% C);• 0.0% < Si < 0.35% (e.g., -0.20% Si);• 0.0% < Mn < 1.00% (e.g., -0.77% Mn);• 0.0% < P < 0.03% (e.g., -0.017% P);• 0.0% < S < 0.025% (e.g., -0.002% S);• 0.015% < Al;• 0.0% < Ti < 0.15%;• 0.0% < Nb < 0.1%;• 0.0% < B < 0.005%; and• 0.0% < (Cr+Mo) < 5% (e.g., (Cr+Mo) < 1.0%, < 0.5%, < 0.1%, < 0.01%, and / or < 0.001%; -0.03% Cr and -0.003% Mo).According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0162] For example, a TK MBW 500 workpiece 106, 108 may comprise 0.062% C, 0.199% Si, 0.800% Mn, 0.018% P, 0.0020% S, 0.036% Al, 0.0003% B, 0.018% Nb, and 0.002% Ti.

[0163] According to one or more embodiments the low strength workpiece 106, 108 (e.g., SABC550 PSA-HS500T) may comprise:• 0.04% < C < 0.07%;• 0.0% < Si < 0.06%;• 1.55% < Mn < 1.75%;• 0.0% < P < 0.02%;• 0.0% < S < 0.003%;• 0.01% < Al < 0.05%;• 0.0% < B < 0.001%;• 0.0% < N < 0.006%;• 0.0% < Cr < 0.1%; and• 0.065% < Ti < 0.075%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0164] According to one or more embodiments the low strength workpiece 106, 108 (e.g., SABC980) may comprise:• 0.04% < C < 0.07%;• 0.45% < Si < 0.55%;• 1.75% < Mn < 1.9%;• 0.0% < P < 0.015%;• 0.0% < S < 0.003%;• 0.01% < Al < 0.05%;• 0.0015% < B < 0.0025%;• 0.0% < N < 0.005%;• 0.15% < Cr < 0.25%;• 0.015% < Ti < 0.025%; and• 0.0% < Mo < 0.08%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0165] According to various embodiments, the low strength steel (e.g., TK MBW 600) may have the following chemical composition:0.0% < C < 0.10%;0.0% < Si < 0.5%;0.0% < Mn < 2.00%;0.0% < P < 0.03%;0.0% < S < 0.025%;0.015% < Al;0.0% < Ti < 0.15%;0.0% < Nb < 0.1%;0.0% < B < 0.005%; and0.0% < (Cr+Mo) < 5% (e.g., (Cr+Mo) < 1.0%, < 0.5%, < 0.1%, < 0.01%, and / or < 0.001%).According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0166] According to various embodiments, the low strength steel (e.g., Ductibor 1000) may have the following chemical composition:C < 0.1%;Si < 0.6%;Mn < 1.8%;P < 0.03%;S < 0.01%;0.01 < Al < 0.1%;Ti < 0.05%;Nb < 0.1%;Cu < 0.2%;B < 0.005%;Cr < 0.2%; and0.0% < Mo < 0.5%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0167] According to various embodiments, any of the above-discussed high and / or low strength steel may additionally and / or alternatively comprise:0.05% < Mo < 0.65%;0.001% < W < 0.30%%; and / or0.0005 % < Ca < 0.005%.According to various non-limiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0168] According to various non-limiting embodiments, the low strength steel workpiece 106, 108 comprises iron and carbon, wherein the carbon concentration is less than 0.15% and / or less than 0.1%. The workpiece 106, 108 may additionally include any one or more of the following elements: Mn, Si, Cr. Ti, Al, S, P, and B. c. Workpiece 106, 108 Composition Combinations

[0169] According to various alternative embodiments, the workpieces 106, 108 comprise: (1) a high strength workpiece 106, 108 and a low strength workpiece 106, 108, (2) two high strength workpieces 106, 108, or (3) two low strength workpieces 106, 108.

[0170] In various non-limiting embodiments: i) one of the workpieces 106, 108 is formed from Usibor® (high strength) steel and the other of the workpieces 106, 108 is formed from Ductibor® (low strength) steel; ii)one of the workpieces 106, 108 is formed from Usibor® (high strength) 1500 steel and the other of the workpieces 106, 108 is formed from Ductibor® (low strength) 500 steel; iii) one of the workpieces 106, 108 is formed from Usibor® (high strength) 1500 steel and the other of the workpieces 106, 108 is formed from TK-MBW® (low strength) 500 steel; iv) one of the workpieces 106, 108 is formed from Usibor® (high strength) 1500 steel and the other of the workpieces 106, 108 is formed from TK-MBW ® (low strength) 600 steel; v) one of the workpieces 106, 108 is formed from TK-MBW® (high strength) 1500 steel and the other of the workpieces 106, 108 is formed from Ductibor® (low strength) 500 steel;vi) one of the workpieces 106, 108 is formed from TK-MBW® (high strength) 1500 steel and the other of the workpieces 106, 108 is formed from TK-MBW ® (low strength) 500 steel; vii)one of the workpieces 106, 108 is formed from TK-MBW® (high strength) 1500 steel and the other of the workpieces 106, 108 is formed from TK-MBW ® (low strength) 600 steel; viii) one of the workpieces 106, 108 is formed from Usibor® (high strength) 2000 steel and the other of the workpieces 106, 108 is formed from Ductibor® (low strength) 1000 steel; ix) each of the workpieces 106, 108 is formed from Ductibor® (low strength) steel; x) each of the workpieces 106, 108 is formed from Usibor® (high strength) steel; xi) each of the workpieces 106, 108 is formed from TK low strength steel, or xii)each of the workpieces is formed from TK high strength steel.

[0171] In one or more embodiments, the workpiece 106 and / or 108 includes Usibor® (a high resistance boron micro alloyed aluminum-silicon steel). In one or more embodiments, the workpieces 106 and / or 108 include Ductibor® (a high resistance boron micro alloyed aluminum-silicon steel).3. Patch Workpiece 106, 108

[0172] At least one of the steel workpieces 106, 108 may include a base / main / parent blank and a patch blank attached to the base blank. The base blank and the patch blank may have the same thickness. The base blank and the patch blank may be made of the same material. The base blank and the patch blank may be made of the same material grade.

[0173] The base blank and the patch blank may have different thicknesses. The thickness of the base blank and / or the patch blank may be (a) at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and / or 10.0 mm, (b) less than 15.0, 12.5, 10.0, 9.0, 8.0, 7.0, 6.0, 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, and / or 0.2 mm, and / or (c) between any two such values (e.g., between 0.1 and 15.0 mm, between 0.1 mm and 10 mm, between 0.5 and 2.5 mm). According to one or more embodiments, the base blank and the patch blank are each 2.0 mm thick. According to one or more other embodiments, the base blank is 2.3 mm and the patch blank is 1.8 mm. According to one or more embodiments, a combined thickness of the base blank and the patch blank may be (a) at least 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 12.5, 15.0 and / or 17.5 mm, (b) less than 20.0, 17.5, 15.0, 12.5, 10.0, 9.0,8.0, 7.0, 6.0, 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, and / or 0.3 mm, and / or (c) between any two such values (e.g., between 0.2 and 20.0 mm, between 1.0 mm and 10 mm, between 0.5 and 2.5 mm). The base blank and the patch blank may be made of different materials. The base blank and the patch blank may be made of different material grades. The patch blank may be spot welded to the base blank (e.g., one of the steel workpieces 106, 108) after the base blank is laser welded to another blank (e.g., the other of the steel workpieces 106, 108). At least one of the steel workpieces 106, 108 may have patch blanks on them. None of the steel workpieces 106, 108 may have patch blanks on them.4. Forming The Workpieces 106, 108

[0174] The steel workpieces 106, 108 may be manufactured by roll forming a steel sheet metal. A roll forming procedure generally is a type of rolling involving the continuous bending of a long strip of sheet metal (e.g., coiled steel) into a desired cross-sectional shaped configuration. The roll forming procedure may be performed in which the flattened steel sheet metal is progressively shaped. A roll forming system may include a plurality of pairs of roller die stands. The roll forming system is individually or gang driven to force the ribbon of steel sheet metal through the rollers that gradually shape the steel sheet metal to the desired cross- sectional shaped configuration. Pre-processing procedures may be performed before the roll forming procedure. The pre-processing procedures may include uncoiling from a roll / coil of steel sheet metal and flattening the steel sheet metal. The coil of the steel sheet metal may be loaded onto an uncoiler (e.g., a single or a double uncoiler) and then fed through a flattener to straighten / flatten the steel sheet metal. The pre-processing procedures may be optional.

[0175] The workpieces 106, 108 may then be cut out of such sheet material, e.g., via die-cutting, laser cutting, etc., to have a desired shape. This process may also be used to form a desired edge for the workpiece 106, 108 edge to be welded (e.g.: a square edge that is perpendicular to the opposing side surfaces of the workpiece 106, 108 for a butt-joint; a slanted edge for a lap joint).

[0176] Edges of the two steel workpieces 106, 108 that are to be welded together may be die cut, laser cut, ground, machined, polished, or shear cut. According to various embodiments, different procedures may be used to form different edges along the perimeter of each workpiece 106, 108. For example, some edges (that are not part of the weld edges) of the two steel workpieces 106, 108 may be die cut, while other edges (e.g., edges to be welded) may be laser cut. A shear cut procedure may be used to trim / cut the edges of the two steel workpieces 106, 108 that are welded together. Cutting is a procedure during which the steelworkpiece(s) 106, 108 is shaped by removing excess material. This process includes such technologies as CNC milling, laser cutting, etc. Laser cutting works like regular machining, except that instead of mechanical tools, laser cutting uses a laser to remove portions of the steel workpiece(s) 106, 108. The laser cutting can produce parts quicker and provide a better edge finish as the laser beam polishes and melts the steel workpiece(s) 106, 108.

[0177] According to various embodiments, laser cutting is used to form the workpieces 106, 108 when relatively fewer workpieces 106, 108 of a particular shape are to be used, given the ability of laser cutters to quickly and inexpensively switch between different shapes of work pieces 106, 108. According to various embodiments, die-cutting is used for larger quantities of a particular shape of workpiece 106, 108, given the relatively larger investment required to create a die for forming a particular shape for a workpiece 106, 108.

[0178] Weld edges of the two steel workpieces 106, 108 may be machined, for example, by undergoing a machining procedure (e.g., grinding procedure or milling procedure). Machining may include procedures in which a piece of steel workpiece(s) is cut into a desired shape and size by computer-controlled equipment. Such methods / procedures are often referred to as subtractive manufacturing. Milling may include procedures in which a cutting tool rotates, bringing cutting edges to bear against the steel workpiece(s) 106, 108. Milling machines are generally used in milling. Weld edges of the two steel workpieces 106, 108 may be trimmed.5. Workpiece Coatings 118

[0179] At least one of the steel workpieces 106, 108 (or both workpieces 106, 108) may include coating(s) 118 on their main surfaces (upper and lower surfaces as viewed in FIGS. 1- 2). In various embodiments, one of the workpieces 106, 108 has coating(s) 118 thereon and the other of the workpieces 106, 108 is uncoated (i.e., has no coating thereon). In another embodiment, both the workpieces 106, 108 have coatings 118 on them.

[0180] As noted above, at least one of the steel workpieces 106, 108 may include uncoated boron steel in which chrome may be used as a hardening material. The uncoated boron steel may be configured to not have scaling on the surface and not to carburize or oxidize during hot stamping. The uncoated steel / material may include an anti-scale coating 118 that is configured to prevent scaling on the uncoated steel. The anti-scale coating may interchangeably referred to as anti-scaling coating. The anti-scale coating may include an organic coating, a ceramic coating, a metallic coating, etc. The anti-scale coating only serves as a scale protection and can be removed during a shot blast procedure / process. One example of the anti-scaling coating may include Nano-X. In various embodiments, when both the steel workpieces 106,108 are uncoated and welded to each other, the weld joint 114 therebetween may include some aluminum therein. In other embodiments, the weld joint 114 therebetween may include no aluminum.

[0181] The coating(s) 118 may be applied to only a first side of one or both of the steel workpieces 106, 108. The coating(s) 118 may be applied to only an opposing, second side of one or both of the steel workpieces 106, 108. The coating(s) 118 may be applied to both the first side of one or both of the steel workpieces 106, 108 and the opposing, second side of one or both of the steel workpieces 106, 108.

[0182] The coating(s) 118 may be partially applied to (e.g., only a portion or some portions of) at least one of the steel workpieces 106, 108. That is, only the portion or some portions of at least one of the steel workpieces 106, 108 is / are coated (e.g., aluminum based coating such as an Al-Si coating) and the rest of the at least one of the steel workpieces 106, 108 may be uncoated. In such embodiments, the uncoated portions of the steel workpieces 106, 108 may undergo shot blasting procedure after the hot stamping procedure, while the coated portions do not undergo shot blasting procedure. The shot blasting is a mechanical process / procedure to remove the hot stamping / forming scales. In another embodiment, the uncoated portions of the steel workpieces 106, 108 may have the anti-scale coating (that is configured to prevent scaling on the uncoated steel) thereon. The uncoated portions (with the anti-scaling coating) of the steel workpieces 106, 108, therefore, do not undergo shot blasting procedure after the hot stamping procedure. The coating(s) may be fully applied to at least one of the steel workpieces 106, 108. The coating(s) may be applied to at least one of the steel workpieces 106, 108 before welding the steel workpieces 106, 108 to each other. The coating(s) may be applied to at least one of the steel workpieces 106, 108 before the hot stamping procedure in which the welded assembly including the two steel workpieces 106, 108 undergoes hot stamping / hot forming to a desired shape and configuration. The shaping procedure (i.e., shaping the steel workpiece / assembly while cooling it to provide the steel workpiece / assembly with the desired shape and strength) may be interchangeably referred to as press hardening procedure, hot stamping procedure or hot forming procedure. The coating(s) may be applied to at least one of the steel workpieces 106, 108 before the welding procedure (and before the hot stamping procedure). The coating(s) may be applied to the welded steel assembly (including the two steel workpieces 106, 108 and / or the weld joint 114) after the welding procedure but before the hot stamping procedure of the welded steel assembly. The coating(s) may be applied to the welded and hot stamped steel assembly (including the twosteel workpieces 106, 108 and / or the weld joint 114) after both the welding procedure and the hot stamping procedure.

[0183] At least one of the steel workpieces 106, 108 may have metallic, metal alloy, or metal based coating(s) 118. At least one of the steel workpieces 106, 108 may have aluminum- or aluminum alloy coating(s) 118 thereon. At least one of the steel workpieces 106, 108 may have silicone- or silicone alloy coating(s) 118 thereon. For example, at least one of the steel workpieces 106, 108 may be coated with aluminum-silicon coating(s) 118. At least one of the steel workpieces 106, 108 may have nickel, nickel additives, or nickel alloy coating(s) 118 thereon. For example, at least one of the steel workpieces 106, 108 may be coated with nickelchromium coating(s) 118. At least one of the steel workpieces 106, 108 may have zinc- or zinc- alloy coating(s) 118 thereon. At least one of the steel workpieces 106, 108 may have a coating 118 comprising zinc and aluminum. The coating comprising zinc and aluminum may be used to provide protection against corrosion. The addition of magnesium to the coating 118 comprising zinc and aluminum may increase the corrosion resistance of these coatings 118, which may reduce their thickness or increase the guarantee of protection against corrosion over time. At least one of the steel workpieces 106, 108 may have a coating 118 comprising zinc, magnesium and aluminum. The zinc, magnesium and aluminum coating 118 may be referred to as zinc-aluminum -magnesium or ZnAlMg coatings 118 and may include oiled zinc, magnesium, and aluminum coatings 118. At least one of the steel workpieces 106, 108 may have coatings 118 that include some additional elements chosen from Lead (Pb), Zirconium (Zr), or hafnium (Hf).

[0184] At least one of the steel workpieces 106, 108 may have intermetallic alloy coating 118. The coating(s) 118 may result from an interdiffusion between the steel workpieces 106, 108 and the coating(s) applied thereto. At least one of the steel workpieces 106, 108 may have non-metallic or non-metal based coating(s) 118 (e.g., Nano-X coating; resin coating; ceramic coating). One or more of these coatings may help to reduce scaling.

[0185] At least one and / or both of the steel workpieces 106, 108 may include a high emissivity coating 118 (e.g., black colored coating) (HEC) thereon that is configured to facilitate faster heating of the respective workpiece in the furnace prior to hot stamping. According to various embodiments, the HEC 118 may be selectively applied to certain areas of the main surface(s) and / or removed from selected areas of the main surface(s) of the workpiece(s) 106, 108 to selectively differentially heat the different regions of the workpiece(s) 106, 108 in the furnace. In particular, regions of the workpiece(s) 106, 108 whose surface(s)have the HEC 118 will heat faster and / or to a higher temperature than regions of the workpiece(s) 106, 108 whose surface(s) do not have the HEC 118. Subsequent quenching during the hot stamping process may result in relatively more martensite being formed in the regions of the workpiece(s) 106, 108 with the HEC than in regions without the HEC. Ways in which HEC 118 may be incorporated into various embodiments disclosed herein are further described in PCT Application No. PCT / IB2024 / 057005, filed July 19, 2024, titled “Hot Stamped Components With Tailored Properties And Method Of Forming the Same,” the entire contents of which are hereby incorporated by reference.

[0186] At least one of the steel workpieces 106, 108 may have coating(s) 118 thereon that include chrome additive(s). The chrome additive coating(s) 118 may be configured to create an oxide film on the respective workpiece 106, 108 so as to reduce or prevent corrosion. The chrome additive coating(s) 118 may be configured to prevent or reduce scaling on the respective workpiece 106, 108. The chrome additive coating(s) 118 may include chromium nickel alloys and / or chromium ferrite alloys.

[0187] According to various embodiments, the thickness of the coating for the blank / workpiece 106, 108 (either before and / or after hot stamping) may be (1) at least 5, 10, 15, 20, 25, 30, 35, 40, 45, and / or 50 microns thick, (2) less than 200, 175, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, 50, 40, 30, 20, and / or 10 microns thick, and / or (3) between any two such values (e.g., between 5 and 200 microns thick, between 10 and 120 microns thick, between 10 and 50 microns thick). The thickness of the coating 118 for the hot formed part (i.e., the blank / workpiece after it undergoes the hot forming procedure) may be in the same range, or may be in a different range. The chemical composition of the coating 118 for the blank / workpiece may include (1) aluminum, (2) aluminum and silicon (e.g., about 90% Al and 10% Si), or (3) aluminum, silicon, and iron (e.g., about 88% Al, about 9% Si, and about 3% Fe). The chemical composition of the coating for the hot formed part (i.e., the blank / workpiece after it undergoes the hot forming procedure) may include more or less iron than the coating 118 of the blank.

[0188] In one or more embodiments, each of the workpieces 106, 108 have an aluminum based coating 118 thereon. In one or more embodiments, each of the workpieces 106, 108 comprises the aluminum based coating 118 on both top and bottom surfaces 122 and 124. In one or more embodiments, the workpieces 106, 108 have an aluminum silicon coating 118 thereon.

[0189] At least one of the steel workpieces 106, 108 may include pre-diffused material. That is, the steel workpiece 106, 108 may be pre-diffused so as to have an Aluminum Silicon (Al — Si) coating 118. A pre-diffusion procedure may be performed before hot stamping procedure. The pre-diffusion procedure may include heating a steel substrate / workpiece 106, 108 (e.g., in furnace) to achieve pre-diffusion between the steel substrate / workpiece 106, 108 and a protective coating 118 (e.g., Al-Si coating), as well as the associated microstructure change. In the pre-diffusion procedure, the coating 118 may be diffused so as to combine with the steel workpiece 106, 108. The pre-diffused steel may include Iron Aluminum (Fe-Al) intermetallic alloy layer formed therein. According to various embodiments, the pre-diffusion process causes the coating thickness to grow.

[0190] According to various alternative embodiments, the aluminum based coating 118 is not pre-diffused into the steel substrate of the workpiece(s) 106, 108. Rather, the heating during the hot-stamping process after the workpieces 106, 108 are already welded together results in diffusion. To facilitate diffusion, the welded blank / assembly 110 may be held in the furnace at a temperature below the AC3 temperature of the workpieces 106, 108 for a dwell time (e.g., several minutes) to facilitate diffusion of the coating 118. This diffusion process causes a thickness of the aluminum based coating 118 to grow.

[0191] According to various embodiments, pre-diffusion of the coating 118 facilitates faster hot stamping because less time is required in the furnace for the diffusion process (if diffusion is intended). According to one non-limiting example, a pre-diffused workpiece 106, 108 may be heated in the furnace for about a minute, whereas 5-6 minutes of heating may have been needed to heat and diffuse the coating 118 of a non-pre-diffused coating 118.

[0192] According to various alternative embodiments, a zinc coating 118 may be used instead of an aluminum based coating.

[0193] In various embodiments, one or both the workpieces 106, 108 are uncoated (i.e., have no coatings 118 on them). The uncoated workpiece(s) 106, 108 may include uncoated boron steel in which chrome may be used as a hardening material.B . FILLER WIRE AND / OR POWDER

[0194] In an example weld joint 114 between a 1.2mm steel workpiece with an aluminum based coating and a 1.6 mm steel workpiece with an aluminum based coating, and without the addition of a metal filler wire or powder, the resulting welded joint (after heat treatment) has a minimum UTS of 800MPa, but less than 1200 MPa, and a minimum Vickers hardness of

[0195] The addition of small amounts of a metallurgical additive in the form of a metal powder or wire (i.e., consisting of substantial amounts of nickel and chromium) can modify the aluminum-iron reaction in the weld melt pool, and improve weld properties.

[0196] In one or more embodiments, small amounts of a metallurgical additive are added in the form of the filler wire 116. Additional studies have been performed with the metallurgical additive that yielded results that are more positive. It is also found that the metallurgical additive in the form of the filler wire 116 yields good quality welds in regards to strength, fatigue, and corrosion. The physical structure of the weld formed using the method according to one or more embodiments also meets the criteria of OEMs (Original Equipment Manufacturers). Since the metallurgical additive acts as a filler material, the laser welds handle variance in gap sizes well. In one or more embodiments, the filler wire 116 and powdered additive are applied simultaneously.

[0197] In one or more embodiments, the filler wire 116 is configured to reduce the effect of gap variances and fill in weld defects such as undercuts.

[0198] In one or more embodiments, the filler wire 116 comprises a composition that includes nickel. The filler wire may also include chromium. In one or more embodiments, the filler wire 116 is configured to bind with aluminum from the aluminum based coating 118 so as to minimize formation of brittle intermetallics due to mixing of the aluminum in the aluminum based coating 118 with iron or steel material in the weld joint 114.

[0199] In one or more embodiments, the filler wire 116 is configured to bind to aluminum in the aluminum based coating 118 so as to render the aluminum in the aluminum based coating 118 inert in the weld pool / joint 114. In one or more embodiments, the filler wire 116 is configured to bind to aluminum in the aluminum based coating 118 so as to prevent the formation of an aluminum - iron intermetallic phase in the weld bead / joint 114. In one or more embodiments, the filler wire 116 is configured to bind to aluminum in the aluminum based coating 118 so as to minimize mixing of the aluminum in the aluminum-based coating 118 with the iron / steel material in the weld joint 114.

