Ultra-hard cold-work steel alloy

Abstract

Embodiments relate to cold worked steel alloys having improved strength, hardness and corrosion resistance that are useful for making products such as exterior vehicle body components. A process for preparing the cold worked steel alloys is also described.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] Any application for which a foreign or domestic priority claim is identified in the Application Data Sheet filed with this application is incorporated herein by reference under 37 CFR 1.57 and Rules 4.18 and 20.6. This application claims priority to U.S. Provisional Application No. 63 / 234,016, entitled "ULTRA-HARD COLD-WORKED STEEL ALLOY," filed August 17, 2021, which is incorporated herein by reference in its entirety.

[0002] The present invention relates to steel alloys, more particularly to steel alloys with improved hardness and corrosion resistance for high performance applications, including automotive components. [Background technology]

[0003] [Description of Related Art] There are many "stainless" steels that resist corrosion, including the commercially available "3xx" series family of stainless steel alloys. The most common of these alloys are 301, 304 / 304L, and 316 / 316L, which are commonly manufactured in a variety of product forms. There are also other stainless steel products that are differentiated based on their microstructure and method of strength: austenitic (3xx series), martensitic (4xx series), ferritic, duplex, and precipitation hardenable (PH).

[0004] To increase hardness, martensitic steels generally require controlled heat treatment and quench cycles, sometimes including cryogenic treatment, to ensure complete martensitic transformation and hardening of the alloy. However, the addition of such treatments increases alloy costs, heat treatment requires expensive equipment, and depending on the product form, may cause warping of the target product. Additionally, corrosion-resistant martensitic steels typically incorporate relatively large amounts of cobalt for corrosion resistance. However, cobalt is an expensive material that increases the cost of using martensitic alloys. Summary of the Invention

[0005] For purposes of summarizing the disclosure and the advantages achieved over the prior art, certain objects and advantages of the disclosure are described herein. Not all such objects or advantages may be achieved in any particular embodiment. Thus, for example, one skilled in the art will recognize that the invention may be embodied or implemented to achieve or optimize one advantage or advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0006] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, although the invention is not limited to any particular preferred embodiment(s) disclosed.

[0007] In one embodiment, a steel alloy composition is described. The composition comprises Fe, has a hardness of at least about 400 HV, and has an E pit -E ocp The corrosion resistance is at least about 500 mV.

[0008] In some embodiments, the hardness is from about 420HV to about 500HV. pit -E ocp The corrosion resistance is from about 520 mV to about 800 mV. pit -E ocpThe corrosion resistance is from about 520 mV to about 600 mV. In some embodiments, the composition has a yield strength of at least about 1100 MPa. In some embodiments, the composition has a ductility of at least about 60° bend angle at a thickness of 1.8 mm. In some embodiments, martensite formation begins at about 260 K to about 340 K. In some embodiments, martensite formation begins at about 260 K to about 320 K. In some embodiments, the composition has at least about 12 volume percent martensite. In some embodiments, the composition has a yield strength of at least about 1100 MPa.

[0009] In some embodiments, the composition comprises: Cr: 15~18% by weight, Ni: 4~8% by weight, Mn: 1.5~6% by weight, Contains Fe:Bal.

[0010] In some embodiments, the composition further comprises up to about 0.25 wt% N. In some embodiments, the composition further comprises up to about 2 wt% Mo. In some embodiments, the composition comprises up to about 0.03 wt% C, up to about 0.75 wt% Si, up to about 0.045 wt% P, and up to about 0.03 wt% S.

[0011] In some embodiments, the composition comprises: C: up to about 0.03% by weight, N: 0.05~0.25% by weight, Cr: 15~18% by weight, Ni: 4~8% by weight, Mn: 1.5~6% by weight, Si: up to about 0.75% by weight, Mo: 0.5~2% by weight, P: up to about 0.045% by weight; S: up to about 0.03% by weight, and Contains Fe:Bal.

[0012] In some embodiments, the composition comprises: Cu: up to about 0.5% by weight, Co: up to about 0.8% by weight Al: up to about 0.03% by weight, Ti: up to about 0.03 wt.%, and B: Contains a maximum of about 0.05% by weight.

[0013] In some embodiments, the composition further comprises up to about 0.05 wt.% each of at least one additional element, the at least one additional element being up to about 0.15 wt.% in total.

[0014] In another aspect, a process for preparing an alloy is described, the process comprising: casting a steel alloy including Fe, subjecting the steel alloy to a treatment step selected from the group consisting of hot working, annealing, pickling, and combinations thereof to form a treated steel alloy, and cold working the treated steel alloy to have a hardness of at least about 400 HV and an E of at least about 500 mV in a 3 wt. % aqueous sodium chloride solution. pit -E ocp forming a cold worked steel alloy having corrosion resistance.

[0015] In some embodiments, the treated steel alloy is cold worked to a thickness reduction of at least about 30%. In some embodiments, the cold worked steel has a thickness of about 0.01 mm to about 4 mm. In some embodiments, the cold worked steel has a thickness of about 1 mm to about 4 mm. In some embodiments, the process further comprises machining the cold worked steel. In some embodiments, the hot working occurs prior to annealing the steel alloy. In some embodiments, the annealing occurs prior to hot working the steel alloy. In some embodiments, the treatment of the steel alloy occurs prior to cold working the treated steel alloy.