[0200] In one or more embodiments, the filler wire 116 is also configured to bind with the aluminum based coating 118 to provide acceptable weld mechanical properties.

[0201] The use of filler wire 116, rather than filler powder, in accordance with one or more embodiments, is cleaner because loose powder (i.e., powdered additive) will not make its way onto the floor and / or tooling.

[0202] In one or more embodiments, the chemical composition of the filler wire 116 includes substantial amounts of nickel and chromium. In one or more embodiments, the nickel and chromium filler wire 116 is configured to bind with the aluminum in the aluminum-silicon coating of coated workpieces 106, 108 such as Usibor® steel. However, in other embodiments, nickel and / or chromium may be reduced or even eliminated from the filler wire 116.

[0203] In one or more embodiments, the filler wire 116 may include other elements such as the alloying elements in the base material (Usibor®) that promote hardenability of the weld joint 114 along with nickel and chromium.

[0204] In one or more embodiments, the percentage weight of nickel in the filler wire 116 is between 51.10 and 63.90%. In one or more embodiments, the percentage weight of nickel in the filler wire 116 is between 0 and 63.90%. In one or more embodiments, the percentage weight of chromium in the filler wire 116 is between 7.20 and 16.00%. In one or more embodiments, the percentage weight of chromium in the filler wire 116 is 19%. In one or more embodiments, the percentage weight of chromium in the filler wire 116 is between 7.20 and 24.00%.

[0205] In one or more embodiments, the percentage of nickel in the filler wire 116 is between 1.68 and 2.85%. In one or more embodiments, the percentage of chromium in the filler wire 116 is between 0 and 2.7%. In one or more embodiments, the percentage of chromium in the filler wire 116 is between 0.49 and 0.83%. In one or more embodiments, the percentage of chromium in the filler wire 116 is between 0.49 and 0.95%. In one or more embodiments, the percentage of chromium in the filler wire 116 is between 0.49 and 1.00%.

[0206] In one or more embodiments, the filler wire 116 material includes nickel based steel alloy, for example, Hastelloy C267. In one or more embodiments, the Hastelloy C267 material has 57% of Ni and 16% of Cr.

[0207] In one or more embodiments, the filler wire 116 material includes 4340 wire. In one or more embodiments, the 4340 wire material includes 1.8% nickel and 0.78% chromium.

[0208] In another embodiment, the percentage of nickel in the filler wire 116 is between 7.80 and 10.40%. In another embodiment, the percentage of chromium in the filler wire 116 is between 2.10 and 2.70%.

[0209] In yet another embodiment, the percentage of nickel in the filler wire 116 is between 2.72 and 4.63%. In yet another embodiment, the percentage of chromium in the filler wire 116 is between 0.72 and 1.22%.

[0210] In one or more embodiments, the carbon content in the filler wire 116 is between 0% and 0.59%. In one or more embodiments, the carbon content in the filler wire 116 is between 0.91% and 2.00%. In one or more embodiments, the carbon content in the filler wire 116 is created prior to drawing the filler wire 116. In one or more embodiments, the filler wire 116 includes a gradient of diffused carbon therein. In one or more embodiments, the filler wire 116 undergoes a carburizing process. In one or more embodiments, the carbon content is added using a carburizing process on an already drawn filler wire. In one or more embodiments, the carburizing process is configured to diffuse the carbon into the filler wire 116. In one or more embodiments, the carbon is added in any other alternate process / procedure that would be appreciated by one skilled in the art.

[0211] In one or more embodiments, the filler wire 116 may include up to 1% weight of carbon. In one or more embodiments, the filler wire 116 may include from 0.35 to 0.80 % weight of carbon. In one or more embodiments, the filler wire 116 may include from 0.35 to 0.90 % weight of carbon. In one or more embodiments, the carbon present in the filler wire 116 may have an impact on hardness and microstructure. In one or more embodiments, the carbon present in the filler wire 116 may substantially help the metallurgy.

[0212] In one or more embodiments, the Manganese (Mn) content in the filler wire 116 is between 0% and 0.29%. In one or more embodiments, the Manganese content in the filler wire 116 is between 0.3% and 0.9%. In one or more embodiments, the Manganese content in the filler wire 116 is between 0.91% and 2%.

[0213] In one or more embodiments, a method of cutting the workpieces 106, 108 may affect the desired, but non-limiting, chemical composition of the filler material. In one or more embodiments, the preparation of the edges of the workpieces 106, 108 may affect the desired, but non-limiting, chemical composition of the filler material. In one or more embodiments, the trim type of the parts / edges may affect the desired, but non-limiting, chemical composition of the filler material. In one or more embodiments, the edges of the workpieces 106, 108 are prepared by laser cutting. In another embodiment, the edges of the workpieces 106, 108 are prepared by shear cutting. In one or more embodiments, the edges are machined. For example, in one or more embodiments, the chemical composition of the filler material used for the laser cut edges may be different than the chemical composition of the filler material used for the sheared edges.

[0214] In one or more embodiments, the nickel in the filler wire 116 is configured to bind with the aluminum in the aluminum based coating 118, while the chromium in the filler wire 116 is configured to harden the weld for improved mechanical performance.

[0215] In one or more embodiments, the filler wire 116 may include 4340 chromemolybdenum low alloy wire. In one or more embodiments, the filler wire 116 may include carburized 4340 wire. The filler wire 116 may be stainless steel based filler wire.

[0216] In various contemplated embodiments, different, specifically-formulated chemical compositions of the filler wire 116 are utilized. For example, the chemical composition of the filler wire 116 may contain Nickel (Ni) and at least one of Carbon (C), Silicon (Si), Manganese (Mn), Phosphorous (P), Sulfur (S), Chromium (Cr), or Molybdenum (Mo). In one or more embodiments, the C content in the filler wire 116 is 0-1.5%, the Si content in the filler wire 116 is 0-3%, the Mn content in the filler wire 116 is 0-2.5%, the P content in the filler wire 116 is 0-0.05%, the S content in the filler wire 116 is 0-0.03%, the Ni content in the filler wire 116 is 6-22%, the Cr content in the filler wire 116 is 16-30%, and the Mo content in the filler wire 116 is 0-4%. A remainder of the filler wire may comprise or consist of Iron (Fe), trace elements, and impurities.

[0217] In one or more embodiments, the filler wire 116 material includes carburized wire. In an example, a carburized 4340 wire material includes 1.3% Carbon, 0.78% Chromium, 0.85% Manganese, 0.25% Molybdenum, 1.8% Nickel, 1.8% Silicon, 0.011% Phosphorus, and 0.014% Sulfur, the percentages being by weight. A remainder of the filler wire may comprise or consist of Iron (Fe), trace elements, and impurities.

[0218] In one or more embodiments, the filler wire 116 material is a stainless steel including e.g., Ni, Cr, or C.

[0219] According to the present disclosure, the filler wires including, e.g., Ni, or C within the disclosed ranges discussed herein, act as an austenite stabilizing element. As such, a ferrite microstructure formation is prevented or reduced in the weld joint 114 at temperatures ranging from 900°C to 950°C. Weld joints 114 having austenitic microstructure or ferritic microstructure may cause cracking in the weld, have less tensile strength than the workpieces being welded, create granular weld, or create other weld related issues.

[0220] According to one or more embodiments, the filler wire 116 has the following composition: carbon concentration ofo greater than or equal to 0.0001%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.14%, 0.15%, 0.2%, 0.25%, 0.3%, 0.4% and / or 0.45%; o less than or equal to 1.0%, 0.75%, 0.5%, 0.45%, 0.40%, 0.38%, 0.3%, 0.25%, 0.2%, 0.15%, 0.10%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, and / or 0.02%; and / or o between any two such lower and upper values (e.g., 0.0001% < C < 0.5%; 0.15% < C < 0.25%; 0.15% < C < 0.38%; 0.15% < C < 0.4%; 0.0001% < C < 1.0%, 0.001%< C < 0.03%; 0.001%< C < 0.45%; 0.0001% < C < 0.59%; 0.01%< C < 0.05%; 0.25%< C < 0.45%; 0.27% < C < 0.31%; 0.34% < C < 0.40%; 0.35% < C < 0.80%; 0.35% < C < 0.90%; 0.0001% < C < 1.0%);• manganese concentration of: o greater than or equal to 0%, 0.0001%, 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10%, 12.5%, 15%, 17.5%, 20%, and / or 25%; o less than or equal to 30%, 25%, 20%, 17.5%, 15%, 12.5%, 10%, 9.0%, 8.0%, 7.0%, 6.0%, 5.0%, 4.0%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05%, 0.01%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Mn < 30%; 0% < Mn < 3.0%; 0.001% < Mn < 5.0%; Mn 0.1% < Mn < 5.0%; 0.5% < Mn < 2.0%; 0.8% < Mn < 1.8%; 0.4% < Mn < 3%; 0.0001% < Mn < 30%; 0.0% < Mn < 0.29%; 0.15% < Mn < 0.60%; 0.3% < Mn < 0.9%; 0.82% < Mn < 0.87%; 0.91% < Mn < 2.0%; 1.0% < Mn < 2.5%);• silicon concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, and / or 0.5%; o less than or equal to 2.0%, 1.5%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05%, and / or 0.01%; and / oro between any two such lower and upper values (e.g., 0.0% < Si < 2%; 0.001% < Si < 1%; 0.01% < Si < 1.0%; 0.1% < Si < 1.0%; 0.0001%< Si< 1%; 0.1% < Si < 0.2%; 0.15% < Si < 0.40%; 0.30%< Si< 0.65%);• nickel concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.25%, 0.5%, 0.75%, 1.0%, 1.5%, 1.68%, 2.0%, 2.72%, 3.0%, 3.5%, 4.0%, 5.0%, 6.0%, 7.0%, 7.8%, 8.0%, 9.0%, 10%, 11.0%, 12.5%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 51.1%, 55%, and / or 60%; o less than or equal to 65%, 63.9%, 60%, 56%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 17.5%, 15%, 14.0%, 12.5%, 10.4%, 10%, 9.0%, 8.0%, 7.8%, 7.0%, 6.0%, 5.0%, 4.63%, 4.5%, 4.0%, 3.0%, 2.85%, 2.0%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper limits (e.g., 0.0% < Ni < 65%; 0.0% < Ni < 63.9%; 0.0% < Ni < 0.15%; 0.0% < Ni < 0.1%; 0.0001%< Ni < 63.9%; 0.0001% < Ni < 56%; 1.68% < Ni < 2.85%; 2.72% < Ni< 4.63%; 3.5% < Ni < 4.5%; 7.80% < Ni < 10.40%; 11.0% < Ni < 14.0%; 51.1% < Ni < 63.9%; Ni ~ 57%);• chromium concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.2%, 0.25%, 0.49%, 0.5%, 0.72%, 0.75%, 0.95%, 1.0%, 1.5%, 1.6%, 2.0%, 2.1%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 6.0%, 7.0%, 7.2%, 7.8%, 8.0%, 9.0%, 10%, 11.0%, 12.5%, 15%, 18%, 20%, and / or 25%; o less than or equal to 30%, 25%, 24%, 20%, 17.5%, 16%, 15%, 12.5%, 10%, 9.0%, 8.0%, 7.0%, 6.0%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.7%, 2.5%, 2.0%, 1.5%, 1.22%, 1.0%, 0.9%, 0.83%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%,0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Cr < 30%; 0.0001% < Cr < 30%; 0.0% < Cr < 2.70%; 0.1% < Cr < 0.2%; 0.49% < Cr < 0.83%; 0.49% < Cr < 0.95%; 0.49% < Cr < 1.00%; 0.72% < Cr < 1.22%; 1.6% < Cr < 2.0%; 2.10% < Cr < 2.70%; 7.20% < Cr < 24.0%; 18% < Cr < 20%; 7.20% < Cr < 16.00%; Cr ~ 19%; Cr ~ 0.78%);• molybdenum concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and / or 4.5%; o less than or equal to 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Mo < 5.0%; 0.3% < Mo < 0.6%; 2.0%< Mo< 3.0%);• phosphorus concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%; o less than or equal to 0.3%, 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.025%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < P < 0.30%; 0.0% < P < 0.1%; 0.0% < P < 0.025%);• sulfur concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%; o less than or equal to 0.3%, 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.025%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / oro between any two such lower and upper values (e.g., 0.0% < S < 0.30%;0.0% < S < 0.1%; 0.0001% < S < 0.025%; 0.0% < S < 0.30% (e.g.,0.0% < S < 0.03%; 0.0% < S < 0.05%);• aluminum concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, and / or 0.3%; o less than or equal to 0.4%, 0.3%, 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Al < 0.4%; 0.0% < Al < 0.1%; 0% < Al < 0.07%; 0% < Al < 0.05%; 0.01% < Al < 0.4%; 0.01% < Al < 0.1%; 0.001% < Al < 0.1%; 0.01% < Al < 0.07%; 0.0001% < Al < 0.30%);• copper concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%; o less than or equal to 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%. 0.9%, 0.8%, 0.75%, 0.7%, 0.6%. 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper limits (e.g., 0.0% < Cu < 1.8%; 0.0001% < Cu < 1.80%);• niobium concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.01%, 0.015%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, and / or 1.4%; o less than or equal to 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%. 0.9%, 0.8%, 0.7%, 0.6%. 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%,0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Nb < 1.5%; 0.0001% < Nb < 1.50%; 0.0% < Nb < 0.15%; 0.0% < Nb < 0.1%; 0.001% < Nb < 0.2%; 0.01% < Nb < 0.2%; 0.015% < Nb < 0.100%);• titanium concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.2%, and / or 0.25%; o less than or equal to 0.3%, 0.2%, 0.18%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Ti < 0.3%; 0.001% < Ti < 0.30%; 0.0% < Ti < 0.1%);• nitrogen concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.015%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.2%, 0.25%, 0.49%, 0.5%, 0.72%, 0.75%, 0.95%, 1.0%, 1.5%, 1.6%, 2.0%, 2.1%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 6.0%, 7.0%, 7.2%, 7.8%, 8.0%, and / or 9.0%; o less than or equal to 10%, 9.0%, 8.0%, 7.0%, 6.0%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.7%, 2.5%, 2.0%, 1.5%, 1.22%, 1.0%, 0.9%, 0.83%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper limits (e.g., 0.0% < N < 10%; 0.0001% < N < 10%; 0.001% < N < 10%; 0.0% < N < 0.01%; 0.0% < N < 0.009%; 0.003% < N < 0.010%; ~ 0.005%);• vanadium concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;o less than or equal to 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.025%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < V < 0.10%; 0.0001%< V< 0.1%; 0.001% < V < 0.1%);• cobalt concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%; o less than or equal to 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.025%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < Co < 0.20%; 0.0001%< Co < 0.2%; 0.001% < Co < 0.2%); and / or• boron concentration of: o greater than or equal to 0.0%, 0.0001%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%; o less than or equal to 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.025%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or o between any two such lower and upper values (e.g., 0.0% < B < 0.10%; 0.0001%< B < 0.1%; 0.001% < B < 0.1%).According to various non-limiting embodiments, a remainder of the composition of the filler wire 116 comprises or consists of iron, trace elements, and impurities.

[0221] According to one or more embodiments, a composition of the filler wire 116 comprises:• 0.001% < C < 0.45%;• 0.001% < Mn < 30%;• 0.001%< Si< 1%;• 0.001% < Ni < 56%;• 0.001% < Cr < 30%;0.001%< Mo< 5%;• 0.001% < Al < 0.30%;• 0.001% < Cu < 1.80%;• 0.001% < Nb < 1.50%;• 0.001% < Ti < 0.30%;• 0.001%< N< 10%;• 0.001%< V< 0.1%; and• 0.001% < Co < 0.20%.According to various non-limiting embodiments, a remainder of the composition of the filler wire 116 comprises or consists of iron, trace elements, and impurities.

[0222] According to one or more embodiments, a composition of the filler wire 116 comprises:• 0.27% < C < 0.31%;• 0.82% < Mn < 0.87%;• 0.1% < Si < 0.2%;• 0.1% < Cr < 0.2%; and / or• 0.002% < B < 0.005%.According to various non-limiting embodiments, a remainder of the composition of the filler wire 116 comprises or consists of iron, trace elements, and impurities.

[0223] According to one or more embodiments, a composition of the filler wire 116 comprises:• 0.34% < C < 0.40%;• 0.15% < Mn < 0.60%;• 0.15% < Si < 0.40%;• 1.6% < Cr < 2.0%;• 0.3% < Mo < 0.6%;• 3.5% < Ni < 4.5%; and / orB < 0.015%According to various non-limiting embodiments, a remainder of the composition of the filler wire 116 comprises or consists of iron, trace elements, and impurities.

[0224] According to various embodiments, the filler wire 116 has a circular cross-section with a diameter that is (a) at least 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.2, 2.6, 2.8, 3.0. 3.2, 3.4, 3.6, 3.8, and / or 4.0 mm, (b) less than or equal to 5.0, 4.5, 4.0, 3.8, 3.6, 3.4, 3.2, 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, and / or 0.06 mm, and / or (c) between any two such values (e.g., 0.6-5.0 mm, 1.0-4.0 mm, 0.6-1.0 mm, 0.8-1.2 mm, ~0.8 mm, - 0.9 mm, - 1.0 mm, etc.). The thickness of the filler wire 116 may be commonly specified by a traditional, non-linear measure known as its gauge. For example, the larger the gauge number, the thinner the filler wire 116 is. The gauge of the filler wire 116 may be in the range between 0.8 and 0.9mm. The gauge of the filler wire 116 may be in the range between 0.6 and 1.2mm. In various embodiments, the width / thickness / gauge of the filler wire 116 may be configured to match with the width of the laser beam 120.

[0225] According to various non-limiting embodiments, the primary alloying constituents of the filler wire 116 (e.g., stainless steel 316L) after iron, are chromium (between 16 and 20%), nickel (10 and 14%) and molybdenum (2 and 3%), while small (less than 1%) quantities of silicon, phosphorus, and sulfur may also present. The addition of molybdenum may provide greater corrosion resistance than stainless steel 304, with respect to localized corrosive attack by chlorides and to general corrosion by reducing acids, such as sulfuric acid.

[0226] The filler wire 116 may be a flux core filler wire. The filler wire 116 may be a metal core filler wire, that is, the filler wire 116 is a hollow core filler wire with metal powder in the hollow core of the filler wire 116.

[0227] The filler wire 116 may be a coated wire. The filler wire 116 may include a boron alloyed steel (e.g., 22MnB5) filler wire that is coated with nickel chromium coating.

[0228] In various embodiments, instead of the filler wire 116, a powder additive may be deposited using a laser metal deposition (LMD) on the steel workpieces 106, 108 before the welding procedure. According to various embodiments, the filler powder may have the same or similar composition as any of the filler wires 116 disclosed herein. In various embodiments, a laser-cladding procedure may be performed in which a clad layer of an alloying material is formed along a future weld joint 114 within the interface 112 between facing edges of the steel workpieces 106, 108. The laser-cladding procedure may generally be followed by a laserwelding procedure in which the alloying material from the clad layer is mixed into the melt pool. In another embodiment, an alloying material, in powdered form, may be directed into amelt pool that is formed when steel workpieces 106, 108 are being laser welded together. For example, U.S. Patent No. 10,052,720B2 discloses a process for laser welding together sheet metal plates, which are pre-coated with an aluminum based layer using powder additive, the entire contents of which are incorporated herein by reference.

[0229] In various embodiments, the filler wire 116 has a higher carbon content than one or both of the work pieces 106, 108. Depending on the relative weight-based ratios of the filler wire 116 and the workpieces 106, 108 in the weld joint 114, the weld joint 114 formed may include higher carbon content than one or both workpieces 106, 108. In such an embodiment, a filler wire having higher carbon content may be used to achieve this higher carbon content of the weld joint 114. For example, a copper / copperized filler wire 116 having a higher carbon content may be used to provide a weld joint 114 with higher carbon content.

[0230] In an alternative embodiment, the filler wire 116 has a lower carbon content than one or both of the workpieces 106, 108. Depending on the relative weight-based ratios of the filler wire 116 and the workpieces 106, 108 in the weld joint 114, the weld joint 114 may have a lower carbon content than one or both of the work pieces 106, 108.

[0231] In one or more embodiments, in addition to the effects on the weld, the filler wire 116 is also configured to reduce the manufacturing costs of laser welding aluminum coated boron steel blanks. First, if the addition of the metallurgical additive in the form of the filler wire 116 sufficiently neutralizes the aluminum-silicon coating, a laser ablation procedure (e.g., as shown discussed in the prior art method in the background section of the present patent application and / or discussed herein) may be skipped according to one or more embodiments. This would save costs on the capital investments in the laser ablation equipment and manufacturing costs by eliminating the requirement for a W.I.P. (work in progress).

[0232] Secondly, with the addition of the metallurgical additive in the form of the filler wire 116, the tolerance on the weld gap at the interface 112 will be larger, meaning that a fine blanking press may not be required. This may save additional capital costs because a conventional blanking press can be used.

[0233] Lastly, since the addition of the metallurgical additive in the form of the filler wire 116 is a more robust process / procedure that is configured to fill in undercuts, it could reduce the scrap rate of the process / procedure.

[0234] According to various non-limiting embodiments, any of the workpieces 106, 108 and welding systems disclosed herein may be used with any of the filler wires 116 discussed herein,any of the filler powders discussed here, or no filler material at all (e.g., wherein the weld joint 114 is formed entirely from the work pieces 106, 108).

[0235] In one or more embodiments of the method 500, the use of a filler wire 116, rather than a filler powder, provides a cleaner procedure or process. That is, there is no residual powder on the workpiece 106, 108 surface(s), on the floor, and / or tooling surface(s). In other words, the cleaner tooling surface(s), the cleaner part surface(s), and the cleaner floor are better for a production environment to keep the manufacturing cell cleaner and prevent powder from creating an unclean environment and potentially clogging the powder feeding system (e.g., tube and nozzle). However, according to other embodiments, a filler powder is used, e.g., where the benefits of using a filler powder outweigh potential downsides.

[0236] According to various non-limiting embodiments, the use of such filler wire 116 with sufficient Ni, Cr, and / or C results in a weld joint 114 with a higher strength (e.g., ultimate tensile strength (UTS)) than would have resulted from the use of no filler material or filler material with insufficient Ni, Cr, and / or C. In addition, according to various non-limiting embodiments, the use of such filler wire 116 with sufficient Ni, Cr, and / or C results in a weld joint 114 that is less prone to failure (e.g., break, cracks, etc.) during cooling or when loaded than if such filler wire 116 was not used. From spectroscopy (e.g., EDX) results for a weld joint 114 without using filler wire 116, aluminum is not well distributed or mixed in the weld and there is evidence of high concentration of aluminum areas. The microstructure of such a weld joint 114 also shows a substantial amount of ferrite mixed with martensite when the filler wire 116 is not used. For example, ferrite amounts to 10-70% by weight and martensite may amount to 30-90% by weight. As a result, the weld joint is brittle or has lower strength compared to the weld joint 114 formed using filler wires 116 discussed herein.

[0237] While certain embodiments utilize filler wire 116 (or a filler powder with the same or similar composition as the filler wires 116 described herein), the use of a filler wire 116 or filler powder may also be omitted without deviating from the scope of the present disclosure. In such non-filler embodiments, the weld joint 114 may be formed entirely from material in the parent workpiece(s) 106, 108.

[0238] According to various embodiments that involve cold-stamping, rather than hot- stamping, of the welded assembly 110, filler wire 116 may also be omitted. Additionally and / or alternatively, other types of filler wires with different compositions may be used for welded blanks designed for cold-stamping. In such cold-stamping embodiments, filler wire 116 may be used purely as a filler so as to avoid concave or underfilled weld joints. However, even insuch cold-stamping embodiments, the composition of the filler wire may be selected to improve the strength of the weld joint 114.

[0239] According to various embodiments, the filler wire 116 may have less carbon than one or both workpieces 106, 108, about the same amount of carbon as one or both workpieces 106, 108, or more carbon than one or both workpieces 106, 108.1. RELATIVELY LOW CARBON FILLER WIRE (E G., 316L STAINLESS STEEL)

[0240] According to one or more embodiments, Applicant discovered that a filler wire 116 with a stainless steel 316L grade (e.g., ER316L), or a similar composition, creates a strong weld joint 114 between: (a) high strength workpieces 106, 108, (b) low strength workpieces 106, 108, and / or (c) a high strength steel workpiece 106, 108 and a low strength steel workpiece 106, 108.

[0241] In various embodiments, the filler wire 116 may include stainless steel 316L wire. According to various embodiments, the filler wire 116 is a 316L stainless steel filler wire comprising 0-0.03% carbon, 18-20% chromium, 11-14% nickel, 2-3% molybdenum, 1-2.5% manganese, and 0.3-0.65% silicon. In a specific example, the 316L wire 116 material includes 0.03% Carbon, 17% Chromium, 2% Manganese, 2.5% Molybdenum, 12.5% Nickel, 0.75% Silicon, 0.045% Phosphorus, and 0.03% Sulfur, the percentages being by weight. A remainder of the composition of the filler wire 116 may comprise or consist of iron, trace elements, and impurities.

[0242] According to one or more embodiments, a composition of the filler wire 116 comprises: -0.022% C, -0.49% Si, -1.58% Mn, -0.028% P, -0.009 % S, -18.3 % Cr, -2.51 % Mo, - 11.1 % Ni, less than 0.01 % Al, 0.067% Co, - 0.13 % Cu, less than 0.005% Nb, less than 0.005% Ti, and -0.041% V.

[0243] According to one or more embodiments, a composition of the filler wire 116 comprises Hyundai ER316L having -0.011% C, -1.55% Mn, -0.013% P, -0.014 % S, -0.36% Si, -0.06% V, -0.05% Cu, - 64.8% Fe, -18.3 % Cr, - 12.18% Ni, -2.51 % Mo, less than 0.01 % Ti, less than 0.01% Nb, less than 0.01% Al, - 0.11% Co, and - 0.043% N.

[0244] According to one or more embodiments, a composition of the filler wire 116 comprises Hyundai SM-316L having - 0.02% C, - 0.39% Si, - 1.69% Mn, - 19.5% Cr, - 12.8% Ni, and - 2.5% Mo.

[0245] According to one or more embodiments, a composition of the filler wire 116 comprises: 0-0.03% C (e.g., -0.020% C), 0.30-0.65% Si (e.g., -0.4% Si), 1.3-2.0% Mn (e.g.,-1.8% Mn), 0-0.030% P (e.g., -0.015% P), 0.005-0.020% S (e.g., -0.015% S), 18.0-20.0% Cr (e.g., -18.5% Cr), 11.0-13.0% Ni (e.g., - 12% Ni), 2.5-3.0% Mo (e.g., -2.7 % Mo), 0-0.5% Cu (e.g., - 0.1% Cu), and 0-0.080% N.

[0246] According to one or more embodiments, a composition of the filler wire 116 (e.g., ER316L) comprises: 0-0.03% C (e.g., -0.020% C), 18.0-20.0% Cr (e.g., -18.7% Cr), 11.0- 14.0% Ni (e.g., - 11.6% Ni), 2.0-3.0% Mo (e.g., -2.3 % Mo), 1.0-2.5% Mn (e.g., -1.8% Mn), 0.30-0.65% Si (e.g., -0.51% Si), 0-0.030% P (e.g., -0.015% P), 0.000-0.03% S (e.g., -0.015% S), and 0-0.75% Cu (e.g., - 0.08% Cu).

[0247] According to one or more embodiments, the filler wire 116 may comprise Lincolnweld® 316 / 316L stainless steel filler wire or a comparable filler wire from another manufacturer (e.g., Messer).

[0248] The stainless steel 316L grade filler wire is the low carbon version of 316 stainless steel. The filler wire 116 may include stainless steel based 316L filler wire. The filler wire 116 may include stainless steel alloy 316L filler wire. The filler wire 116 may include silicon stainless steel 316L filler wire. The filler wire 116 may include magnesium stainless steel 316L filler wire.

[0249] According to one or more embodiments, the filler wire 116 may comprise carburized 4340 with about 0.1% carbon (e.g., Ni / Cr ratio of about 2.33, Cr of about 0.78%, Ni of about 1.8%, Mo of about 0.25%, Mn of about 0.85%, and C of about 1.3%)..2. RELATIVELY HIGH CARBON (E G., SS330, ER330) FILLER WIRE USED TO LASER WELD HIGH TO LOW STRENGTH WORKPIECES

[0250] According to one or more embodiments, Applicant discovered that a filler wire 116 with a stainless steel composition (e.g. SS330, ER 330 (e.g., from Lincoln Electric)), or a similar composition, creates a strong weld joint 114 between a high strength steel workpiece 106, 108 and a low strength steel workpiece 106, 108. In tensile strength tests conducted by Applicant on samples of a high strength steel workpiece (specifically Usibor 1500) welded to a low strength steel workpiece (specifically Ductibor 500) using SS330 filler wire, all of the samples broke on the Ductibor 500 portion of the test sample, which shows that the weld joint 114 was stronger than the Ductibor 500 portion, and provided a strong, effective joint 114.

[0251] In one or more embodiments, the filler wire 116 (e.g., SS330 or similar) has the following composition:• C: at least 0, 0.1, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, and / or 0.21%; at most 0.4, 0.3, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, and / or 0.23%; 0.1%<C<0.3%; 0.15%<C<0.28%; 0.17%<C<0.27%; 0.18%<C<0.25%; and / or 0.23%.• Cr: e.g.: at least 10, 11, 12, 13, and / or 14%; at most 40, 30, 25, 20, 19, 18, and / or 17%; 10%<Cr<40%; 10%<Cr<30%; 10%<Cr<20%; 14%<Cr<18%; 15%<Cr<17%; and / or 15.9%;• Ni: e.g.: at least 10, 15, 20, 25, 30, and / or 32%; at most 50, 45, 40, and / or 38%; 10%<Ni<50%; 25%<Ni<45%; 30%<Ni<40%; 34%<Ni<37%; and / or 35.2%;• Mo: e.g.: at least 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and / or 0.7%; at most 5, 4, 3, 2, 1, 0.9, and / or 0.8%; 0%<Mo<5.0%; 0%<Mo<1.0%; 0.5%<Mo<1.0%; 0%<Mo<0.75%; and / or 0.75%;• Mn: e.g.: at least 0, 0.5, 1.0, 1.5, 1.6, 1.7, and / or 1.8%; at most 5, 4, 3, and / or 2.5%; 0%<Mn<5%; l%<Mn<3%; l%<Mn<2.5%; 1.5%<Mn<2.5%; and / or 1.9%;• Cu: at least 0, 0.1, 0.2, 0.3, 0.4, 0.5, and / or 0.6%; at most 5.0, 4.0, 3.0, 2.0, 1.0, 0.9, and / or 0.8%; 0%<Cu<5%; 0.01%<Cu<1.0%; 0%<Cu<0.75%; 0.02%<Cu<0.0.05%; and / or 0.03%.According to various of these embodiments, the filler wire 116 also comprises iron, trace elements, and impurities (e.g., 0%<P<0.03%; 0%<S<0.03%). According to various of these embodiments, a remainder of the composition of the filler wire 116 consists of iron, trace elements, and impurities. According to various embodiments, Ni and / or Mn may be eliminated from the filler wire 116. According to various embodiments, Cr, Ni, and / or Mn may be eliminated from the filler wire 116. According to one or more embodiments, other elements (e.g., Si, Cu, N, Al, Nb, Ti, B, and / or V) may be added to the filler wire 116.

[0252] For example, the ER330 filler wire 116 may comprise: 0.18-0.25% C, 15.0-17.0% Cr, 0-0.75% Cu, 1.0-2.5% Mn, 0-0.75% Mo, 34.0-37.0% Ni, 0-0.03% P, 0-0.03% S, and 0.30- 0.65% Si. The ER330 filler wire 116 may typically comprise 0.19-0.21% C, 15.8-16.1% Cr, 0.02-0.05% Cu, 1.6-1.8% Mn, 0.06-0.07% Mo, 0.01-0.03% N, 0.01-0.19% Nb, 35.0-35.5% Ni, 0.01% P, <0.003% S, and 0.41-0.49% Si.

[0253] According to various embodiments, a carbon content of the filler wire 116 is similar to the carbon content of the high strength steel workpiece 106, 108. According to various embodiments, a carbon content of the filler wire 116 is higher than a carbon content of the high strength steel workpiece 106, 108, e.g., by (a) at least 0.01, 0.02, 0.03, 0.04, and / or 0.05%C (in absolute terms), (b) less than 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, and / or 0.03% C, and / or (c)by an amount between any two such values (e.g., by between 0.01 and 0.1% C). According to various alternative embodiments, a carbon content of the filler wire 116 is lower than a carbon content of the high strength steel workpiece 106, 108, e.g., by (a) at least 0.01, 0.02, 0.03, 0.04, and / or 0.05% C (in absolute terms), (b) less than 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, and / or 0.03% C, and / or (c) by an amount between any two such values (e.g., by between 0.01 and 0.1% C). For example, in various embodiments, the carbon content of the filler wire 116 was 0.21% C and the carbon content of the high strength steel workpiece 106, 108 was 0.23% C, such that the carbon content of the filler wire 116 was lower than the carbon content of the high strength steel workpiece 106, 108 by 0.02% C.

[0254] According to various alternative embodiments, the high carbon filler wire 116 (e.g., SS330) is used to laser weld together: (1) a high strength workpiece 106, 108 to a low strength workpiece 106, 108, (2) two high strength workpieces 106, 108, or (3) two low strength workpieces 106, 108.

[0255] According to various embodiments in which filler wire 116 is used to weld a high strength steel workpiece 106, 108 to a low strength steel workpiece 106, 108, a carbon content of the filler wire 116 is higher than a carbon content of the resulting weld joint 114, e.g., by (a) at least 0.01, 0.02, 0.03, 0.04, and / or 0.05% C (in absolute terms), (b) less than 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, and / or 0.03 %C, and / or (c) by an amount between any two such values (e.g., by between 0.01 and 0.1% C). For example, in various embodiments, the carbon content of the filler wire 116 is 0.21% C and the carbon content of the weld joint 114 is 0.16% C, such that the carbon content of the filler wire 116 is higher than the carbon content of the weld joint 114 by 0.05% C.

[0256] According to various embodiments in which filler wire 116 is used to weld a high strength steel workpiece 106, 108 to a low strength steel workpiece 106, 108, a carbon content of the filler wire 116 is lower than a carbon content of the resulting weld joint 114, e.g., by (a) at least 0.01, 0.02, 0.03, 0.04, and / or 0.05% C (in absolute terms), (b) less than 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, and / or 0.03% C, and / or (c) by an amount between any two such values (e.g., by between 0.01 and 0.1% C).

[0257] According to various embodiments in which filler wire 116 is used to weld a high strength steel workpiece 106, 108 to a low strength steel workpiece 106, 108, a carbon content within the weld joint 114 is (a) at least 0.15, 0.151, 0.16, and / or 0.17%, (b) at most 0.22, 0.21, 0.20, 0.19, 0.18, and / or O.17%; and / or (c) between any two such values (e.g., 0.15%<C<0.25%; 0.151%<C<0.2%).

[0258] According to various embodiments in which filler wire 116 (e.g., SS330) is used to weld a high strength steel workpiece 106, 108 (e.g., 0.8 mm thick Usibor 1500 comprising 0.221% C, 1.211% Mn, 0.258% Si, 0.19% Cr, 0.036% Al, 0.003% S, 0.019% P, 0.039% Ti, with a remainder comprising Fe and impurities and a 0.03 mm thick coating on each side comprising 90% Al and 10% Si) to a low strength steel workpiece 106, 108 (e.g., 0.8 mm Al- coated Ductibor 500 comprising 0.059% C, 1.646% Mn, 0.022% Si, 0.016% Ni, 0.027%Cr, 0.024% Al, 0.003% Mo, 0.004% S, 0.016% P, 0.048% Nb, 0.067% Ti, 0.005% N, 0.009% Cu, and 0.003% Ca and a 0.03 mm thick coating on each side comprising 90% Al and 10% Si), the resulting composition of the weld joint 114 is: 0.16% C, 1.5% Mn, 0.3% Si, 8.5% Ni, 3.9% Cr, 1.7% Al, 0.2% Mo, 0.0025% S, 0.013% P, 0.018% Nb, 0.039% Ti, 0.002% N, 0.003% Cu, and 0.001% Ca.

[0259] According to various embodiments, when using the softening factor (FA) formula in U.S. Patent No. 11,945,503 and the mean / average elemental composition of the weld joint 114, the softening factor of the weld joint 114 according to one or more embodiments disclosed herein is less than 5000 (e.g., less than 5000, 4500, 4000, 3500, 3000, 2500, 2000, 1500, and / or 1000 (e.g., 941)), yet still produces a strong weld joint 114 with a carbon content of at least 0.15% (e.g., 0.16%). These results are contrary to what was understood in the art from, for example, U.S. Patent No. 11,945,503’s disclosure that a strong joint required a softening factor of over 5000 if the carbon content of the weld joint 114 is at least 0.15% (criterion C3).C. WELDING METHOD AND APPARATUS

[0260] FIGS. 1-2 and 6-7 show a method 500 for using the laser welder 102 for laser welding the workpieces 106, 108 to form a welded assembly 110 in accordance with one or more embodiments of the present application.1. Workpiece Edges And Positioning

[0261] The laser welder 102 may be configured to weld the first steel workpiece 106 to the second workpiece 108 along an interface 112 between edges and / or surfaces of the first and second steel workpieces 106, 108 to form the welded assembly 110. In one or more embodiments, the method 500 comprises positioning (e.g., procedure 502 as shown in FIG. 1) the workpiece 106 and the at least one additional workpiece 108 together to form the interface 112 therebetween. According to various embodiments, the interface 112 may be shaped and positioned to facilitate any desired type of weld joint 114 (e.g., lap joints, butt joints, T-joints, corner joints or edge joints, patch joints).

[0262] The butt weld joints 114 may include square groove, single bevel groove, double bevel groove, single J groove, double J groove, single V groove, double V groove, single U groove, or double U groove between the two steel workpieces 106, 108. The corner weld joints 114 may include V-groove, J-groove, U-groove, spot, edge, fillet, comer-flange, bevel-groove, fl are- V-groove and square-groove or butt between the two steel workpieces.

[0263] The lap weld joints 114 are essentially a modified version of the butt weld joint 114. They are formed when two steel workpieces are placed in an overlapping pattern on top of each other. They are most commonly used to joint two steel workpieces with differing thicknesses together. Welds can be made on one or both sides.

[0264] The edges and / or surfaces of the workpieces 106, 108 to be welded may be shaped and positioned so that the resulting weld joint 114 and weld formed between the two steel workpieces 106, 108 has a linear or a straight line configuration. The weld joint 114 and weld formed between the two steel workpieces 106, 108 may have a non-linear or a non-straight line configuration. For example, the weld joint 114 and weld formed between the two steel workpieces 106, 108 may have a wavy shaped configuration, an elliptical shaped configuration, a circular shaped configuration, a C-shaped configuration, a S-shaped configuration, a zigzag shaped configuration, any shaped configuration that may not define for a straight line, etc. According to various embodiments, a non-linear seam may increase the strength of the overall weld joint 114 by increasing the effective weld joint length relative to a straight line.

[0265] The trimming and / or cutting procedures may be performed on the two steel workpieces 106, 108 prior to the welding procedure to prepare the edges of the two steel workpieces 106, 108 that are welded together. That is, the cutting procedure (e.g., shaped steel workpiece(s) with desired edge shape) may be performed before the welding procedure. A trimming and / or cutting procedure may be additionally and / or alternatively be performed on the weld assembly after the welding procedure but before the hot stamping procedure (e.g., to trim the edges of the welded blank). However, such trimming and / or cutting procedures (either before the welding procedure and / or between the welding procedure and hot stamping) may be omitted. Additionally and / or alternatively, trimming and / or cutting procedures may be performed on the hot formed / stamped weld assembly after the hot stamping procedure but before any other post processing procedures.

[0266] Various forming processes for the edges to be welded result in a burr side and a nonburr side of the edge of the workpiece 106, 108. According to various embodiments, the workpieces 106, 108 may be positioned for welding such that: (a) the burr side of the workpiece106 is up while the burr side of the workpiece 108 is down, (b) the burr sides of both workpieces 106, 108 are up, or (c) the burr sides of both workpieces 106, 108 are down.

[0267] According to various embodiments, one of the workpieces 106, 108 is pushed toward the other workpiece 106, 108 (e.g., via pneumatic or electric actuators) so as to reduce and / or minimize any local gaps at the interface 112 prior to and / or during the welding operation. According to various embodiments, the workpieces 106, 108 are pushed together such that they contact each other at one or more locations along the interface 112 and are held in this position during the welding operation. As a result, there is not an interface-long gap between the workpieces 106, 108. However, there may be locations along the interface 112 where there are local gaps between the workpieces 106, 108. The local gap(s) may range between 0.01 and 0.2 mm over the length of the interface 112. According to various embodiments, the largest local gap between the workpieces 106, 108 over the length of the interface 112 may be less than or equal to 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.15 mm, and / or 0.1 mm.

[0268] According to various embodiments, an absolute gap is present over the entire length of the interface such that that the local gap over the length of the interface is always greater than 0.0, 0.05, 0.10, 0.15, 0.20, and / or 0.25 mm. According to various embodiments, such intentional gap provides space for the filler wire 116 to become part of the weld joint 114 without causing excess overfill. Inclusion of filler wire 116 material in the weld joint 114 may improve the strength of the weld joint 114.

[0269] In one or more embodiments, the workpieces 106, 108 are held on a worktable prior to the laser weld procedure and during the laser weld procedure to maintain the relative positions of the workpieces 106, 108 prior to and during the welding process, for example, as disclosed in PCT Publication No. WO / 2022 / 213219.2. Clamp-Cut-And-Weld

[0270] According to various non-limiting embodiments, the edge of one or both workpieces 106, 108 to be welded may be formed by cutting (e.g., laser cutting) before being welded. According to various embodiments, the laser welder 102 is used both for laser cutting the edge(s) to be welded and for laser welding. According to alternative embodiments, separate cutting and welding lasers are used. According to one or more embodiments, the edge(s) may be cut after the workpiece(s) 106, 108 are clamped in place. After the edge(s) are cut, the workpieces 106, 108 may remain clamped and moved toward one another (e.g., by moving one or both of the clamped workpieces 106, 108) so as to precisely position the edges to be welded relative to each other along the interface 112. According to various non-limiting embodiments,the clamped workpieces 106, 108 are moved toward each other such that the edges to be welded contact each other at at least one location along their interface 112. This clamp, cut, move, and weld procedure may be performed, for example, in the manner described in EP 0 326 994 Al or PCT Publication No. WO / 2022 / 213219.

[0271] According to various embodiments, the workpieces 106, 108 may be clamped into position using any suitable type of clamps (e.g., mechanical, electromagnetic, and / or vacuumbased clamp(s)). According to various embodiments, a combination of vacuum-based and electromagnetic claims are used to securely hold the workpieces 106, 108 in position. According to various embodiments, vacuum -based clamps (e.g., as part of workpiece 106, 108 transfer robots or systems) are used to initially position the workpieces 106, 108 on a jig, and then electromagnetic clamping is employed to secure the workpieces 106, 108 in place to form the interface 112.

[0272] According to various alternative embodiments, the workpieces 106, 108 are clamped, then one of the edges to be welded of just one of the workpieces 106, 108 is laser trimmed so as to match a profile of the mating edge of the other workpiece 106, 108. The workpieces 106, 108 are then moved toward each other and welded together. Exemplary embodiments of this clamp-cut-weld process are described in U.S. Provisional Application No. 63 / 643,947, titled “Method of Tracking A Blank Edge For Laser Cutting,” filed May 4, 2024, the entire contents of which are hereby incorporated herein by reference.3. Laser Welder and Laser Beam

[0273] In one or more embodiments, the laser welder 102 is configured to irradiate the laser beam 120 onto the interface 112 and workpieces 106, 108 to weld the workpieces 106, 108 to form the welded assembly 110.

[0274] As shown in FIG. 2, the laser welder 102 may be configured to generate the laser beam 120 to melt a portion of at least one of the workpieces 106, 108 at the interface 112. According to one or more embodiments, the laser welder 102 may be configured to use the laser beam 120 to melt a portion of both workpieces 106, 108 at the interface 112. As shown in FIG. 2, according to various embodiments, a beam axis (e.g., disposed centrally) of the laser beam 120 extends in the Z direction substantially perpendicular to the main surfaces of the first and second steel workpieces 106, 108, which extend along an X / Y plane. That is, the laser beam 120 is substantially perpendicular to and makes a 90 degree angle with the surfaces of the first and second steel workpieces 106, 108, which may help to more quickly melt the workpieces 106, 108 and speed up the welding process. A projection directi on / axis (Z) of thelaser beam 120 and the plane(s) of the workpieces 106, 108 may be perpendicular to each other. In other words, the laser beam 120 projects downwardly in a Z direction, while the main surfaces of the workpieces 106, 108 are in the X / Y plane. However, according to various alternative embodiments, the laser beam 120 may form an angle of less than 90 degrees with the surface(s) of the workpieces 106, 108. For example, an angle formed between the beam 120 and the surface(s) of the workpiece(s) 106, 108 may be (a) less than 90, 89, 88, 87, 86, 85, 80, 75, and / or 70 degrees, (b) more than 40, 45, 50, 55, 60, 65, 70, 75, 80, and / or 85 degrees, and / or between any two such values (e.g., between 40 and 89 degrees, between 80 and 89 degrees). According to various embodiments, the non-perpendicular angle may be used to control a rate and / or location at which laser energy is absorbed by the workpiece(s) 106, 108, filler wire 116, and / or melt pool.

[0275] The filler wire feed 104 may be configured to feed the filler wire 116 to the interface 112, when the first and second steel workpieces 106, 108 are being welded to each other to form the welded assembly 110, such that an axis (e.g., disposed centrally) of the filler wire 116 is at an angle with respect to the surfaces of the first and second steel workpieces 106, 108. According to various embodiments, the angle of the filler wire 116 with respect to the main (X / Y plane) surfaces of the first and second steel workpieces 106, 108 is (a) less than or equal to 60, 55, 50, 45, 40, 35, and / or 30 degrees, (b) at least 15, 20, 25, 30, 35, 40, 45, 50, 55, and / or 60 degrees, and / or between any two such values (e.g., between 15 and 60 degrees, between 30 and 50 degrees, between 35 and 45 degrees). According to various embodiments, the angle of the filler wire 116 with respect to the Z-axis laser beam 120 is (a) at least 30, 35, 40, 45, 50, 55, 60, and / or 65 degrees, (b) less than or equal to 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, and / or 15 degrees, and / or (c) between any two such values (e.g., between 30 and 85 degrees, between 40 and 60 degrees, between 45 and 55 degrees).

[0276] According to various embodiments, the filler wire feed 104 and laser beam 120 are positioned relative to each other and the workpieces 106, 108 such that laser beam 120 impinges (e.g., intersects) on the filler wire 116 above the surface of the work pieces 106, 108 and weld pool. According to one or more embodiments this may melt the filler wire 116 above the weld pool such that liquid filler wire 116 material falls into the weld pool. Alternatively, solid filler wire 116 may be fed into the melt pool and melted by the heat in the melt pool. As a result, the filler wire 116 is fed into the melt pool, either after being melted by the laser beam 120 and / or before being melted by heat within the melt pool.

[0277] In one or more embodiments, the laser welder 102 includes a direct diode laser. In another embodiment, the laser welder 102 includes a YAG laser. In yet another embodiment, the laser welder 102 includes a CO2 laser. In yet another embodiment, the laser welder 102 includes a fiber laser. The laser welder 102 may include an optical fiber laser manufactured by IPG Photonics. In one or more embodiments, the laser welder 102 is an automated laser welder. The laser welder 102 may include a disk laser manufactured by TRUMPF. The laser welder 102 may be configured to generate a single laser beam 120.

[0278] In various embodiments, the microstructure of the steel workpieces 106, 108 may be verified or studied in detail using an optical microscope or a scanning electron microscope (SEM). The optical microscope or the SEM may be operatively coupled to the controller. The output (e.g., the microstructure of the steel workpieces 106, 108) from the optical microscope or the SEM may be transmitted as data / information to the controller. The controller may be configured to process the data / information from the optical microscope or the SEM to determine the microstructure of the steel workpieces 106, 108 and / or control various other components of the system to adjust / change the microstructure of the steel workpieces 106, 108 as desired.

[0279] According to various non-limiting embodiments, the laser welder 102 is configured to generate a laser beam 120 having a laser beam diameter that is (a) at least 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, and / or 1.0 mm, (b) less than 2.0, 1.5, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, and / or 0.5, and / or (c) between any two such values (e.g., between 0.05 and 2.0 mm, between 0.3mm and 0.6mm).

[0280] According to various embodiments, the laser welder 102 may be configured to use a fiber laser to generate a laser beam 120 having a laser beam wavelength of (a) at least 600, 650, 700, 750, 800, 850, 900, 950, and / or 1000 nanometers, (b) less than 1500, 1400, 1300, 1200, 1100, and / or 1000 nanometers, and / or (c) between any two such values (e.g., 600-1500 nanometers, 800-1100 nanometers). According to one or more alternative embodiments, the laser welder 102 may be configured to use a CO2 laser (e.g., a Trumpf disk laser) to generate a laser beam 120 having a laser beam wavelength of (a) at least 300, 350, 400, and / or 450 nanometers, (b) less than 1000, 900, 800, 700, 650, 600, and / or 550 nanometers, and / or (c) between any two such values (e.g., 300-1000 nanometers, 300-500 nanometers). According to various embodiments, the wavelength affects the absorption of the laser energy by the weld pool, filler wire 116, and workpieces 106, 108, and may be tailored to provide an improved weld joint 114 (e.g., a weld joint 114 with a cross-sectional shape that is less hour-glass shapedand more rectangularly shaped resulting from improved melting in the middle of the workpieces 106, 108).

[0281] According to various embodiments, the laser welder 102 includes a laser with an output power of (a) at least 1, 2, 3, 4, 5, 6, 7, 8, 9, and / or 10 kw, (b) less than 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, and / or 6 kw, and / or (c) between any two such lower and upper values (e.g., 1-20 kw, 3-9 kw, 5-7 kw, ~ 6 kw, ~ 8 kw, etc.).

[0282] According to one or more embodiments the laser welder 102 provides a laser beam 120 that forms a generally round or oval spot with a highest beam intensity at the middle of the spot. However, according to various alternative embodiments, and as explained in greater detail below, the laser welder 102 additionally and / or alternatively provides a shaped beam 120 that forms a shaped spot at the beam-to-metal interface (e.g., where the beam impacts the surface(s) of the workpiece 106, workpiece 108, weld pool, and / or interface 112).

[0283] The area of the laser beam spot may be configured to (1) cover a localized area of the interface 112 between the steel workpieces 106, 108, (2) cover at least part of a localized area of the interface 112 between the steel workpieces 106, 108 and at least part of localized areas of each of the steel workpieces 106, 108, (3) cover at least part of a localized area of the interface 112 between the steel workpieces 106, 108 and at least part of a localized area of one of the steel workpieces 106, 108 (e.g., the steel workpiece 106, 108 having higher thickness), (4) cover a localized area of one of the steel workpieces 106, 108 (e.g., the steel workpiece 106, 108 having higher thickness), or (5) other localized areas. For example, the laser beam 120 may be centered with respect to the interface 112 between the steel workpieces 106, 108 in cases (1) and (2) above, while the laser beam may be laterally offset with respect to the interface 112 between the steel workpieces 106, 108 in cases (3) and (4) above. For example, case (1) may be used for applications having both thinner workpieces, case (2) may be used for applications having both thicker workpieces, while cases (3) and (4) may be used for applications with a combination of a thinner workpiece and a thicker workpiece.

[0284] The multiple laser beams 120 may have their own independent focal laser beam spot diameter / size and energy density during the laser welding procedure. The focal laser beam spot diameter may remain unchanged during the entire laser welding procedure. The energy density may remain the same or may change with the laser power, which may also vary. The controller may be configured to control the laser welder 102 to adjust / change the laser power over the course of the welding procedure. For example, power may ramp up at the beginning of theinterface 112 and ramp down at the end of the interface 112 to avoid burn through at the beginning or end of the weld joint 114.

[0285] The controller may be configured to control the laser welder 102 to adjust the laser spot spacing and / or distribute the intensity within a laser spot. With the spot-in-spot configuration, for example, symmetrical and asymmetrical weld seams may be achieved with a better weld quality than with conventional circular or rectangular spots, and at high speeds. The spot-in-spot technique may be used, among other things, for welding metal substrates with filler wire (e.g., the steel substrates 106, 108 with the filler wire 116).

[0286] The process parameters for laser welding may include laser power, weld speed, and focusing optics. All of these parameters may be interactive. That is, each of the process parameters of the laser welder 102 may be controlled by the controller. For a given focusing optic and workpiece / substrate material thickness, and assuming that full-penetration welds are desired, the higher the power, the faster the weld speed. The focal length of the optics may influence the beam spot diameter at focus. For a given laser beam, the focus spot diameter varies directly with focal length. For a short focal length optic, focus spot size is small and power density is high. This results in a narrow fusion zone at fast weld speed and low laser power for welding thin materials.

[0287] According to various embodiments, the welding speed in terms of length of joint / interface 112 welded per time is (a) at least 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and / or 15 meters / minute (e.g., at least 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 and / or 250 mm / s), (b) less than or equal to 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4.5, 4, 3.5, 3, 2.5, 2.0, and / or 1.5 meters / minute (e.g., less than or equal to 330, 300, 270, 250, 240, 230, 220, 210, 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 80, 70, 60, and / or 50 mm / s), and / or (c) between any two such values (e.g., 0.5-20 meters / minute, 1-10 meters per minute, 2.5-8.0 meters / minute, 3-6 meters / minute, about 6 meters / minute, 10-330 mm / s, 20-60 mm / s, 80-120 mm / s, about 100 mm / s). Many sheet metal applications with material thickness ranging from 0.03 to 0.08 inch (0.75 to 2 millimeters) may be welded at higher speeds, while thick-section welding applications may tend to require slower welding speeds. According to various embodiments, a higher power laser welder 102 can facilitate a higher welding speed.

[0288] In one or more embodiments, during the laser weld procedure, the laser welder 102 is configured to produce either a continuous high power density laser beam 120 or a pulsed high power density laser beam 120 to melt the materials of the workpieces 106, 108 beingjoined. The laser welder 102 may be configured to generate different laser beams 120 that exhibit the same or different output modes (the continuous output mode or pulsed output mode) at the same time. In one or more embodiments, as noted above, the spot size of the laser beam 120 may be varied by adjusting the focal point of the laser beam 120. In one or more embodiments, the laser welder 102 includes a focus lens 152 as shown in FIG. 9 that is configured to focus the laser beam 120 onto the desired spot on the workpieces 106, 108 or onto the weld interface 112 between the workpieces 106, 108.

[0289] In one or more embodiments, the laser welder 102 is configured to be dynamically adjustable to the workpieces 106, 108 into a variety of different interfaces 112 and resulting joint configurations, such as lap joints, butt joints, T-joints, bi-linear joints, multi-linear joints, corner joints or edge joints.

[0290] In one or more embodiments, the laser wattage, spot size, and / or beam shape of the laser welder 102 are chosen based on the material(s) being welded, the material thickness and the joint configuration.

[0291] According to various embodiments, one or more of characteristics of the laser welder 102 described herein (e.g., beam 120 shape, use of multiple beams, X / Y oscillation pattern) result in more homogeneous mixing of material within the weld joint 114, which may result in a stronger weld joint 114. According to various embodiments, homogeneity is beneficial throughout the weld joint 114. However, according to various embodiments, increased homogeneity is particularly beneficial at likely crack starting points, including (1) in the toe region of the weld joint 114, and / or (2) at the surface of the weld joint 114 where the weld joint 114 meets the base workpiece 106, 108.4. Multiple Laser Beams

[0292] According to various embodiments, the laser welder 102 utilizes single-beam laser energy to heat, melt, and weld the workpieces 106, 108 and filler wire 116. Alternatively, the laser welder 102 may be configured to generate multiple laser beams 120. In various embodiments, the laser welder 102 may be a single laser that is configured to generate a single laser beam 120. In another embodiment, the laser welder 102 may be a single laser that is configured to generate multiple laser beams 120. In yet another embodiment, the laser welder 102 may be multiple lasers that are configured to generate multiple laser beams 120. The number of laser beams 120 generated may vary depending on the application (e.g., thickness of the workpieces, the type of weld joint 114 configuration, whether filler wire 116 or poweradditive is being use, the type of the filler wire 116 or the powder additive etc.). According to various embodiments, the number of laser beams 120 generated may be 1, 2, 3, 4, 5, or more.

[0293] According to various embodiments, the laser welder 102 utilizes multiple laser beams 120 (e.g., one laser beam to heat the workpieces 106, 108 and / or filler wire 116 and another laser beam to melt and weld the components). The multiple laser beams 120 may result from separate laser generators or from a single laser generator with a beam splitter. According to various embodiments, one laser beam 120 may be used to melt the filler wire 116 while another laser beam 120 is used to melt one or both workpieces 106, 108.

[0294] The two or more laser beams 120 may result from splitting one beam into several individual laser spots. That is, the controller may be configured to control the laser welder 102 so as to split the laser beam 120 into several individual laser spots. Alternatively, the two or more laser beams 120 may originate from respective laser generators. The two or more laser beams 120 may include a first leading laser beam 120 that impinges on the welding location (e.g., workpiece(s) 106, 108, filler wire 116, interface 112) first and a second trailing laser beam 120 that impinges on the welding location second. According to various embodiments, the leading beam 120 may melt the filler wire 116 and / or workpieces 106, 108, and the trailing beam 120 may facilitate improved mixing within the weld pool to create a more homogeneous mixture of parent materials within the weld joint 114.

[0295] According to various embodiments, the leading beam 120 and trailing beam 120 may have different lateral (e.g., Y direction) offsets relative to the interface 112. For example, if the workpieces 106, 108 have different thicknesses, the leading beam 120 may be laterally offset toward the thicker of the workpieces 106, 108, as explained in greater detail below. The trailing beam 120 may be laterally centered over the interface 112 to improve mixing of material in the weld pool. The filler wire feed 104 may be laterally aligned with the lead beam 120 so that the lead beam 120 helps to melt the wire 116. Alternatively, the filler wire feed 104 may be laterally aligned with the trailing beam 120 so that the trailing beam 120 ensures appropriate melting of the filler wire 116 and mixing of the filler wire 116 material with the melted parent material from the workpieces 106, 108 in the weld pool.5. Hybrid Laser Welding

[0296] According to alternative embodiments, the laser welder 102 comprises a hybrid laser welder 102, which relies on both laser energy and other energy (e.g., arc welding) to weld the workpieces 106, 108 (e.g., hybrid laser arc welding).6. Optional Removal Of Coating(s) 118

[0297] According to various non-limiting embodiments, a portion of a coating 118 of one or both sides of one or both workpieces 106, 108 near the to-be-welded edges may be wholly or partially removed prior to welding (e.g., via ablation (e.g., chemical ablation, laser ablation), machining, or other removal process). According to various embodiments portions of the coating 118 on the top and / or bottom surfaces of the workpieces 106, 108 that are within a certain distance (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, and / or 10 mm) of the to-be-welded edge of the workpiece 106, 108 may be removed before the welding process.

[0298] In one or more embodiments, the laser welder 102 may be configured to partially ablate or otherwise remove (e.g., physical removal, e.g., via machining, chemical etching, etc.) the metal alloy layer of the coating(s) 118 on one or more sides of one or more of the steel workpieces 106, 108 prior to (e.g., immediately prior to) welding the workpieces 106, 108 together. The laser welder 102 may be configured to completely ablate or otherwise remove the metal alloy layer and / or the intermetallic alloy layers of the coating(s) 118 on one or more sides of one or more of the steel workpieces 106, 108.

[0299] In various embodiments, the aluminum based coating 118 is not removed from the workpieces 106, 108 near the weld joint 114 prior to welding the sheets. As explained herein, the use of particular filler wire 116 and / or a shaped laser beam 120 may account for the dispersion of coating aluminum into the weld joint 114 and limit any resulting weakening of the weld joint 114. However, according to one or more alternative embodiments, some or all of the aluminum based coating 118 can be removed from surfaces of the workpieces 106, 108 near where the weld joint 114 is to be formed prior to welding. For example, as shown in FIGS. 13-14, the aluminum-silicon layer 106a, 108a on the workpieces 106, 108 may be removed prior to welding, while leaving the intermetallic layer 106b, 108b on the workpieces 106, 108 intact. According to one or more embodiments, a shaped and / or varying-shaped laser beam 120 from the laser welder 102 (or a standalone ablation laser system that is separate from a welding laser) can be used to ablate the aluminum-silicon coating 106a, 108a from one or both surfaces of one or both workpieces 106, 108 prior to welding the workpieces 106, 108 together. In such an embodiments, as shown for example in FIG. 13 (before ablation) and FIG. 14 (after ablation), one laser ablation system 102 may be disposed above the workpieces 106, 108 to ablate the aluminum-silicon coating 106a, 108a on the top surfaces of the workpieces 106, 108 near the to-be-formed weld 114, and a second laser ablation system 102 may be disposed below the workpieces 106, 108 to ablate the aluminum-silicon coating 106a, 108a from the bottom surfaces of the workpieces 106, 108 near the to-be-formed weld. According to variousembodiments, the ablation removes at least 50, 60, 70, 80, 90, 95, and / or 100% of the aluminum-silicon coating 106a, 108a on one or both surfaces of one or both workpieces 106, 108. According to various embodiments, the intermetallic layer 106b, 108b remains intact after ablation. After ablation, the same laser system 102 or a different laser system 102 can be used to weld the ablated workpieces 106, 108 together.

[0300] According to one or more embodiments, the coating 118 on the top surface (i.e., the surface facing the laser welder 102 and laser beam 120) of one or both workpieces 106, 108 is partially or completely removed before welding, while the coating 118 on the bottom surface of the workpieces 106, 108 remains intact prior to welding. This reduces the amount of aluminum entering the weld joint 114 from the top surface(s) of the workpieces 106, 108. According to various embodiments, the coating 118 on the top surface(s) can be removed via laser ablation using the same laser 102 as is subsequently used for welding the workpieces 106, 108 together. According to various embodiments, removal of the coating 118 on the top surface(s) results in the weld joint 114 being wider at its top surface than at its bottom surface. As viewed in cross-section, the resulting weld joint 114 may have the shape of a top-heavy hour glass.

[0301] In various embodiments of the method 500, the coating 118 on one or more sides of one or more of the workpieces 106, 108 is not ablated or otherwise removed from areas around the interface 112 prior to the welding process. As a result, the welding process proceeds along an interface 112 in which the workpiece(s) 106, 108 have an aluminum based coating on one or both main surfaces where the workpiece(s) 106, 108 are melted by the welding process. In one or more embodiments, the method 500 does not require an ablation procedure (e.g., by an ablation laser) to remove the aluminum-silicon coating 118. In one or more embodiments, the method 500 does not require any uncoating procedure to remove the aluminum based coating 118. This creates a cheaper and faster manufacturing process or procedures. As explained herein, the lack of removal of the aluminum based coating before welding results in aluminum polluting the weld joint 114, which can weaken the weld joint 114. As explained herein, various techniques can be employed according to various non-limiting embodiments to mitigate the detrimental effects of such aluminum in the weld joint 114 (e.g., via use of nickel rich filler wire 116, via a welding process that ensures better homogeneous mixing of aluminum into the weld joint 114, etc.).

[0302] In one or more embodiments, the method of the present patent application provides shifts in a continuous cooling transformation (CCT) phase diagram to promote martensitic micro structure.7. Shielding Gas

[0303] In one or more embodiments, the laser welder 102 includes an inert shield (or protective) gas system. In one or more embodiments, the inert shield gas system is configured to supply or provide an inert shield gas onto the workpieces 106, 108. In one or more embodiments, the inert shield gas is directed onto portions of the surfaces of the workpieces 106, 108 during the laser weld procedure. In one or more embodiments, the inert shield gas may be an inert gas (e.g., nitrogen, carbon dioxide, argon, helium, or any combination thereof) that is configured to shield the molten weld pool. In one or more embodiments, the inert shield gas system of the laser welder 102 includes a gas flow sensor that is configured to sense / detect the flow rate of the inert shield gases used in the laser weld procedure. In one or more embodiments, the gas flow sensor is configured to provide a signal proportional to the gas flow rate in the inert shield gas line. In one or more embodiments, the one or more processors of the laser welder 102 are configured to stop welding if the gas flow rate of the inert shield gas is not within a predetermined gas flow rate range. In one or more embodiments, the inert shield gas system is optional.

[0304] According to one or more alternative embodiments, air is used instead of an inert gas for the shielding gas system. The air or inert gas tends to blow smoke away from the welding location, which advantageously increases the amount of laser beam 120 energy that reaches the workpieces 106, 108 and / or filler wire 116.8. Filler Wire Feed

[0305] In one or more embodiments, the filler wire feed 104 is a filler wire feed shown in FIGS. 3-5. In one or more embodiments, the filler wire feed 104 includes one or more wire feed cables / tubings 202, a filler wire feed box 204, a filler wire spool 206, a wire feeder 208, and a wire feed nozzle 210.

[0306] In one or more embodiments, the method 500 also comprises: forming (e.g., procedure 504 as shown in FIG. 2) the weld joint 114, by the laser welder 102, between the workpieces 106, 108 along the interface 112; and feeding (e.g., procedure 506 as shown in FIGS. 1 and 2) the filler wire 116, by the filler wire feed 104, to the interface 112 when the workpiece 106 and the at least one additional workpiece 108 are being welded to each other to form the welded assembly 110.

[0307] FIGS. 1 and 2 show two orthogonal views of the same wire feed 104 arrangement. As shown in FIG. 2, the filler wire feed 104 (i.e., supplying the filler wire 116) is positioned ahead (i.e., in the direction of the welding Dw) of the laser welder 102. In one or more embodiments, as shown in FIG. 1, the filler wire feed 104 (i.e., supplying the filler wire 116) is positioned on the same longitudinal X / Z plane as the laser welder 102. This longitudinal X / Z plane extends perpendicularly into and out of the view shown in FIG. 1, and extends from left to right across the view in FIG. 2. In one or more embodiments, as shown in FIG. 2, the filler wire feed 104 (i.e., supplying the filler wire 116) is positioned at an angle with respect to the workpieces 106, 108. FIGS. 1 and 2 show different views of the same process. In one or more embodiments, the filler wire 116 is fed at an angle.

[0308] FIG. 6 shows a procedure of the method 500 in which a weld start position in shown, while FIG. 7 shows a procedure of the method 500 in which a weld end position is shown. Both the laser welder 102 (projecting the laser beam 120) and the filler wire feed 104 (providing the filler wire 116) are moved over a weld path between the weld start position of FIG. 6 and the weld end position of FIG. 7 along the interface 112. According to one or more embodiments, the filler wire feed 104 is mounted to a laser head of the laser welder 102 so that the filler wire feed 104 and laser head move together relative to the workpieces 106, 108 being welded.

[0309] In one or more embodiments, as discussed above, the filler wire 116 comprises nickel and chromium. In one or more embodiments, the method 500 further comprises binding the filler wire 116 with aluminum in the aluminum based coating 118, when the workpieces 106, 108 are being welded to each other to form the welded assembly, so as to minimize the formation of brittle intermetallics in the weld joint 114 due to the mixing of the aluminum in the aluminum based coating 118 with the iron / steel material of the workpieces 106, 108 within the weld joint 114.

[0310] In one or more embodiments, aluminum reaction with iron is minimized. In one or more embodiments, the aluminum-iron intermetallic is the main brittle intermetallic being formed. In one or more embodiments, the filler wire 116 is configured to prevent or reduce the formation of this aluminum-iron intermetallic. In one or more embodiments, the nickel in the filler wire 116 is configured to bind with the aluminum.

[0311] In one or more embodiments, the filler wire 116 is also tracked using an encoder, which makes quality assurance and tracking much more efficient and certain.9. Filler Wire Feed Rate And Weld Joint Shape

[0312] According to various embodiments, the feed rate of the filler wire 116 when performing the laser welding procedure is (a) at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110 and / or 120 mm / s, (b) less than or equal to 250, 200, 190, 180, 170, 160, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, and / or 10 mm / s, and / or (c) between any two such values (e.g., 5-250 mm / s, 50-90 mm / s, 60-80 mm / s, 20-60 mm / s, about 70 mm / s, about 80 mm / s, about 50 mm / s, about 60 mm / s).

[0313] According to one or more embodiments, the filler wire 116 feed rate may be adjusted relative to the welding speed (e.g., slower filler wire feed rate for slower welding speed).

[0314] According to one or more embodiments, the filler wire feed rate is selected based on a diameter or cross-sectional area of the wire 116 so as to provide an appropriate volumetric or mass feed rate for the wire 116 relative to the welding speed along the interface 112. According to various embodiments, a higher feed rate is used for thinner wire 116 than would be used for a wire 116 with a larger cross-sectional area. For example, if the feed rate is 70 mm / s and the circular cross-section filler wire has a 0.9 mm diameter, the volumetric feed rate is: 70 mm / s x it (0.9mm / 2)2, i.e., about 45 mm3 / s. According to various embodiments, the volumetric feed rate of the filler wire 116 when performing the laser welding procedure is (a) at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100, 110, 120, 130, 140, and / or 150 mm7s, (b) less than or equal to 200, 190, 180, 170, 160, 150, 140, 130, 120, 110, 100, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, and / or 20 mm3 / s, and / or (c) between any such values (e.g., 15-200 mm3 / s, 30-70 mm3 / s).

[0315] According to one or more embodiments, the filler wire feed rate is based on a thickness of the workpieces 106, 108.

[0316] According to one or more embodiments, the filler wire feed rate is based on the composition of the workpieces 106, 108. For example, a higher feed rate may be used when welding two high strength workpieces 106, 108, than when welding a high strength workpiece to a low strength workpiece. A higher feed rate may be used when welding two high strength Al-coated workpieces 106, 108 in order to provide more filler wire material in the weld joint 114 and better account for the presence of aluminum in the weld joint 114, which may help to ensure that the weld joint 114 is as strong or stronger than a weaker of the workpieces 106, 108.

[0317] According to various embodiments, the filler wire feed rate is selected relative to the welding speed and interface 112 gap size such that sufficient volume of filler wire 116 material is fed into the melt pool forming the weld joint 114 to create a desired cross-sectional profilefor the joint 114. For example, if the interface 112 gap width is 0.1 mm, both workpieces 106, 108 are 1.2 mm thick, and the welding speed is 5 meters / minute (i.e., 83 mm / s), the volume of the gap volume as a function of welding speed (hereinafter “welding gap rate”) is 0.1 mm x 1.2 mm x 83 mm / s, i.e., 10 mm3 / s.

[0318] If the workpieces 106, 108 have different thicknesses, the welding gap rate is calculated using the thickness of the thinner of the workpieces 106, 108. For example, if the first workpiece 106 is 1.2 mm thick, the second workpiece is 2.0 mm thick, the gap is 0.1 mm wide, and the welding speed is 100 mm / s, the welding gap rate is 1.2 mm x 0.1 mm x 100 mm / s, i.e., 12 mm3 / s.

[0319] According to various embodiments, the cross-sectional profile of the weld joint 114 is preferably slightly convex such that the weld joint 114 is slightly thicker than a thickness of the thinner workpiece 106, 108. According to various embodiments, the filler wire feed rate is selected to avoid an overly convex weld joint, as would result from excessive filler wire being present in the weld joint 114. According to various embodiments, the filler wire feed rate is selected to avoid a concave profile in which the weld joint 114 is thinner than the thinner workpiece 106, 108.

[0320] As shown in FIGS. 18-19, the weld joint 114 has a minimum thickness DMIN defined as the minimum dimension from the weld root (bottom surface) to the weld face (top surface where the laser beam 120 meets the workpieces 106, 108), measured perpendicular to the main faces of the workpieces 106, 108. Similarly, the weld joint 114 has a maximum thickness DMAX defined as the maximum dimension from the weld root (bottom surface) to the weld face (top surface), measured perpendicular to the main faces of the workpieces 106, 108. The thicker of the workpieces 106, 108 has a thickness T. The thinner of the workpieces 106, 108 has a thickness t. According to various embodiments, if t is less than 1.0 mm, then DMIN is preferably at least 0.85t, and DMAX is preferably less than or equal to T+0.15t. According to various embodiments, if t is at least 1.0 mm and the workpieces 106, 108 have different thicknesses, then DMIN is preferably at least 0.80t, and DMAX is preferably less than or equal to: T+0.30t, and / or T+0.20t.

[0321] According to various embodiments, and as shown in FIGS. 18-19, the cross-sectional profile of the weld joint 114 (as taken in the Y / Z plane perpendicular to the weld joint 114) is preferably slightly overfilled on the top and bottom of the weld joint 114. Overfill OTOP of the top of the weld joint 114 is a measure of the extent to which the weld joint 114 extends upwardly past (e.g., proud of) a plane defined by the adjacent top surface of the workpiece 106,108 whose adjacent surface is most elevated (e.g., the workpiece 106 shown in FIGS. 17-19). If the workpieces 106, 108 have the same thickness and are not vertically offset from one another (e.g., as shown in FIG. 1), then the overfill OTOP at the top of the weld joint 114 is measured by the vertical extent to which the highest point of the weld joint 114 extends upwardly past the co-planar top surfaces of the workpieces 106, 108. If the workpieces 106, 108 have different thicknesses or are vertically misaligned, then the top surface overfill OTOP is measured relative to the top surface of the workpiece 106, 108 that is highest (e.g., the top surface of the workpiece 106 as shown in FIGS. 17-19). Overfill OBOTTOM at the bottom of the weld joint 114 is measured in the same way, but in the opposite / downward direction.

[0322] According to various embodiments, a top surface overfill OTOP and / or the bottom surface overfill OBOTTOM at at least one cross-section perpendicular to the weld joint 114, taken at a location along the length of the weld joint 114, is (a) at least 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and / or 13% of a thickness t of the thinner of the workpieces 106, 108 (e.g., the workpiece 108 shown in FIGS. 17-19), (b) not more than 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, and / or 6 % of a thickness t of the thinner workpiece 106, 108, and / or (c) between any two such values (e.g., from 1-20%, 1-10%, 10-15%, 10-25%, or 5-15% of the thickness t of the thinner workpiece 106, 108). According to various embodiments the total overfill (OTOP + OBOTTOM) at at least cross-section perpendicular to the weld joint 114, taken at a location along the length of the weld joint 114, is (a) at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 27, 28, 29, and / or 30% of the thickness t of the thinner workpiece 106, 108, (b) not more than 35, 30, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, and / or 6 % of the thickness t of the thinner workpiece 106, 108, and / or (c) between any two such values (e.g., 1-35%, 1-20%, 1-15%, 10-25%, 15-35%, 20- 35%, or 7-15% of the thickness t of the thinner workpiece 106, 108).

[0323] According to various embodiments, Applicant discovered that a large overfill resulted in a strong joint and that such a benefit outweighed the potential downsides (e.g., having to stamp a welded blank 110 with a protruding weld joint 114). In particular, according to various embodiments it was found that a top overfill OTOP of at least 10% and / or 15% of the thickness t provided a strong j oint, despite being larger than preferred by one or more customers. According to various embodiments it was found that a bottom overfill OBOTTOM of at least 10% and / or 15% of the thickness t provided a strong joint, despite being larger than preferred by one or more customers. According to various embodiments it was found that a total overfill (OTOP + OBOTTOM) of at least 15 and / or 20% of the thickness t provided a strong joint, despitebeing larger than preferred by one or more customers. In contrast, one or more customers have conventionally required a maximum overfill of less than 10% of thickness t at the top and bottom surface at every cross-section along the entire joint 114, and a total overfill of less than 20 and / or 15% of thickness t at every cross-section along the entire joint 114.

[0324] According to various embodiments, the top surface overfill OTOP tends to be larger than the bottom surface overfill OBOTTOM.

[0325] According to various embodiments, a greater degree of overfill is preferable when both workpieces 106, 108 are high strength steels (e.g., Usibor 1500) than when one workpiece 106, 108 is a high strength steel (e.g., Usibor 1500) and the other workpiece 106, 108 is a low strength steel (e.g., Ductibor 500). According to various embodiments, the greater overfill used for high-strength-to-high-strength workpieces 106, 108 makes it more likely for welded assembly 110 to fail in a base workpiece 106, 108 than in the weld joint 114, which demonstrates the strength of the weld joint 114. According to some embodiments, overfill is less important for high-strength-to-low-strength weld joints 114 because welded blank tends to fail in the low strength workpiece 106, 108 regardless of the extent of overfill of filler wire 116 in the weld joint 114, so the weld joint 114 is not the weak point.

[0326] As shown in FIGS. 18-19, a top surface underfill UTOP of the weld joint 114 is a measure of the extent to which any portion of the weld joint 114 does not extend past the lower of the top surfaces of the workpieces 106, 108 (e.g., the workpiece 108 shown in FIGS. 17-19). The weld joint 114 shown in FIG. 18 has a slight top surface underfill UTOP. The weld joint 114 shown in FIG. 19 has no top surface underfill UTOP. A bottom surface underfill UBOTTOM of the weld joint 114 is measured in the same way, but in the opposite / downward direction. The weld joint 114 shown in FIG. 18 has a slight bottom surface underfill UBOTTOM. The weld joint 114 shown in FIG. 19 has no bottom surface underfill UBOTTOM. According to various embodiments, top and bottom surface underfill is preferably avoided. In this regard, the weld joint 114 shown in FIG. 19 is preferable to the weld joint 114 shown in FIG. 18.

[0327] According to various embodiments, UTOP is not more than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1% of the thickness t of the thinner workpiece 106, 108. According to various embodiments, UBOTTOM is not more than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1% of the thickness t of the thinner workpiece 106, 108. According to various embodiments, the total top and bottom underfill (UTOP + UBOTTOM) at any cross section of the weld joint 114 is not more than 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1 % of the thickness t of the thinner workpiece 106, 108. Accordingto various embodiments, UTOP is less than 10% of thickness t, UBOTTOM is less than 10% of thickness t, and total underfill (UTOP + UBOTTOM) is less than 15% of thickness t.

[0328] According to various embodiments, a volumetric feed rate of the filler wire 116 exceeds the welding gap rate, which may result in a convex and / or overfilled weld joint 114 because more filler wire 116 material is added than is needed to fill the gap in at the interface 112. According to various embodiments, a volumetric feed rate of the filler wire 116 exceeds the welding gap rate by (a) at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and / or 20% of the welding gap rate, (b) less than or equal to 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, and / or 2% of the welding gap rate, and / or by any value between such limits (e.g., by at least 1-25% of the welding gap rate, by at least 1-10% of the welding gap rate). According to various embodiments, a volumetric feed rate of the filler wire 116 exceeds the welding gap rate by (a) at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, and / or 50 mm3 / s, (b) less than or equal to 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, and / or 2 mm3 / s, and / or (c) by any value between such limits (e.g., by at least 1 to 75 mm3 / s, by at least 10-40 mm3 / s). However, according to various alternative embodiments, the filler wire 116 feed rate is selected to be smaller than the welding gap rate, which may result in a slightly concave weld profile. According to various embodiments, when assessing an appropriate filler wire 116 feed rate relative to the welding gap rate, the filler wire feed rate is selected to account for lost material (e.g., filler wire 116 and / or workpiece 106, 108 material that splatters away from or bums off of the weld joint 114).

[0329] According to various embodiments, the filler wire feed rate is selected relative to the welding speed to feed a predetermined volume of filler wire 116 per length of interface 112. The resulting filler wire feed rate is independent of time. According to various embodiments, a volumetric feed rate of the filler wire 116 is V mm3per linear mm along the interface 112(i . e., the X direction shown in FIG. 2). According to various embodiments, V is (a) at least 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and / or 0.9, (b) no more than 4, 3, 2, 1, 0.9, 0.8, and / or 0.7, and / or (c) between any two such values (e.g., 0.2-4). According to various embodiments, when an average interface gap is about 0.1 mm and the workpieces 106, 108 have the same thickness, V is preferably at least 0.3, 0.4, and / or 0.5.

[0330] Unless otherwise specifically stated, weld joint 114 physical characteristics such as convexity, overfill, underfill, and thickness are measured before stamping.10. Variable Filler Wire Feed Rate

[0331] In one or more embodiments, the filler wire feed speed is varied using adaptive welding to vary the weld speed according to gaps or other miscellaneous features at the interface 112. According to one or more embodiments, the filler wire 116 feed rate (in terms of linear and / or volumetric rate) varies along the length of the interface 112 based on detected changes in the width of the gap at the interface 112. For example, a seam camera 600 or other sensor may sense the localized gap width of the interface 112 along the length of the interface 112, either before the laser welding operation or during the laser welding operation. During the welding operation, a controller for the filler wire feed 104 may responsively increase the filler wire 116 feed rate where the gap widens and decrease the filler wire 116 feed rate where the gap narrows. According to various embodiments, the controller may vary the instantaneous filler wire 116 feed rate responsive to instantaneous changes in the welding gap rate where the welding is occurring.11. Filler Wire Preheating

[0332] According to various embodiments, the filler wire feed 104 (or a separate part of the system) includes a preheater, which preheats the filler wire 116 before the filler wire 116 is used to weld the workpieces 106, 108 together. According to various embodiments, the preheater comprises any structure usable to heat the filler wire 116 to a temperature below the wire’s melting temperature, e.g., a electrical resistance heater, an electric inductive heater, a radiant heater, laser (either separate from the welding laser or a beam split off from the welding laser).

[0333] According to various embodiments, the preheated filler wire 116 is then melted by the laser beam 120’s direct energy (impingement of the laser beam 120 on the filler wire 116) or indirect energy (insertion of the filler wire 116 into a weld melt pool, which melts the filler wire 116). For example, the filler wire 116 may be heated by the preheater before the filler wire 116 is fed to the weld melt and / or welding laser beam 120.

[0334] In other embodiments, the filler wire 116 is not preheated before the laser welding procedure, and instead is both heated and melted by direct and / or indirect energy from the laser beam 120. The filler wire 116 may intersect with the laser beam 120 above the gap / interface 112. According to various embodiments, the filler wire 116 intersects the laser beam 120 before touching the steel workpieces 106, 108 or melt pool, and the filler wire 116 remains 0.1mm or 0.2mm above the surfaces of the steel workpieces 106, 108 until melting and dropping into the interface 112 and / or melt pool and mixing with the parent material from the steel workpieces 106, 108. According to alternative embodiments, the filler wire 116 intersects and contacts themelt pool before interesting the laser beam 120, which may result in the heat within the melt pool melting the filler wire 116.12. Alignment Of Filler Wire And Laser Beam Relative To Interface

[0335] The beam axis (e.g., centrally disposed) of the laser beam 120 extends along the Z axis substantially perpendicular to surfaces of the first and second steel workpieces 106, 108, which are in the X / Y plane.

[0336] The laser welder 102’s controller, which includes one or more processors, may be operatively connected to the laser welder 102 and may be configured to control a lateral offset of the laser beam 120 in a lateral (Y) direction relative to the interface 112.

[0337] According to various embodiments, the laser beam 120 and filler wire feed 104 are generally aimed at the middle of the gap / interface 112 between the two steel workpieces 106, 108 when the two steel workpieces 106, 108 have the same thickness (e.g., 1mm each or 2mm each or 1.5mm each). For example, when the two steel workpieces 106, 108 have the same thickness of 1 mm each, 1.5 mm or 2 mm each, the laser beam 120 is generally aimed at the middle of the gap / interface 112 between the two steel workpieces 106, 108. That is, there is no lateral offset of the laser beam 120 and the filler wire 116 (with respective to the interface 112) when the two steel workpieces 106, 108 have the same thickness.

[0338] It was discovered that in one or more embodiments, when the laser welding process is applied to workpieces 106, 108 with dissimilar thicknesses and the laser beam 120 is centered in the interface 112, elements from the filler wire 116 did not homogeneously disperse within the resulting weld joint 114. The lack of homogeneous distribution of nickel in particular resulted in less binding of the nickel with aluminum in the weld joint 114, which resulted in a weaker weld joint 114.

[0339] As shown in the SEM scan in FIG. 20, in one example, a 1.2 mm thick high strength workpiece 106 (Usibor 1500) was welded to a 2.0 mm thick high strength workpiece 108 (Usibor 1500) using a 316L filler wire 116 and a welding laser beam 120 that was laterally centered over the interface 112 (no lateral offset). Using EDX, a nickel concentration within a box 740 toward an upper portion of the weld joint 114 was determined to be 4.8%, while a nickel concentration within a box 750 toward a bottom of the weld joint 114 was determined to be 0.52%. Insufficient mixing within the melt pool during welding resulted in relatively higher concentrations of nickel toward the top of the weld joint 114, where the nickel rich filler wire 116 was fed into the melt pool forming the weld joint 114. The resulting welded assembly110 had a UTS of 1006 MPa, and broke within the weld joint 114, showing that the uneven mixing of nickel within the joint 114 resulted in a weak joint.

[0340] As shown in FIG. 21, the welding process of FIG. 20 was repeated but with a 0.1 mm lateral offset of the laser beam 120 relative to a center of the interface 116 toward the thicker workpiece 108. This lateral offset resulted in the nickel within the joint 114 being more evenly distributed. A nickel concentration within an upper box 770 was determined to be 3.16%, while a nickel concentration within a lower box 780 was determined to be 2.62%. The resulting welded assembly 110 had a UTS of 1403 MPa, and broke within one of the workpieces 106, 108, showing that the more homogenous mixing of nickel within the joint 114 resulted in a stronger joint 114. It is believed that the lateral offset of the laser beam 120 resulted in better mixing of the filler wire 116 within the weld joint 114, which resulted in improved bonding between the nickel and aluminum and a stronger joint 114.

[0341] FIG. 17 illustrates an example of the use of a laterally offset laser beam 120 with workpieces 106, 108 having dissimilar thicknesses. As shown in FIG. 17, according to one or more alternative embodiments, the filler wire 116 feed 104 and the laser beam 120 are both offset in the lateral (i.e., Y) direction relative to the center of the interface 112 by a distance Y’ when the two steel workpieces 106, 108 have different thicknesses or comprise different materials.

[0342] The laser beam 120 and filler wire feed 104 may be offset in the lateral / Y direction relative to the interface 112 and towards the thicker steel workpiece 106, 108, as shown in FIG. 17. The laser beam 120 and filler wire feed 104 may be maintained in the offset configuration substantially along the entire longitudinal (e.g., X direction) length of the interface 112.

[0343] According to various embodiments, the laser beam 120 and filler wire feed 104 do not reciprocate / oscillate in a lateral / Y direction as the laser beam 120 progresses along the interface 112 to form the weld joint 114. However, according to alternative embodiments, the laser beam 120 and filler wire feed 104 may oscillate laterally while maintaining an average offset (e.g., oscillating to either side of the offset location during the welding procedure), as explained in greater detail below. If there is no Y direction oscillation, the average Y’ offset is the same as the Y’ offset. As used herein, the “average Y’” means a time-based average over the course of the laser welding procedure.

[0344] The desired aim of the laser beam 120 may depend on relative thickness of the two steel workpieces 106, 108. For example, if the thickness of one of the two steel workpieces 106, 108 is 1.0mm and the thickness of the other of the two steel workpieces 106, 108 is 2.0mm,the controller may be configured to offset the laser beam 120 in a lateral direction relative to the interface 112 and towards thicker of the first and second steel workpieces 106, 108 (e.g., the steel workpiece having a thickness of 2.0mm). The offset Y’ in this case may be 0.3mm.

[0345] According to one or more embodiments, if the laser beam 120 is 0.6mm in width / diameter and the laser offset of 0.3 mm, the center point / axis of the laser beam 120 is on the thicker of the two steel workpieces 106, 108. In other words, at least half of the size / diameter of the laser beam 120 is on the thicker of the two steel workpieces 106, 108.

[0346] According to one or more embodiments, if the laser beam 120 is 0.3mm in width / diameter and with the Y’ laser offset of 0.3mm, the entire laser beam 120 is on the thicker of the two steel workpieces 106, 108. In other words, the size / diameter of the laser beam 120 is on the thicker of the two steel workpieces 106, 108. In this case, melting of the thicker workpiece in turn melts the thinner workpiece 106, 108.

[0347] According to one or more embodiments, if the thickness of one of the two steel workpieces 106, 108 is 1.5 mm and the thickness of the other of the two steel workpieces 106, 108 is 2.0 mm, the controller may be configured to offset the laser beam 120 in a lateral direction relative to the interface 112 and towards the thicker of the first and second steel workpieces 106, 108 (e.g., the steel workpiece having a thickness of 2.0mm). The Y’ offset in this case is 0.1mm.

[0348] According to various embodiments, the Y’ lateral offset of the laser beam 120 and filler wire feed 104 is (a) at least 0.05, 0.1, 0.2, and / or 0.3 mm, (b) less than or equal to 0.5, 0.4, 0.3, 0.2, and / or 0.1 mm, and / or (c) between any two such values (e.g., 0.05-0.5 mm, 0.1- 0.3 mm). According to various embodiments, the Y’ offset amount is selected so as to be proportional to (a) the absolute thickness difference between the workpieces 106, 108 (e.g., a larger offset for a 1.0 mm thickness difference than for a 0.5 mm thickness difference), and / or (b) the relative thicknesses of the workpieces 106, 108 (e.g., a larger offset for 50% thickness difference than for a 25% thickness difference).

[0349] According to various embodiments, the laser beam 120 may also be laterally offset from the interface 112 when used to weld workpieces 106, 108 that have the same thickness, but comprise different materials. For example, the laser beam 120 may be offset by Y’ toward the workpiece 106, 108 having a higher melting temperature in order to better ensure appropriate melting of both workpieces 106, 108 during the welding process.

[0350] Additionally and / or alternatively, the laser beam 120 may be laterally offset by Y’ from the interface 112 toward the higher strength workpiece 106, 108 such that relatively moreof the high strength workpiece 106, 108 parent material forms the weld joint 114. According to various embodiments, this may strengthen the resulting weld joint 114.

[0351] According to various embodiments, if one workpiece 106, 108 has an aluminum based coating 118 on its top surface near the interface 112, but the other workpiece’s top surface is uncoated near the interface 112, the laser beam 120 may be laterally offset by Y’ from the interface 112 toward the workpiece 106, 108 without the aluminum coating 118 on its top surface, which may reduce an amount of aluminum coating material entering the weld joint 114. Conversely, the laser beam 120 may be laterally offset by Y’ from the interface 112 toward the workpiece 106, 108 with the aluminum coating 118 on its top surface, which may improve the beam’s ability to melt the coated workpiece 106, 108 through the coating 118.

[0352] According to various embodiments, the filler wire feed 104 is offset from the interface 112 to the same Y’ extent as the laser beam 120, which helps to ensure that the laser beam 120 appropriately melts the filler wire 116 into the melt pool. However, according to one or more alternative embodiments, the filler wire 116 may remain centered in the interface 112 even when the laser beam 120 is laterally offset, so as to introduce the filler wire 116 material more directly into the gap / interface 112 between the workpieces 106, 108 during the laser welding process.

[0353] According to various alternative embodiments, a Y’ offset of the laser beam 120 may be larger than the Y’ offset of the filler wire 116 is (e.g., an offset of 0.2 mm for the laser beam 120, but an offset of 0.1 or 0 mm for the filler wire 116). According to various embodiments, the offset of the laser beam 120 is intended to melt an equal volume of each workpiece 106, 108 so that the workpieces 106, 108 contribute equally to the composition of the weld joint 114. According to various embodiments, if one workpiece 106, 108 comprises a higher strength material, the offset is selected to melt slightly more of the higher strength material so that the weld joint 114 comprises slightly more of the higher strength parent workpiece 106, 108 material than the relatively lower strength parent workpiece 106, 108 material.

[0354] According to various embodiments, the offset is intended to achieve 100% melt depth in each workpiece 106, 108, such that the weld joint 114 spans the full depth of each workpiece 106, 108. By offsetting the laser beam 120 toward the thicker (or higher melting temperature) workpiece 106, 108, the process compensates for the higher amount of energy needed to melt the workpiece 106, 108 to the full depth of the thicker or higher melting temperature work piece 106, 108, while also not overly melting the thinner (or lower melting temperature) workpiece 106, 108.

[0355] According to various embodiments, instead of and / or in addition to offsetting the laser beam 120, the size (e.g., diameter) of the laser beam 120 may be enlarged to help account for differences in thickness (or melting temperature) between the work pieces 106, 108.13. Seam Tracking

[0356] In one or more embodiments, the system 100 includes an optical seam tracker 600, as shown in FIGS. 8 and 9. In one or more embodiments, the optical seam tracker 600 is configured to project a laser beam 602 to illuminate the seam / interface 112. In one or more embodiments, the optical seam tracker 600 may include an optical seam camera 600a. In one or more embodiments, the camera 600a is configured to see and precisely locate the seam / interface 112. In one or more embodiments, as shown in FIG. 9, the camera 600a inspects, measures, and evaluates the seam / interface 112 prior to welding. According to various embodiments, the camera 600a may measure the location of the interface 112 (e.g., relative to the welder 102) and / or a width of a gap between the workpieces 106, 108 at the interface 112.

[0357] As shown in FIG. 9, the tracker 600 may include a weld inspection camera 600b, which inspects the weld joint 114 after welding.

[0358] In one or more embodiments, the seam tracker 600 includes both a seam tracker 600a for tracking a seam / interface 112 before welding and a weld inspection camera 600b for inspecting the weld joint 114 after welding. According to various embodiments, the tracker 600 is mounted to the head of the welder 102 such that the cameras 600a and / or 600b move with the head of the welder 102. According to various embodiments, the camera 600a views a portion of the interface 112 in front of where the laser beam 120 is aimed, and the camera 600b views a portion of the interface 112 behind the weld process to inspect, evaluate, and measure the weld seam / interface 112 before welding, and the weld bead / joint 114 after welding.

[0359] As shown in FIG. 9, both the optical seam tracker 600 and the filler wire feed 104 (i.e., supplying the filler wire 116) are positioned ahead (i.e., in the direction of the welding Dw) of the laser welder 102. In another embodiment, the optical seam tracker 600 is positioned ahead (i.e., in the direction of the welding Dw) of the laser welder 102 and the filler wire feed 104 (i.e., supplying the filler wire 116) is positioned on the same longitudinal axis as the laser welder 102 (e.g., similar to the arrangement of the laser welder 102 and the filler wire feed 104 in FIG. 1).14. Interface 112 Detection

[0360] According to one or more embodiments, prior to performing the laser welding operation, a camera such as the seam tracking camera 600a (e.g., mounted on the laser welder102) is used to precisely locate the intended start and end points of the to-be-formed weld 114 along the interface 112. The laser welder 102 can then perform a laser welding procedure following a straight line between those located start and end points. According to various embodiments, the camera 600a identifies the interface 112 and its end points by detecting light that passes through the interface 112 or that is reflected back to the camera 600.

[0361] However, in instances in which the gap at the interface 112 is small, the camera 600a may not be able to detect the interface 112 or its end points. According to various embodiments, portion(s) of the workpiece(s) 106, 108 at or near the edge to be welded may be shaped to make it easier for the camera to detect the ends of the interface 112.

[0362] According to various embodiments, as shown in FIG. 15, the mating edge of one workpiece 106, 108 is shifted laterally relative to the other workpiece 106, 108, which results in an inside corner 700 with a vertex 705 formed at each end of the interface 112. In FIG. 15, the entire workpiece 106 is laterally shifted relative to the other workpiece 108. However, this shift can alternatively result from the inclusion of a small gusset-shaped protrusion at the end of the mating edge of one or both workpieces 106, 108, which may result in less excess / wasted material.

[0363] According to an alternative embodiment, a notch / chamfer 710 is formed at one or both ends of one or both to-be-welded edges of one or both workpieces 106, 108 such that when the workpieces 106, 108 are positioned to form the interface 112, the notch(es) 710 form a V-shaped opening with the vertexes 720 of the V-shaped openings located at the start and end, respectively, of the intended weld joint 114 along the interface 112. According to various embodiments, the notch 710 extends 2.75 mm along the edge forming the interface 112 and is 0.3 mm deep (e.g., forming a triangular notch with a 0.3 mm side and a 2.75 mm side).

[0364] The vertex 705, 720 of the comer 700 (shown in FIG. 15) or V formed by the notch(es) 710 (shown in FIG. 16) is precisely detectable by the camera 600, which can ensure that the laser welder 102 can make a weld joint 114 that accurately follows the linear interface 112 between the two vertexes 705, 720. The portion of the workpieces 106, 108 that stick out past each vertex 705, 720 is preferably excess material that can be subsequently trimmed (e.g., via laser cutting) when the final edges of the product are later formed (e.g., before or after hot stamping).15. Laser Beam Oscillation

[0365] The laser welder 102 may be configured to generate a laser beam 120 having only linear movement (i.e., without oscillation) along the interface 112 (e.g., in the X direction).That is, the position of the laser beam 120 may remain along the linear path and may remain unchanged from that linear path. The linear path may be along the linear (e.g., a straight line or a curved line) interface 112 between the workpieces 106, 108 and may be along the weld joint 114 formed. The laser welder 102 may be configured to generate a laser beam 120 with at least some oscillation in a direction transverse to the direction of the weld joint 114 or interface 112 between the workpieces 106, 108. That is, the position of the laser beam 120 may be moved (arbitrarily) or the laser beam 120 may be oscillated to be within a predetermined distance from the linear path at the center of the interface 112 so as to generate a larger sized or shaped laser weld spot. The controller, including one or more processors, may be configured to control the laser welder 102 so as to control the movement of the laser beam 120, e.g., via an actuator that physically moves the laser generator(s) and / or an optical system that moves the beam 120 without moving the laser generator(s).

[0366] According to various embodiments, the laser beam 120 reciprocates in a direction (Y axis) transverse / lateral to the direction of the weld joint 114 / interface 112 as the laser beam 120 progresses along the weld joint 114 / interface 112 (X axis). According to alternative embodiments, the laser beam 120 does not reciprocate in a direction transverse to the direction of the weld joint 114 / interface 112 as the laser beam 120 progresses along the weld joint 114 / interface 112.

[0367] According to various embodiments, a motion path of the laser beam 120 is controlled in both the X axis direction of welding Dw (e.g., along the interface 112), as shown in FIG. 1, and in a lateral / transverse Y axis direction (e.g., perpendicular to the direction of welding and generally parallel to the top surfaces of the workpieces 106, 108), as shown in FIG. 1. According to various embodiments, the welder 102 may include a mechanized lens 152 (or equivalent mirror or mechanical drive) for controlling the X / Y location where the beam 120 impinges the workpieces 106, 108 and interface 112. This X / Y directional control, when combined with the absolute X direction movement of the welder 102 along the interface 112 (e.g., by moving the welder 102 and / or the work pieces 106, 108 relative to each other), facilitates a wide variety of laser 120 beam impingement patterns. For example, if the welder 102 is programmed to cause the beam 120 to oscillate purely in the Y direction while the laser welder 102 progresses in the X direction along the interface 112, the resulting laser pattern on the workpieces 106, 108 may have a zig-zag or sinusoidal pattern, crossing back and forth across the interface 112. According to various alternative embodiments, the welder 102 is programmed to cause the beam 120 to move in a circular X / Y pattern, which, when combinedwith the absolute X direction movement of the welder 102 relative to the interface 112, may result in a curly q laser pattern (e.g., resembling connected lower case cursive “e”s). Alternatively, the welder 102 may be programmed to cause the beam 120 to move in a figure eight X / Y pattern with the lobes of the eight formed on opposite respective sides of the interface 112. When this figure eight pattern is combined with the absolute X direction movement of the welder 102 relative to the interface 112, the resulting laser pattern on the workpieces 106, 108 is a generally infinite-figure-8 pattern.

[0368] According to various embodiments, the absolute X direction speed of the welder 102 relative to the interface 112 is reduced when employing an X / Y welding laser pattern (including a pure oscillating Y-direction pattern and / or a mixed (e.g., circular or figure eight) X / Y pattern).

[0369] According to various embodiments, the X / Y movement path is controlled, relative to the absolute X direction speed of the welder 102 so that the laser beam 120 maintains a relatively constant absolute speed relative to the workpieces 106, 108. This may help to avoid: (a) dwells and burn-through, which might otherwise occur if the beam 120 moved too slowly, and (b) shallow welds that do not fully penetrate the workpieces 106, 108, which might otherwise occur if the beam 120 moved too fast.

[0370] According to various embodiments, the resulting impingement pattern of the laser beam 120 on the workpieces 106, 108 may improve mixing of metal within the melt pool, which may result in a stronger and / or more homogeneous mixture of parent filler wire 116 and workpiece 106, 108 material in the resulting weld joint 114. For example, the resulting impingement pattern may cause better diffusion of aluminum and / or nickel throughout the weld joint 114. For example, more homogeneous mixing of parent material may improve the ability of filler wire 116 components such as nickel to compensate for the deleterious effect of large concentrations of aluminum in the weld joint 114.

[0371] According to various embodiments, the X / Y welding laser pattern strengthens the weld joint 114 when welding relatively thicker workpieces 106, 108 (e.g., workpieces having a thickness greater than 2.1 mm). According to various embodiments, an X / Y welding laser pattern is used when one or both of the workpieces 106, 108 have a thickness greater than a predetermined value (e.g., 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, and / or 2.5 mm), while lateral oscillation is omitted if both of the workpieces 106, 108 have a thickness equal to or less than the predetermined value.

[0372] In the above-discussed embodiments, the X / Y pattern is typically centered in a Y direction at the middle of the interface 112 (e.g., such that an amplitude of Y direction oscillation is the same to either side of the interface 112, such that the x formed in the center of a figure 8 pattern aligns with the interface 112). However, according to various alternative embodiments, the entire X / Y pattern can be offset laterally (i.e., in the Y direction), for example to the extent and for the reasons discussed above that the beam 120 is laterally shifted (e.g., offsetting the X / Y pattern toward a thicker or stronger or higher melting temperature one of the workpieces 106, 108).16. Shaped Laser Beam

[0373] The laser welder 102 may be configured to generate the laser beam 120 to have a rectangular shaped laser beam spot shape. The laser welder 102 may be configured to generate the laser beam 120 having a square laser beam spot shape. The laser welder 102 may be configured to generate the laser beam 120 having a circular or an elliptical laser beam spot shape. The laser beam spots may have the shape of dots, rings, annuli, other polygons, or short lines. Each laser beam 120 may have its own independent spot shape or may have the same spot shape. Other laser beam spot shapes may be obtained through a laser optical transmission system.

[0374] As shown in FIG. 10, according to one or more embodiments, the laser welder 102 creates a shaped laser beam 120 using a laser generator 300 (e.g., YAG laser, CO2 laser) that generates a seed laser beam 302. The laser welder 102 includes one or more beam splitters 304 for splitting the seed laser beam 302 into a plurality of split beams 120a, a plurality of optical amplifiers 306 for amplifying respective ones of the split beams 120a, and a plurality of phase modulators 308 for modulating respective ones of the split beams 120a. The split beams 120a form a two dimensional array of coherent split beams 120a that recombine to form the coherent shaped beam 120. According to various embodiments, the one or more splitters (304) split the seed beam 302 into an array of split beams 120a comprising (1) at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 250, and / or 500 split beams 120a, (2) less than or equal to 1000, 500, 250, 100, 90, 80, 70, 60, 50, 40, 30, 20, and / or 10 split beams 120a, and / or (3) any number of split beams 120a between any two such upper and lower limits (e.g., between 3 and 1000, between 5 and 500, between 10 and 250). According to various embodiments, the array of split beams 120a may form various array patterns (e.g., a square or rectangular grid (e.g., 10x10 grid of 100 split beams), a hexagonal grid, a circle of split beams 120a), which may be related to or unrelated to an intended shape of the beam 120.

[0375] According to one or more embodiments, the use of parallel amplifiers 306 to amplify the split beams 120a formed from a single seed beam 302 formed by a single laser generator 300 helps to facilitate coherent recombination into the beam 120, which may increase the output power of the beam 120 to a greater extent than with in-series amplifiers. However, according to various alternative embodiments, a plurality of discrete laser generators 300 may be used to form respective beams 120a that are combined to form the beam 120.

[0376] As shown in FIG. 10, the laser welder 102 includes control electronics 310 that are operatively connected to the seed laser generator 300, amplifiers 306, and phase modulators 308 so that the control electronics 310 can individually control an intensity and / or phase of each beam 120a. For example, by individually varying the intensity and / or phase of different beams 120a, the electronics 310 can control the shape of the combined beam 120. As a result, as shown to the right in FIG. 10, the shaped beam 120 has an intensity that varies across its cross-section / spot (i.e., in a cross-section taken perpendicular to an axis / path 314 of the beam 120). According to various embodiments, the laser welder 102 can change the shape of the beam 120 without physically moving optical elements (e.g., lenses, mirrors, the laser generator 300) relative to each other. According to various embodiments, the laser welder 102 can change the shape of the beam 120 in microseconds during a welding process so as to use different beam shapes at different times in the welding process. According to various embodiments, the laser welder 102 can sequence through different beam shapes over time during the welding process.

[0377] According to one or more embodiments, a sensor 312 (e.g., a camera) is used to sense the shape, intensity, and / or phase of the beams 120a and / or beam 120 and provide the sensed information back to the electronics 310 so that the electronics 310 can responsively adjust the beams 120a to better meet the desired beam 120 characteristics (e.g., via a feedback control loop).

[0378] According to one or more embodiments, a laser welder 102 utilizing a laser 300 and components 302, 304, 306, 308, 310, and / or 312 made by Civan can be used.

[0379] According to various embodiments, the combined shaped beam 120 passes through the focusing lens 152 (see FIG. 9). However, according to various alternative embodiments, the focusing lens 152 is omitted or replaced with alternative optical and / or electrical focusing element(s) that focus the shaped beam 120. According to various embodiments, the electronics can shift a focal length of the beam 120 without moving parts (e.g., at 50 MHz).

[0380] As used herein, beam shape means the shape of the beam 120 as viewed in a cross section that is perpendicular to the beam 120’s path / axis 314. As used herein, a spot shape means the shape of the spot formed by the beam 120 impacting the workpiece(s) and / or weld joint 114.

[0381] FIGS. 11 A-D illustrate beam and / or spot shapes formed by the beam 120 according to various embodiments. For example the beam / spot shape(s) formed by the beam 120 and laser welder 102 may include an infinity shaped beam / spot 320 (FIG. 11 A), a spiral shaped beam / spot 322 (FIG. 1 IB), a figure eight shaped beam / spot 324 (FIG. 11C), and / or a closed- loop shaped beam / spot 326 (FIG. 1 ID). The closed-loop shape 326 has a higher intensity along the perimeter defining the closed-loop shape 326 than at some point radially inward of the perimeter (e.g., in the middle area within the loop). The closed-loop shape 326 may be circular (a circular ring) or non-circular (e.g., oval-shaped ring, egg-shaped ring, etc.), and may comprise curves and / or angles (e.g., a square-shaped closed-loop, a polygonal closed-loop, a closed loop combining lines and / or curves). The figure eight shaped beam / spot 324 and / or infinity shaped beam / spot 324 may each comprise multiple adjacent (e.g., touching, overlapping, non-overlapping) closed-loop shapes such as the shape 326. However, as explained above, according to various embodiments, the laser welder 102 can generate any shape desired by individually altering different beams 120a. According to various embodiments, the beam / spot shape may additionally and / or alternatively have a shape in which the intensity is highest in the middle of the beam / spot, and trails off further and further from the middle (e.g., a circular or oval shape with a highest intensity in the middle of the circle or oval).

[0382] According to various embodiments, the beam shape and / or spot shape may have: (a) a lower intensity in the middle of the beam / spot than at a location disposed radially outward from the middle of the beam / spot, (b) a highest intensity at a location spaced from a middle of the beam / spot, and / or (c) a shape (e.g., a spiral) that is not mirror-symmetrical about any axis.

[0383] According to one or more embodiments, and as shown in FIGS. 11 A-D, along at least one line 330 passing through the beam 120, an intensity of the beam 120 increases then decreases then increases. According to various non-limiting embodiments, the line 330 passes through a middle of the beam 120. According to various alternative embodiments, the line 330 does not pass through a middle of the beam 120. According to various embodiments, the line 330 is perpendicular to the beam axis 314, which projects straight into the page in FIGS. 11A- 1 ID. According to various embodiments, the line 330 forms an acute angle with the beam axis314. According to various embodiments, along at least one line 330, the beam intensity increases, then decreases at least three times (e.g., as is the case for lines 330 shown in FIGS. 11B and 11C).

[0384] According to one or more embodiments, the laser welder 102 is configured to vary between different beam / spot shapes over time during a welding process.

[0385] FIG. 12 illustrates an exemplary welded blank 110 in which coated workpieces 106, 108 are joined at a weld joint 114. Structurally important regions of weld joint 114 include the weld joint surfaces 114a (circled in FIG. 12), the weld-joint-to-sheet interfaces 114b (emphasized by added curved lines), and pits or depressions 114c in the surfaces 114a. Stresses tend to concentrate in these regions 114a, 114b, 114c, so it is advantageous to avoid weakening the weld joint 114 in these regions 114a, 114b, 114c.

[0386] Conventional laser welding laser beams have circular or oval shapes and focus laser energy toward the middle of the shape / spot. When welding aluminum-coated workpieces 106 and 108 using such conventional laser beams, aluminum from the coating tends to become dispersed inthe weld joint 114, including at the important regions 114a, 114b, 114c. Dispersion of aluminum into these regions 114a, 114b, 114c tends to weaken the weld joint 114. In contrast, by using shaped laser beams / spots and / or by changing the shape of the laser beam / spot over time, as explained above, it is believed that the welding process can tend to cause the aluminum from the coating to accumulate less in the regions 114a, 114b and / or 114c and more in less structurally significant regions of the weld joint 114 (e.g., in the middle of the weld joint 114 where stresses are lower).

[0387] As explained above, various embodiments utilize filler wire 116 with a composition (e.g., via Ni and / or Cr additives) that binds with aluminum in the weld joint 114 to reduce the extent to which aluminum might otherwise weaken the weld joint 114. Alternatively, the filler wire 116 may minimize or even omit such additives. For example, according to one or more embodiments in which the shaped laser beam 120 reduces an adverse impact of aluminum in the weld joint 114, a steel filler wire 116 with little or no Ni or Cr may be used. In such embodiments, the steel filler wire 116 may provide gap compensation (i.e., to fill the gap at the interface 112 of the be formed weld joint 114) but not be specifically intended to metallurgically account for the presence of aluminum coating in the weld joint 114.

[0388] While various embodiments utilize filler wire, other embodiments alternatively use filler powder or no filler at all. For example, according to one or more embodiments, the use of shaped laser beam 120 facilitates the welding of aluminum-coated workpieces 106, 108 toform strong welded assemblies 110 without using a filler (e.g., without using filler wire or filler powder). In such a non-filler embodiment, the weld joint 114 consists of material from the workpieces 106, 108 and unavoidable impurities.

[0389] According to one or more embodiments, the same laser system 102 (including the same laser generator 300) is used to both ablate the aluminum-silicon coating 118, 106a, 108a and then weld the ablated workpieces 106, 108 together. In such an embodiment, the shape, focus, and / or intensity of the beam 120 can first be set so as to facilitate ablation, and then be altered by the electronics 310 and / or additional electric or optical elements so as to weld the workpieces 106, 108 together. According to various embodiments, the ablation and welding can occur during a single pass of the system 102 by the interface 112 between the workpieces 106, 108, for example by rapidly switching between an ablation beam 120 and a welding beam 120 as the beam 120 moves along the interface 112. Alternatively, the system 102 may first carry out the ablation along the entire interface 112 during a first pass over the full length of the interface 112, and then weld the workpieces 106, 108 together during a second pass over the length of the interface 112 so as to form the weld joint 114.D. WELD ASSEMBLY / WELDED BLANK 110

[0390] According to various embodiments, the above-discussed welding process results in a weld assembly or welded blank 110 with a weld joint 114 formed between the parent steel workpieces 106, 108. The weld joint 114 may be a butt joint (e.g., where two steel workpieces are placed together in the same plane), lap joint (e.g., overlapping configuration with one workpiece edge being on top of the other workpiece’s edge), tee-joint (e.g., when two steel workpieces intersect at a 90° angle), edge joint, and / or corner joint (i.e., when two steel workpieces meet in the ‘corner’ in either an open or closed manner — forming an ‘L’ shape).

[0391] According to various embodiments, the weld joint 114 comprises a mixture of material from the work piece 106, workpiece 108, and filler wire 116. The relative concentrations of parent material from the workpiece 106, workpiece 108, and filler wire 116 in the resulting weld pool and weld joint 114 depends on various factors (e.g., whether the filler wire 116 is pre-heated, the relative melting points of the workpieces 106, 108 and filler wire 116, the orientation and location of the laser beam 120, the feed rate of the filler wire 116, absolute and relative thicknesses of the workpieces 106, 108, thickness of the filler wire 116, laser power, welding speed, etc.). According to various embodiments, a composition of the weld joint 114 (and weld pool) comprises (a) at least 5, 10, 15, 20, 25, 30, 35, 40,45, 50, 55, 60, 65, 70, and / or 75% material from the filler wire 116, (b) less than or equal to 90, 85, 80,75, 70„ 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, and / or 5% material from the filler wire 116, and / or (c) between any two such values (e.g., between 5 and 90% material from the filler wire). According to various embodiments, a remainder of the material of the weld joint 114 (and weld pool) comprises material from the work pieces 106, 108 (plus impurities resulting from the welding process).

[0392] According to various embodiments, the concentration of filler wire 116 in the weld joint 114 will be different for a high-strength-steel-to-high-strength-steel weld joint 114 than for a high-strength-steel-to-low-strength-steel weld joint 114.

[0393] In one or more embodiments, the tensile strengths of the weld joint 114 and the workpieces 106, 108 (after heat treatment) are equal to or greater than 1200 MPa. In one or more embodiments, the tensile strengths of the workpieces 106, 108 (after heat treatment) are equal to or greater than 1500 MPa.

[0394] In one or more embodiments, the hardnesses of the weld joint 114 and the workpieces 106, 108 are equal to or greater than 400HV.

[0395] According to various embodiments in which the workpieces 106, 108 are coated and the coatings 118 were not completely removed prior to the welding procedure, material from the coatings 118 may comprise (a) at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0, 3.5, 4.0, and / or 4.5 % of the weld joint 114 (and weld pool), (b) less than or equal to 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and / or 0.1% of the weld joint 114 (and weld pool), and / or (c) between any two such values (e.g., 0.1 and 5.0 %, 1-2%, etc.).

[0396] According to various embodiments, the welding process may result in the workpieces 106, 108 contributing equally or unequally to the material of the weld joint 114 (and weld pool). Factors that may result in an unequal share include, without limitation, the relative compositions and thicknesses of the workpieces 106, 108, the offset of the laser beam 120 resulting in preferential melting of the workpiece 106, 108 receiving more laser energy, etc.). According to various embodiments, an amount of material in the weld joint 114 (and weld pool) originating from one of the workpieces 106, 108 may exceed an amount of material in the weld joint 114 (and weld pool) originating from the other of the workpieces 106, 108 by X % in absolute terms of the total composition of the weld joint 114 (and weld pool). According to various embodiments, X is (a) at least 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, and / or 40, (b) less than 50, 45, 40, 35, 30, 25, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7,6, 5, 4, 3, 2, and / or 1, and / or (c) between any two such values (e.g.,between 0 and 90, between 5 and 25, etc.). For example, if the weld joint 114 comprises 30% material from workpiece 106, 40% material from workpiece 108, and 28% material from the filler wire 116, and 2% material from the coatings 118 of the workpieces 106, 108, then X is 10 (i.e., 40% exceeds 30% by 10 absolute %).

[0397] According to various embodiments, the filler wire 116 comprises, on a cumulative bulk weight percentage over the length of the weld joint 114, (1) at least 5, 10, 15, 20, 25, and / or 30% of the weld joint 114, (2) less than 50, 45, 40, 35, 30, 25, and / or 20% of the weld joint 114, and / or (3) between any two such values (e.g., between 5 and 50% of the weld joint 114, between 10 and 40% of the weld joint 114).

[0398] According to various embodiments, depending on the compositions of the workpieces 106, 108 and filler wire 116, the presence of any coatings 118, and their relative contributions to the weld joint 114, the weld joint 114 (which does not include the heat affected zone (HAZ)) may include the following weight-based concentrations of any of the following elements (including the composition contributed by the coatings, if present):• Carbon: According to one or more non-limiting embodiments, the carbon concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.05%, 0.08%, 0.1%, 0.15%, 0.2%, and / or 0.22%;• less than or equal to 0.5%, 0.45%, 0.3%, 0.25%, 0.2%, 0.15%, and / or 0.1%;• about 0.118%; and / or• between any two such lower and upper values (e.g., 0.05% < C < 0.5% 0.08% < C < 0.25%; 0.15% < C < 0.25%)).• According to various embodiments, such presence of carbon in the weld joint 114 may advantageously strengthen the weld joint 114 and / or function as a gammagenic element (a.k.a. austenitic stabilizer element) to compensate for the presence of alphagenic elements such as Cr, Mo, Si, Al and Ti in the weld joint 114. Conversely, according to various embodiments, the carbon concentration is limited so as to avoid known disadvantages of high carbon contents (e.g., avoiding brittleness).• Manganese: According to one or more non-limiting embodiments, the manganese concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.001%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and / or 3.0%;• less than or equal to 5.0%, 4.0%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, and / or 0.2%; and / or• between any two such lower and upper values (e.g., 0.001% < Mn < 5.0%, Mn 0.1% < Mn < 5.0%; 0.5% < Mn < 2.0%; 0.8% < Mn < 1.8%)).• According to various embodiments, such presence of manganese in the weld joint 114 may function as a gammagenic element (a.k.a. austenitic stabilizer element) to compensate for the presence of alphagenic elements such as Cr, Mo, Si, Al and Ti in the weld joint114. According to various embodiments, such presence of manganese in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may contribute to the strength, hardness, and / or hardenability of the weld joint 114 (and / or parent workpieces 106, 108).Silicon: According to one or more non-limiting embodiments, the silicon concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, and / or 0.5%;• less than or equal to 1.5%, 1.0%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.05%, and / or 0.01%; and / or• between any two such lower and upper values (e.g., 0.0% < Si < 2%; 0.001% < Si < 1%; 0.01% < Si < 1.0%; 0.1% < Si < 1.0%).• According to various embodiments, such presence of silicon in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may improve the corrosion resistance of the weld joint 114 (and / or parent workpieces 106, 108).Nickel: According to one or more non-limiting embodiments, the nickel concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0%, 5.0%, 7.5%, 10.0%, 12.5%, and / or 15%;• less than or equal to 20.0%, 15.0%, 12.5%, 10.0%, 7.5%, 5.0%, 4.0%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, and / or 0.01%; and / or• between any two such lower and upper values (e.g., 0.0% < Ni < 20%; 0.001% < Ni < 15%; 0.01% < Ni < 15%; 0.1% < Ni < 15%; 1.0% < Ni < 3.0%)).• According to various embodiments, such presence of nickel in the weld joint 114 may function as a gammagenic element (a.k.a. austenitic stabilizer element) to compensate for the presence of alphagenic elements such as Cr, Mo, Si, Al and Ti in the weld joint114. According to various embodiments, such presence of nickel in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may function as a toughening element. According to various embodiments, such presence of nickel, for example in combination with chromium, in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may produce greater hardenability, higher impact strength, and greater fatigue resistance.Chromium: According to one or more non-limiting embodiments, the chromium concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0%, 5.0%, 7.5%, 10.0%, 12.5%, and / or 15%;• less than or equal to 20.0%, 15.0%, 12.5%, 10.0%, 7.5%, 5.0%, 4.0%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Cr < 20%; 0.001% < Cr < 20%, 0.01% < Cr < 20%, 2.0% < Cr < 6.0%; 3.0% < Cr < 5.0%; Cr < 5.0%; Cr < 2.5%; Cr < 1.0%; Cr < 0.1%).• According to various embodiments, such presence of chromium in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may improve the corrosion resistance, hardenability, high-temperature strength, and abrasion resistance of the weld joint 114 (and / or parent workpieces106, 108). According to various embodiments, such presence of chromium, for example in combination with nickel, in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may produce greater hardenability, higher impact strength, and greater fatigue resistance.Molybdenum: According to one or more non-limiting embodiments, the molybdenum concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, and / or 1.0%;• less than or equal to 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Mo < 3.0%; 0.0% < Mo < 1.5%; 0.4< Mo < 1.1%; 0.0< Mo < 0.65%).• According to various embodiments, such presence of molybdenum in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may improve hardness and hardenability.Aluminum: According to one or more non-limiting embodiments, the aluminum concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0%, 5.0%, 7.5%, and / or 9.0%;• less than or equal to 10.0%, 7.5%, 5.0%, 4.0%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Al < 10.0%; 0.5% < Al < 2.0%).• According to various embodiments, such presence of aluminum in the weld joint 114 may result from the melting of the aluminum-containing coating of the workpiece(s) 106, 108 into the weld pool and weld joint 114. Excess aluminum is generally detrimental to the strength of the weld joint 114, so the aluminum concentration is preferably low. As explained herein, gammagenic element(s) (a.k.a. austenitic stabilizerelement(s)) may also be included in the weld joint 114 to compensate for the presence of alphagenic elements such as aluminum.Niobium: According to one or more non-limiting embodiments, the niobium concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, and / or 0.15%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Nb < 0.2%).• According to various embodiments, such presence of even a small concentration of niobium in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may increase the yield strength and tensile strength.Titanium: According to one or more non-limiting embodiments, the titanium concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, and / or 0.15%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Ti < 0.2%).• According to various embodiments, such presence of titanium in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may have a similar effect as discussed herein with respect to vanadium and / or niobium.Sulfur: According to one or more non-limiting embodiments, the sulfur concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, and / or 0.04%;• less than or equal to 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < S < 0.05%).• Sulfur is typically present in the weld joint 114 and the parent workpiece(s) 106, 108 as an iron impurity whose concentration is preferably limited so as to be less than or equal to 0.05%.Copper: According to one or more non-limiting embodiments, the copper concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, and / or 2.0%;• less than or equal to 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5%, 0.4%, 0.3%, 0.2%, 0.15%, 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Cu < 3.0%; 0.001% < Cu < 1.0%).• According to various embodiments, such presence of copper in the weld joint 114 may function as a gammagenic element (a.k.a. austenitic stabilizer element) to compensate for the presence of alphagenic elements such as Cr, Mo, Si, Al and Ti in the weld joint 114.Phosphorus: According to one or more non-limiting embodiments, the phosphorus concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < P < 0.1%).• Phosphorus is typically present in the weld joint 114 and the parent workpiece(s) 106, 108 as an iron impurity whose concentration is preferably limited so as to be less than or equal to 0.1%.Vanadium: According to one or more non-limiting embodiments, the vanadium concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.15%, and / or 0.2%;• less than or equal to 0.2%, 0.15%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < V < 0.3% (e.g., 0.001% < V < 0.3%, 0.01% < V < 0.3%).• According to various embodiments, such presence of vanadium in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may have a similar effect as discussed herein with respect to titanium and / or niobium.Boron: According to one or more non-limiting embodiments, the boron concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, and / or 0.009%;• less than or equal to 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < B < 0.010%).• Boron is typically present in the weld joint 114 if one or both of the work piece(s) 106, 108 are boron steel.Cobalt: According to one or more non-limiting embodiments, the cobalt concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, and / or 0.09%;• less than or equal to 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper values (e.g., 0.0% < Co < 0.1%; 0.001% < Co < 0.1%; 0.01% < Co < 0.1%).According to various embodiments, such presence of cobalt in the weld joint 114 (and / or the parent workpiece(s) 106, 108) may increase hardness, heat and abrasion resistance, and / or wear resistance.• Nitrogen: According to one or more non-limiting embodiments, the nitrogen concentration (if present) in the weld joint 114 may be:• greater than or equal to 0.0%, 0.001%, 0.002%, 0.003,%, 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, and / or 0.015%;• less than or equal to 0.02%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, and / or 0.001%; and / or• between any two such lower and upper limits (e.g., 0.0% < N < 0.02%; 0.0% < N < 0.01%; 0.0% < N < 0.009%; 0.003% < N < 0.010%; ~ 0.005%).• According to various embodiments, such presence of nitrogen in the weld joint 114 may function as a gammagenic element (a.k.a. austenitic stabilizer element) to compensate for the presence of alphagenic elements such as Cr, Mo, Si, Al and Ti in the weld joint114. However, nitrogen in the weld joint 114 may also result from the presence of nitrogen as an impurity in the parent workpiece(s) 106, 108 and / or filler wire 116.According to various embodiments, any combination of one or more of the above listed elements in any of the above-discussed concentrations (be it minimum, maximum, or a range) is explicitly contemplated. Any one or more of the above-listed elements may be omitted from the weld joint 114 according to various non-limiting embodiments. According to various nonlimiting embodiments, the remaining composition may comprise or consist of iron, trace elements, and impurities.

[0399] According to one or more embodiments, the weld joint 114 includes iron, carbon, aluminum, nickel, chromium, silicon, and molybdenum. The weld joint 114 may also include impurities such as phosphorus and / or sulfur. The weld joint 114 may also include any one or more of the other elements discussed in the above paragraph.

[0400] In one or more embodiments, the weld joint 114 of the welded blank 110 includes a partially or fully martensite microstructure prior to further heating or heat treatment processes. For example, the microstructure in the weld joint 114 (i.e., including the weld joint 114 between Usibor® and Ductibor®) prior to a subsequent heating procedure (of the hot forming / stampingprocedure) may include a mixture of martensite, bainite, ferrite, and / or retained austenite. According to various embodiments, the weld joint 114 of the welded blank 110 may have a microstructure, before further hot stamping or heat treatment, that is at least 60, 70, 80, 90, and / or 95% martensite (e.g., 90+% martensite). According to various embodiments, the weld joint 114 of the welded blank 110 may also include, before further hot stamping or heat treatment, ferrite (e.g., delta ferrite). According to various embodiments, a ferrite concentration Ferritewr, within the weld joint 114, before further hot stamping or heat treatment, is (a) greater than 0.0, 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, and / or 2.5%, (b) less than 10, 9, 8, 7, 6, 5, 4, 3, and / or 2.5%, and / or (c) between any such values (e.g., 0.0 < Ferritewr < 5.0%; 0.1 < Ferritewr < 5.0%; 0.0 < Ferritewr < 10.0%).

[0401] As used here, the term weld joint 114 means only the portions of the parent materials that melted to form a weld melt / pool and resolidified to form the weld joint 114. The weld joint 114 does not include the heat affected zone (HAZ) adjacent to the actual weld joint 114.

[0402] According to various embodiments, the weld joint 114 provides a weld assembly 110, which after heat treatment, has an ultimate tensile strength of 1300MPa or more (or breaks in the lower strength of the base workpieces 106, 108), a hardness of 400 HV or more across the weld joint 114 (for high-strength-to-high-strength weld joints 114), an elongation of at least 4.5%, an undercut of less than 10% per side and less than 15% total, and an overfill of less than 10% per side and less than 15% total.1. Homogeneity Of Weld Joint

[0403] To enhance weld joint 114 strength, a homogenous distribution of material in the weld joint 114 can be helpful. For example, when laser welding aluminum coated workpieces 106, 108, aluminum and silicon from the coating tends to pool near the corners of the weld joint 114 (i.e., near where the surface of the weld joint 114 meets the surface of the workpieces 106, 108) because these corners are near to the coating source of such aluminum and silicon. Such high concentrations of pollutants such as Al near such corners can adversely affect the strength of the weld joint, and are therefore preferably avoided by increasing the homogeneity of the aluminum and / or silicon within the weld joint 114.

[0404] Such homogeneity can be achieved in a number of ways, such as thorough mixing of molten weld material in the weld melt. Such mixing can be achieved in a number of ways, such as applying high heat and / or high power density to the weld pool during the welding process. For example, during laser welding of the joint 114 using filler wire 116, keyhole welding can be used to achieve thorough mixing of molten material in the weld pool. In variousembodiments, the power density of the laser to achieve keyhole welding is (a) at least 105W / cm2, 105 5W / cm2, IO5 75W / cm2, 106W / cm2, IO6 25W / cm2, 106 5W / cm2, IO6 75W / cm2, and / or 107W / cm2, (b) less than or equal to 107W / cm2, 10675W / cm2, 106 5W / cm2, 106 25W / cm2, 106W / cm2, 105 75W / cm2, and / or 105 5W / cm2, and / or (c) between any two such values (e.g., 105- 107W / cm2, 105 5-107W / cm2, 106-107W / cm2). In various embodiments, sufficient heat is applied during the weld process to achieve convection mixing of the weld material in the weld pool. In various embodiments, the weld speed can be slowed to achieve enhanced mixing of weld material within the weld pool. For example, in various embodiments, the weld speed may be less than 100 mm / s. It should be appreciated that reduced weld speed can negatively impact product throughput. Therefore, in various embodiments, the weld speed can be greater than a lower threshold. In various embodiments, the weld speed is between 60 mm / s and 100 mm / s. In another embodiment, the weld speed is between 80 mm / s and 100 mm / sec.

[0405] In various embodiments, it may be particularly desirable to enhance mixing of aluminum and / or silicon in the weld joint 114. In such embodiment, a binding material (e.g., Ni) of sufficient quantity may be used to reduce concentrated areas of aluminum and / or silicon in the weld joint 114. For example, in various embodiments, nickel is provided in sufficient quantity in the filler wire to pull aluminum away from itself (and bind to the nickel instead). In various embodiments, for example, at least 10% nickel is provided in the wire 116.

[0406] In various embodiments, localized areas of high concentration of aluminum in the weld joint 114 is avoided.

[0407] According to various embodiments, the laser welding process and / or filler wire 116 composition results in a generally homogeneous distribution of aluminum and silicon from the aluminum based coating(s) 118 of the workpieces 106, 108 into the weld joint 114. For example, high concentrations of nickel (and / or other gammagenic elements and / or chromium) in the weld joint 114 (as a result of high concentrations of such elements in the filler wire 116) may bind to aluminum in the weld joint 114 and cause the aluminum to disperse relatively homogeneously throughout the weld joint 114.

[0408] According to one or more embodiments, aluminum throughout the weld joint 114 may have a total / bulk concentration Alwr of (a) at least 0.5, 0.6, 0.7, 0,8 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and / or 1.9 %, (b) not more than 3.0, 2.5, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.1, 0.9, and / or 0.8 %, and / or between any such values (e.g., 0.5-3.0%, 0.5-2.0%, 0.75-2.0%, 1.0-2.5%). Despite such a high total concentration of aluminum, the aluminum is distributed relatively evenly. This homogeneity is determined by using a scanning electronmicroscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) to determine a local aluminum concentration within any square area of dimension L mm x L mm entirely within any cross section of the weld joint 114. According to various embodiments, L is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, and / or 0.2 mm. According to various embodiments, a local concentration of aluminum within any such L x L area within a crosssection of the weld joint 114 is less than 10, 9, 8, 7, 6, 5, 4, 3, 2.5, 2.0, and / or 1.5%. According to various embodiments, a local concentration of silicon within any such L x L area within the weld joint 114 is less than 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and / or 1.0%. According to various embodiments, homogeneity of aluminum and / or silicon within such ranges may result in a strong weld joint 114.

[0409] According to various embodiments, a local aluminum concentration within any such L x L area within any cross section of the weld joint 114 is less than 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1.5 times the bulk aluminum concentration Alwr throughout the weld joint 114. According to various embodiments, a local silicon concentration within any such L x L area within the weld joint 114 is less than 10, 9, 8, 7, 6, 5, 4, 3, 2, and / or 1.5 x a bulk silicon concentration Siwr within the weld joint 114. According to various embodiments, homogeneity of aluminum and / or silicon within such ranges may result in a strong weld joint 114.

[0410] According to various non-limiting embodiments, advantageous homogeneity of aluminum within the weld joint 114 results from nickel being present in the weld joint 114 at a bulk concentration of at least 2, 3, and / or 4%.E. Heat Treatment And Hot Stamping

[0411] In one or more embodiments, the weld assembly 110 then undergoes a heat treatment process that includes heating the weld assembly in a furnace, optionally hot-stamping the weld assembly, and then cooling the weld assembly (or stamped part) at a controlled speed to provide a desired heat treatment (e.g., quenching, annealing, a mixture of quenching and annealing at different locations on the weld assembly) to create a heat-treated and / or hot-stamped part.1. Heating

[0412] In one or more embodiments, the heating process during the heat treatment process heats the weld assembly 110 in a furnace to a desired / predetermined temperature, e.g., a temperature that exceeds the AC3 temperatures of both parent workpieces 106, 108 and the weld joint 114, which results in the weld assembly 10 becoming fully austenitic. According to various alternative embodiments, the weld assembly 110 is heated to a temperature that exceeds the AC3 temperature of the parent workpieces 106, 108, but is below the AC3 temperature ofthe weld joint 114, which results in a heated blank / assembly that is austenitic in the regions of the parent workpieces 106, 108, but not fully austenitic in the weld joint 114.

[0413] The furnace may be configured to heat multiple weld assemblies therein. The furnace may comprise a continuous or discontinuous conveyor for moving the weld assemblies through progressively hotter zones of the furnace.2. Hot Stamping

[0414] During a transferring procedure, the heated weld assembly 110 may be transferred (using a transfer system) to a hot-stamping press. During a forming and / or quenching procedure, the heated weld assembly 110 is formed and quenched in the press to form a hot-stamped part. The press may include a cooling system for quenching and includes a pair of dies for forming the heated weld assembly into the desired cross-sectional shaped configuration of the resulting hot stamped weld assembly / part.

[0415] According to various embodiments, the upper and / or lower surfaces of the hot stamping dies may include groove(s) / recess(es) that are aligned with the weld joint 114 to accommodate an overfilled or convex weld joint 114 while still having the adjacent die surfaces contact the base workpieces 106, 108. Such die grooves may beneficially reduce the amount of strain and stress that the hot stamping process imparts on the weld joint 114. Alternatively, such die grooves are omitted from the dies, and the stamping process tends to compress convexities and overfills of the weld joint 114, which may cause material flow form the weld joint 114 toward the base metal workpieces 106, 108 during the hot stamping process.3. Cooling

[0416] The weld assembly 110 (or hot-stamped part, if hot stamping is used) is then cooled at a controlled rate.

[0417] The controlled rate may be the same throughout the weld assembly / hot-stamped part.

[0418] According to various embodiments, the cooling involves quenching, which hardens the workpiece 106 and / or 108. According to various embodiments formed from a combination of high and low strength workpieces 106, 108, the cooling process hardens the high strength workpiece 106, 108 more than the low strength workpiece 106, 108.

[0419] Alternatively, different portions of the weld assembly / hot-stamped part 110 may be cooled at different rates (e.g., via selective heating and / or cooling of different portions of a hot stamping die, air gaps in the die (see U.S. Patent App. Pub. No. 2022-0105553 Al), etc.).

[0420] After the cooling process, the weld assembly 110 may have a completely or partially martensitic microstructure. In one or more embodiments, there may be small trace amounts ofother microstructures, but the vast majority of the weld assembly for workpieces 106, 108 formed from high-strength steel is martensitic microstructure after the heat treatment process.

[0421] The microstructure in the weld joint 114 (e.g., including the weld joint 114 between Usibor® and Ductibor®) after the heating procedure (of the hot forming / stamping procedure) may be completely or almost completely austenite (e.g., at least 90, 95, 96, 97, 98, and / or 99% austenite). The microstructure in the weld joint 114 after the hot forming / stamping procedure and / or quenching procedure may be completely, almost completely, or mostly martensite. For example, the microstructure in the weld joint 114 (e.g., including the weld joint 114 between Usibor® and Ductibor®) after the heat treatment process may include a mixture of martensite (e.g., at least 90, 95, 96, 97, 98, and / or 99% martensite), bainite, ferrite, and / or retained austenite. According to various embodiments, the ferrite concentration Ferritewr, within the weld joint 114, after the heat treatment process, is (a) greater than 0.0, 0.1, 0.2, 0.5, 1.0, 1.5, 2.0, and / or 2.5%, (b) less than 10, 9, 8, 7, 6, 5, 4, 3, and / or 2.5%, and / or (c) between any such values (e.g., 0.0 < Ferritewr < 5.0%; 0.1 < Ferritewr < 5.0%; 0.0 < Ferritewr < 10.0%). Alternatively, the weld joint, after the heat treatment process, may be ferrite free.

[0422] The hardness of the weld joint 114 (including two high strength steel / two Usibor® workpieces), for example, prior to the heating procedure (of the hot forming / stamping procedure) may be higher than the hardness of the base steel material of the workpiece(s) 106, 108. This may be due to the laser welding procedure, the use of filler wire 116 and its material, and also rapid quenching procedure after the hot stamping / forming procedure. The hardness of the weld joint 114 (including a high strength steel / Usibor® workpiece and a low strength steel / Ductibor® workpiece), for example, prior to the heating procedure (of the hot forming / stamping procedure) may be higher than the hardness of the high strength steel / Usibor® base workpiece 106, 108 and the hardness of the low strength steel / Ductibor® base workpiece 106, 108.

[0423] The hardness of the weld joint 114 (including two high strength steel / two Usibor® workpieces), for example, after the hot stamping / forming procedure and / or the quenching procedure may be equal to or higher than the hardness of the base steel (i.e., high strength steel / two Usibor®) material. The hardness of the weld joint 114 (including a high strength steel / Usibor® workpiece and a low strength steel / Ductibor® workpiece), for example, after the hot stamping / forming procedure and / or the quenching procedure may be lower than the hardness of the high strength steel / Usibor® base workpiece and higher than the hardness of the low strength steel / Ductibor® base workpiece.

[0424] The formed and quenched / cooled weld assembly 110 (e.g., stamped part, quenched part) may be transferred (using another transfer system) for other stations for further cooling and / or further processing.4. Machining / Trimming

[0425] According to various embodiments, before and / or after the heat treatment and / or hot-stamping, the welded assembly 110 (or hot-stamped part or quenched part) is trimmed (e.g., via laser cutting, machining, die stamping) to provide a shape and edges closer to the final part being manufactured. According to various embodiments, this trimming may be used to remove registration tabs that were used to locate the workpieces 106, 108 relative to each other and / or the manufacturing assembly (e.g., laser welder 102) during manufacture.F. HEAT-TREATED PART / HOT- STAMPED PART

[0426] The laser welded assembly, after optional hot-stamping and optional heat treatments, may be used for or may include body structural components of the automobile such as an A-Pillar / assembly, A-Pillar reinforcement member / assembly, side member / assembly, B- Pillar, B-Pillar reinforcement member / assembly, C-Pillar, C-Pillar reinforcement, hinge pillar / assembly, roof rail member / assembly, header member / assembly, roof bow member / assembly, door ring member / assembly, double door ring member / assembly, front rail member / assembly, rear rail member / assembly, side member reinforcement member / assembly, rocker rail member / assembly, rocker panel member / assembly, fire wall upper member / assembly, fire wall lower member / assembly, fire wall reinforcement member / assembly, tunnel member / assembly, tunnel reinforcement member / assembly, side impact beam front door member / assembly, side impact beam rear door member / assembly, floor, floor cross members, body sides, body inners, inside of rear or front wheelhouse fenders, dash panels, door inners, hood inners, tailgates, etc.

[0427] The laser welded assembly 110 may include or may be used for body structural components of the automobile such as a front bumper member / assembly, rear bumper member / assembly, door beam member / assembly, rocker panel reinforcement member / assembly, belt line reinforcement member / assembly, roof rail reinforcement member / assembly, carrier understructure member assembly, mounting front wall member / assembly, etc.

[0428] The laser welded assembly 110 may include or may be used for body structural components of the automobile such as standard Electric Vehicle (EV) specific components / assembly, Battery-powered Electric Vehicle (BEV) specificcomponents / assembly, etc. For example, these EV or BEV specific components / assembly may include side member / assembly of battery tray, cross member / assembly of battery tray, Reinforcement of battery tray / assembly, comer reinforcement member / assembly, battery tray cover member / assembly, battery tray cover reinforcement member / assembly, etc. These are just a few examples. In another embodiment, the laser welded assembly may include other structural components of the automobile.1. Hardness Variation

[0429] According to various embodiments, when a low strength workpiece 106, 108 is welded to a high strength workpiece 106, 108, a hardness of the resulting weld joint 114 (after heat treatment / hot pressing / quenching) varies significantly across the weld joint 114. For example, according to various embodiments, a maximum hardness variation across a crosssection (and / or all cross sections, either individually in aggregate) of the weld joint 114 is greater than 20, 25, 30 and / or 35% of an average hardness of the weld joint 114 within that cross-section. According to various embodiments, the hardness is measured using the Vickers hardness test according to the standard NF EN ISO 650701 with (a) the tests performed transversely across a cross-section of the weld joint 114 (e.g., such as the cross-section shown in FIG. 12), using a test force of 0.5 kgf (HV0.5), (b) the hardness being measured along three lines located respectively at 14, ’A, and3 / 4 of the thickness of the weld joint 114, and (c) each measurement being taken in regular steps according to NF ISO 6507-1, starting from the central axis of the weld joint 114. Despite the large hardness variation, it was found according to various embodiments that the weld joint 114 remains strong, with the failure point in the low strength workpiece 106, 108, rather than in the weld joint 114.2. Door Ring

[0430] According to various embodiments, the hot-stamped part 110 is a door ring made up of more than two workpieces 106, 108. According to various embodiments, the abovedescribed materials and methods may be incorporated into the manufacture of the door rings disclosed in PCT Publication No. WO / 2022 / 213219 (“System For Welding Multiple Blanks Into A Component”) and / or in U.S. Provisional Application No. 63 / 643,947, titled “Method of Tracking A Blank Edge For Laser Cutting,” filed May 4, 2024, the entire contents of each of which are hereby incorporated herein by reference.

[0431] According to various embodiments, the door ring may be formed from steel workpieces 106, 108 having the same or different material grade and the same or different thickness. According to various embodiments, the door ring comprises overlappingcombinations of workpieces 106, 108 (e.g., four cumulative workpieces 106, 108, each of which are laser welded to two adjacent ones of the workpieces 106, 108). According to various embodiments, the workpieces 106, 108 making up the door ring have different strengths, compositions, and / or thicknesses than other of the workpieces 106, 108 of the door ring.

[0432] According to various embodiments, adj acent high strength workpieces 106, 108 of the door ring are welded using a relatively high carbon filler wire 116, as discussed above (e.g., ER330). Conversely, when a high strength workpiece 106, 108 is welded to an adjacent low strength workpiece 106, 108 of the door ring, a relatively low carbon filler wire 116 is used, as discussed above (e.g., 316L). As a result, different composition filler wires 116 are used for different ones of the weld joints 114 across the overall part comprising three or more workpieces 106, 108 (e.g., a door ring).

[0433] According to various embodiments two of the workpieces 106, 108 are welded and hot stamped (e.g., to form a hot stamped hinge pillar, A-pillar, or B-pillar) and then subsequently welded to an additional workpiece 106, 108 (or workpieces 106, 108) (e.g., rocker), which were similarly previously welded together and hot stamped.G. MISCELLANEOUS

[0434] The illustration of the embodiments of the present patent application should not be taken as restrictive in any way since a myriad of configurations and methods utilizing the present patent application can be realized from what has been disclosed or revealed in the present patent application. The systems, features and embodiments described in the present patent application should not be considered as limiting in any way. The illustrations are representative of possible construction and mechanical embodiments and methods to obtain the desired features. The location and / or the form of any minor design detail or the material specified in the present patent application can be changed and doing so will not be considered new material since the present patent application covers those executions in the broadest form.

[0435] According to various embodiments, each and every portion of each and every above-discussed embodiment can be used with each and every other portion of each and every other above-discussed embodiment.

[0436] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations,elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0437] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0438] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0439] Terms of degree such as “generally,” “substantially,” “approximately,” and “about” may be used herein when describing the relative positions, sizes, dimensions, or values of various elements, components, regions, layers and / or sections. These terms mean that such relative positions, sizes, dimensions, or values are within the defined range or comparison (e.g., equal or close to equal) with sufficient precision as would be understood by one of ordinary skill in the art in the context of the various elements, components, regions, layers and / or sections being described.

[0440] The foregoing illustrated embodiments have been provided to illustrate the structural and functional principles of the present patent application and are not intended to belimiting. To the contrary, the present patent application is intended to encompass all modifications, alterations and substitutions within the spirit and scope of the appended claims.

[0441] The present patent application and its various embodiments as described above uniquely address the observed, noted and researched findings and improve on the prior and current state of the art systems. The listed products, features and embodiments as described in the present patent application should not be considered as limiting in any way.

[0442] Although the present patent application has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that the present patent application is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. In addition, it is to be understood that the present patent application contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

[0443] To the extent there is any interpretational or disclosure conflict between the explicit disclosure in this application and any incorporated-by-reference material, the explicit disclosure in this application governs.

Claims

What is claimed is:

1. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; and moving a laser beam along the interface to melt a portion of at least one of the steel workpieces to form a melt pool that solidifies to form a weld joint between the workpieces, wherein the laser beam is laterally offset from a center of the interface by an average offset distance Y’ during said moving, and wherein Y’ is at least 0.1 mm; and feeding a filler wire into the melt pool during said moving.

2. The method of claim 1, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating melting into the melt pool and forming part of the weld joint; and the filler wire comprises iron and at least 10% Ni.

3. The method of claim 1, wherein: the first workpiece is thicker than the second workpiece, and the lateral offset is toward a first workpiece side of the interface.

4. The method of claim 3, wherein a magnitude of Y’ is selected based on an absolute thickness difference between the workpieces.

5. The method of claim 3, wherein a magnitude of Y’ is selected based on a thickness of the first workpiece relative to a thickness of the second workpiece.

6. The method of claim 1, wherein a carbon concentration of the first workpiece is higher than a carbon concentration of the second workpiece, and wherein the lateral offset is toward a first workpiece side of the interface.

7. The method of claim 1, wherein the lateral offset Y’ is toward a higher post-heat- treatment-strength one of the workpieces.

8. The method of claim 1, wherein said feeding of the filler wire comprises feeding the filler wire at a location that is laterally offset from the center of the interface by same extent as the laser beam.

9. The method of claim 1, wherein said feeding of the filler wire comprises feeding the filler wire at a location that is laterally offset from the center of the interface to a different extent than the laser beam’s offset Y’ .

10. The method of claim 1, further comprising oscillating the laser beam laterally during said moving such that an instantaneous lateral offset varies as the laser beam moves along the interface.

11. The method of claim 1, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

12. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between edges of the first and second workpieces, wherein the interface has first and second ends, wherein the edge of one of the workpieces diverges from the edge of the other of the workpieces at the first end such that a first vertex is formed between the edges at the first end, and wherein the edge of one of the workpieces diverges from the edge of the other of the workpieces at the second end such that a second vertex is formed between the edges at the second end; detecting a location of the first and second vertexes using a camera; and moving a laser beam along the interface from the first vertex to the second vertex based on the detected locations of the first and second vertexes to melt a portion of at least one of the steel workpiece and form a weld joint between the steel workpieces.

13. The method of claim 12, wherein said moving comprises moving the laser beam along a linear path from the first vertex to the second vertex.

14. The method of claim 12, wherein: a first notch is formed in at least one of the workpieces at the first end of the interface such that the first vertex is at least partially defined by the first notch, and a second notch is formed in at least one of the workpieces at the second end of the interface such that the second vertex is at least partially defined by the second notch.

15. The method of claim 12, wherein portions of the workpieces at the first end are misaligned with each other, and portions of the workpieces at the second ends are misaligned with each other such that the first vertex is defined where one of the workpieces protrudes past the other of the workpieces, and the second vertex is defined where one of the workpieces protrudes past the other of the workpieces.

16. The method of claim 12, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

17. A method for forming a weld assembly, the method comprising laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld joint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the first workpiece comprises iron and 0.040% < C < 0.100%; the second workpiece comprises iron and 0.10% < C < 0.5%; and the filler wire comprises iron and at least 10% Ni.

18. The method of claim 17, wherein the filler wire comprises: 0.0% < C < 0.03% and 10% < Cr < 40%.

19. The method of claim 18, wherein the filler wire comprises: 18% < Cr < 20%; 11% < Ni < 14%; 2% < Mo < 3%; 1% < Mn < 2.5%; and 0.3% < Si < 0.65%.

20. The method of claim 17, wherein: the filler wire comprises: 0.18%<C<0.25% and 10% < Cr < 40%; and the weld joint comprises 0.15% < C < 0.25%.

21. The method of claim 20, wherein the filler wire comprises: 15%<Cr<17%; 34%<Ni<37%; 0%<Mo<0.75%; l%<Mn<2.5%; and 0%<Cu<0.75%.

22. The method of claim 17, wherein: the first workpiece comprises 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%, and the second workpiece comprises 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%.

23. The method of claim 17, wherein the weld joint comprises ferrite.

24. The method of claim 23, wherein the weld joint comprises less than 5% ferrite.

25. The method of claim 17, wherein a carbon concentration of the weld joint is lower than a carbon concentration of the second workpiece.

26. The method of claim 17, wherein a carbon concentration of the filler wire is lower than a carbon concentration of the second workpiece.

27. The method of claim 17, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

28. A laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein the first workpiece comprises iron and 0.040% < C < 0.100%, wherein the second workpiece comprises iron and 0.10% < C < 0.5%, and wherein a bulk nickel concentration in the weld joint is at least 2.0%.

29. A method for forming a weld assembly, the method comprising laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld joint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the filler wire comprises iron and at least 10% Ni; the weld joint has a ferrite concentration Ferritewr; and0.0% < Ferritewr < 5.0%.

30. The method of claim 29, wherein: the first workpiece comprises iron and 0.040% < C < 0.100%; and the second workpiece comprises iron and 0.10% < C < 0.5%.

31. The method of claim 29, wherein the filler wire comprises: 0.0% < C < 0.03% and 10% < Cr < 40%.

32. The method of claim 31, wherein the filler wire comprises: 18% < Cr < 20%; 11% < Ni < 14%; 2% < Mo < 3%; 1% < Mn < 2.5%; and 0.3% < Si < 0.65%.

33. The method of claim 29, wherein the filler wire comprises: 0.18%<C<0.25% and 10% < Cr < 40%.

34. The method of claim 33, wherein the filler wire comprises: 15% < Cr < 17%; 34% < Ni <37%; 0%< Mo <0.75%; 1%< Mn <2.5%; and 0%< Cu <0.75%.

35. The method of claim 29, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

36. A laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein the weld joint has a ferrite concentration Ferritewr, and wherein 0.0% < Ferritewr < 5.0%.

37. The laser welded assembly of claim 36, wherein an aluminum concentration ALwr in the weld joint is at least 0.5%.

38. A method for forming a weld assembly, the method comprising laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld joint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the filler wire comprises iron and at least 10% Ni; the weld joint has a bulk aluminum concentration of Alwr; and a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10 x ALwr.

39. The method of claim 38, wherein: 0.5% < Alwr < 2.5%.

40. The method of claim 38, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 5 x Alwr.

41. The method of claim 40, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 4 x Alwr.

42. The method of claim 41, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 3 x Alwr.

43. The method of claim 42, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 2 x Alwr.

44. The method of claim 38, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 5%.

45. The method of claim 44, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 4%.

46. The method of claim 45, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 3%.

47. The method of claim 38, wherein a local aluminum concentration within any 0.05 mm x 0.05 mm area within any cross section within the weld joint, as measured using EDX, is less than 5 x Alwr.

48. The method of claim 38, wherein an aluminum concentration within any 0.05 mm x 0.05 mm area within any cross section within the weld joint, as measured using EDX, is less than 5%.

49. The method of claim 38, wherein: the first workpiece comprises iron and 0.040% < C < 0.100%; and the second workpiece comprises iron and 0.10% < C < 0.5%.

50. The method of claim 49, wherein: the first workpiece comprises 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti <0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%, and the second workpiece comprises 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%.

51. The method of claim 38, wherein the filler wire comprises 0-0.03% C, 18-20% Cr, 11-14% Ni, 2-3% Mo, 1-2.5% Mn, and 0.3-0.65% Si.

52. The method of claim 38, wherein the filler wire comprises 0.18-0.25% C, 15.0-17.0% Cr, 0-0.75% Cu, 1.0-2.5% Mn, 0-0.75% Mo, 34.0-37.0% Ni, 0-0.03% P, 0-0.03% S, and 0.30-0.65% Si.

53. The method of claim 38, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

54. A laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein the weld joint has a bulk aluminum concentration of Alwr; and wherein a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10 x ALwr.

55. A method for forming a weld assembly, the method comprising laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld joint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint; the filler wire comprises iron and at least 10% Ni; the weld joint has a bulk aluminum concentration Alwr of less than 2.5%; anda local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10%.

56. The method of claim 55, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 5%.

57. The method of claim 56, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 3%.

58. The method of claim 57, wherein the local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 2.5%.

59. The method of claim 55, wherein: 0.5% < Alwr < 2.5%.

60. The method of claim 55, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

61. A laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein the weld joint has a bulk aluminum concentration of Alwr; and wherein 0.5% < Alwr < 2.5%, and wherein a local aluminum concentration within any 0.1 mm x 0.1 mm area within any cross section within the weld joint, as measured using EDX, is less than 10%.

62. A method for forming a weld assembly, the method comprising laser welding a first steel workpiece to a second steel workpiece using a filler wire to form a weld joint between the first and second steel workpieces, wherein: the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint;the first workpiece comprises iron and 0.040% < C < 0.100%, 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015%< Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr< 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%; the second workpiece comprises iron and 0.10% < C < 0.5%, 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%; the filler wire comprises iron and at least 10% Ni; and the weld joint is such that after hot stamping and cooling, a maximum hardness variation within at least one cross section of the weld joint is greater than 20% of an average hardness of the weld joint within the cross section.

63. The method of claim 62, wherein the maximum hardness variation is greater than 25% of the average hardness.

64. The method of claim 62, wherein the filler wire comprises 10-40% Cr.

65. The method of claim 62, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

66. A laser welded assembly comprising: a first steel workpiece comprising iron and 0.040% < C < 0.100%, 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%; and a second steel workpiece welded to the first steel workpiece along a weld joint, the second workpiece comprising iron and 0.10% < C < 0.5%, 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0%< Mo < 20%, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof,wherein a bulk nickel concentration in the weld joint is at least 2.0%, and wherein the weld joint is such that after hot stamping and cooling, a maximum hardness variation within at least one cross section of the weld joint is greater than 20% of an average hardness of the weld joint within the cross section.

67. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface at a welding speed of between 80 and 120 mm / s to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving at a filler wire feed rate of at least 10 mm3 / s, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint, and wherein the filler wire comprises iron and at least 10% Ni.

68. The method of claim 67, wherein the filler wire comprises 10% < Cr < 40%.

69. The method of claim 67, wherein: the first workpiece comprises iron and 0.040% < C < 0.100%; the second workpiece comprises iron and 0.10% < C < 0.5%; and the filler wire feed rate is between 10 and 40 mm3 / s.

70. The method of claim 69, wherein: the first workpiece comprises 0.80% < Mn < 2.00%, 0.0% < Si < 0.30%, 0.0% < S < 0.005%, 0.0% < P < 0.030%, 0.010% < Al < 0.070%, 0.015% < Nb < 0.100%, 0.0% < Ti < 0.080%, 0.0% < Cu < 0.100%, 0.0% < Ni < 0.100%, 0.0% < Cr < 0.100%, 0.0% < Mo < 0.100%, and 0.0% < Ca < 0.006%, and the second workpiece comprises 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%.

71. The method of claim 67, wherein the first and second workpieces each comprise iron and 0.10% < C < 0.5%, and wherein the filler wire feed rate is between 30 and 65 mm3 / s.

72. The method of claim 71, wherein the first and second steel workpieces each comprise: 0.5% < Mn <3%, 0.1% < Si < 1%, 0.01% < Cr < 1.0%, 0.0% < Ti < 0.2%, 0.0 % < Nb < 0.060%, 0.0% < Al < 0.1%, 0.0% < S < 0.05%, 0.0% < P < 0.1%, 0.0% < B < 0.010%, 0.0% < Cu < 0.2%, 0.0% < Ni < 2%, and 0.0% < Mo < 20%;73. The method of claim 67, wherein a power output of the laser beam is between 4 and 10 kw.

74. The method of claim 67, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

75. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface at a welding speed to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving at a volumetric filler wire feed rate in mm3 / s, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint, wherein the filler wire comprises iron and at least 10% Ni, wherein an average gap width is defined along the interface, wherein a thinner of the workpieces has a thickness t, wherein a welding gap rate in mm3 / s = (average gap width in mm) x (thickness t) x (welding speed in mm / s), and wherein: (volumetric filler wire feed rate) > (welding gap rate).

76. The method of claim 75, wherein the filler wire comprises 10% < Cr < 40%.

77. The method of claim 75, wherein: (volumetric filler wire feed rate) > 1.1 x (welding gap rate).

78. The method of claim 75, wherein the volumetric filler wire feed rate exceeds the welding gap rate by at least 1 mm3 / s.

79. The method of claim 75, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

80. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface at a welding speed to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving at a volumetric filler wire feed rate in mm3 / s, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof such that the laser welding results in aluminum from the coating forming part of the weld joint, wherein the filler wire comprises iron and at least 10% Ni, wherein gap width is defined between the workpieces along the interface, wherein a thinner of the workpieces has a thickness t, wherein an instantaneous welding gap rate in mm3 / s = (gap width in mm at a location of the laser beam along the interface) x (thickness t) x (welding speed in mm / s), and wherein an instantaneous volumetric filler wire feed rate exceeds the instantaneous welding gap rate throughout said moving and feeding.

81. The method of claim 80, wherein the filler wire comprises 10% < Cr < 40%.

82. The method of claim 80, wherein, throughout said moving and feeding: (instantaneous volumetric filler wire feed rate) > 1.1 x (instantaneous welding gap rate).

83. The method of claim 80, wherein throughout said moving and feeding, the instantaneous volumetric filler wire feed rate exceeds the instantaneous welding gap rate by at least 1 mm3 / s.

84. The method of claim 80, further comprising:heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

85. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface to melt a portion of at least one of the steel workpiece to form a melt pool that solidifies to form a weld joint between the steel workpieces; feeding a filler wire into the melt pool at a feed rate during said moving; and varying the feed rate of the filler wire during said moving.

86. The method of claim 85, further comprising detecting a size of a gap between the workpieces at multiple locations along the interface, wherein said varying of the feed rate comprises varying the feed rate based on variations in the detected gap.

87. The method of claim 85, further comprising detecting a size of a gap between the workpieces at multiple locations along the interface, wherein said varying comprises increasing the feed rate where the gap widens and reducing the feed rate where the gap narrows.

88. The method of claim 85, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

89. A method for laser welding a first steel workpiece to a second steel workpiece to form a weld assembly, the method comprising: arranging the first and second workpieces relative to each other such that an interface is formed between the first and second workpieces; moving a laser beam along the interface to melt a portion of at least one of the steel workpieces to form a melt pool that solidifies to form a weld joint between the steel workpieces; and feeding a filler wire into the melt pool during said moving,wherein, in a cross-section perpendicular to the weld joint, the weld joint has a top surface overfill OTOP or a bottom surface overfill OBOTTOM, wherein a thinner of the steel workpieces has a thickness t, and wherein at least one of OTOP and OBOTTOM is equal to or greater than O.lt.

90. The method of claim 89, wherein: O.lt < OTOP.

91. The method of claim 89, wherein at least one of OTOP and OBOTTOM is equal to or greater than 0.15t.

92. The method of claim 89, further comprising stamping the weld assembly between first and second dies, wherein at least one of the dies includes a recess to accommodate an overfill of the weld joint.

93. The method of claim 89, wherein: 0.15t < (OTOP + OBOTTOM).

94. The method of claim 93, wherein 0.20t < (OTOP + OBOTTOM).

95. The method of claim 94, wherein 0.25t < (OTOP + OBOTTOM).

96. The method of claim 89, further comprising: heating the weld assembly to a temperature above an AC3 temperature of both workpieces; hot-stamping the weld assembly to form a hot-stamped part; and quenching at least a portion of the hot-stamped part.

97. A laser welded assembly comprising: a first steel workpiece; and a second steel workpiece welded to the first steel workpiece along a weld joint, wherein the first and second steel workpieces each have a coating comprising aluminum on at least one surface thereof, wherein a bulk nickel concentration in the weld joint is at least 2.0%, wherein, in a cross-section perpendicular to the weld joint, the weld joint has a top surface overfill OTOP or a bottom surface overfill OBOTTOM, wherein a thinner of the steel workpieces has a thickness t, and wherein at least one of OTOP and OBOTTOM is equal to or greater than O.lt.

98. The laser welded assembly of claim 97, wherein: 0.15t < (OTOP + OBOTTOM).

99. The laser welded assembly of claim 98, wherein: 0.2t < (OTOP + OBOTTOM).

100. The laser welded assembly of claim 99, wherein: 0.25t < (OTOP + OBOTTOM).

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