[0016] In another aspect, a vehicle is described that includes a vehicle body that includes a steel alloy composition. In some embodiments, the vehicle body includes an exterior vehicle body, and the exterior vehicle body includes a steel alloy. In some embodiments, the steel alloy is uncoated. In some embodiments, no corrosion protection agent is disposed on the steel alloy. In some embodiments, the corrosion protection agent is a paint. In some embodiments, the vehicle is an electric vehicle that includes an electric motor. [Brief description of the drawings]

[0017] [Figure 1A] The calculation results of the corrosion resistance of steel alloys in terms of pitting resistance index (PREN) versus martensite formation start temperature (Ms) are shown.

[0018] [Figure 1B] The calculation results of the steel alloys for the driving force comparison between FCC, BCC and HCP are shown.

[0019] [Figure 2A] Calculation results of the corrosion resistance in terms of pitting resistance index (PREN) versus martensite formation start temperature (Ms) for steel alloys A4, A7 and A8 are shown.

[0020] [Figure 2B] The calculation results of steel alloys A4, A7 and A8 for driving force comparison among FCC, BCC and HCP are shown.

[0021] [Figure 2C] The calculation results of the corrosion resistance in terms of pitting resistance index (PREN) versus martensite formation start temperature (Ms) for alloys 1 to 7 are shown.

[0022] [Diagram 3] 1 shows an Ashby Plot of calculated hardness versus corrosion resistance for steel alloys A4, A7 and A8 plotted against the actual respective values ​​for commercially available steel alloys.

[0023] [Figure 4A]1 shows an optical micrograph of A4 alloy prepared by cold working to a 24% reduction on a 50 lb scale. [Figure 4B] 1 shows an optical micrograph of A4 alloy prepared by cold working to a 24% reduction on a 50 lb scale.

[0024] [Figure 5A] 1 shows an optical micrograph of A4 alloy prepared by cold working to a 36% reduction on a 50 lb scale. [Figure 5B] 1 shows an optical micrograph of A4 alloy prepared by cold working to a 36% reduction on a 50 lb scale.

[0025] [Figure 6A] 1 shows an optical micrograph of A4 alloy prepared by cold working to 44% reduction at 50 lb scale. [Figure 6B] 1 shows an optical micrograph of A4 alloy prepared by cold working to 44% reduction at 50 lb scale.

[0026] [Figure 7A] 1 shows an optical micrograph of A4 alloy prepared by cold working to a 56% reduction on a 50 lb scale. [Figure 7B] 1 shows an optical micrograph of A4 alloy prepared by cold working to a 56% reduction on a 50 lb scale.

[0027] [Figure 8] 1 shows the experimentally measured hardness, strength and elongation properties of A4, A7 and A8 alloys prepared at 50 kg scale.

[0028] [Figure 9] FIG. 1 shows longitudinal stress-strain experimental data for 50 kg scale prepared A4 alloy cold worked to various degrees.

[0029] [Figure 10] FIG. 1 shows longitudinal stress-strain experimental data for 50 kg scale prepared A7 alloy cold worked to various degrees.

[0030] [Figure 11] FIG. 1 shows longitudinal stress-strain experimental data for 50 kg scale prepared A8 alloy cold worked to various degrees.

[0031] [Figure 12A] FIG. 1 shows an optical micrograph of cold worked A4 alloy prepared on a 50 kg scale.

[0032] [Figure 12B] FIG. 1 shows an optical micrograph of cold worked A7 alloy prepared on a 50 kg scale.

[0033] [Figure 12C] FIG. 1 shows an optical micrograph of cold worked A8 alloy prepared on a 50 kg scale.

[0034] [Figure 13A] The experimental results of Epit-Eocp corrosion resistance of A4 alloy and A7 alloy are shown.

[0035] [Figure 13B] The experimental results of the corrosion current density Icorr of the A4 alloy and the A7 alloy are shown.

[0036] [Figure 14A] The experimental results of Epit-Eocp corrosion resistance of A4, A7, B1, B2 and B3 are shown.

[0037] [Figure 14B] The experimental results of the corrosion current density Icorr of the A4, A7, B1, B2 and B3 alloys are shown.

[0038] [Figure 15A] The experimental results of Epit-Eocp corrosion resistance of A4, A7, B1, B2 and B3 alloys against corrosion resistance in Pitting Resistance Index (PREN) are shown.

[0039] [Figure 15B]The experimental results of corrosion current density Icorr for A4, A7, B1, B2 and B3 alloys versus corrosion resistance with pitting resistance index (PREN) are shown.

[0040] [Figure 16A] The experimental results of Epit-Eocp corrosion resistance of Alloy 1, Alloy 2 and Alloy 4 are shown.

[0041] [Figure 16B] The experimental results of the corrosion current density Icorr of Alloy 1, Alloy 2, and Alloy 4 are shown.

[0042] [Figure 17] FIG. 1 shows experimental results of longitudinal and transverse bend angles for Alloy 1 compared to Type 301 stainless steel.

[0043] [Figure 18] The stress-strain experimental data of A4 alloy is shown. Detailed Description of the Invention

[0044] The present disclosure may be understood by reference to the following detailed description: It should be noted that for clarity of illustration, certain elements in the various drawings may not be drawn to scale and may be represented diagrammatically or conceptually and may not otherwise precisely correspond to particular physical configurations of the embodiments.

[0045] Embodiments relate to "cold worked" (e.g., cold rolled) steel alloys with improved strength, hardness, and corrosion resistance useful for making products such as exterior vehicle body components. Such cold worked steel alloys may enable exterior vehicle body components to resist dents, scratches, and pitting while avoiding the need for corrosion protectants (e.g., paints) on the exterior vehicle body components. Cold working (e.g., cold rolling) strengthens the disclosed steel alloys due in part to strain-induced martensitic phase transformation of the austenitic matrix, which imparts improved hardness and strength for scratch and dent resistance. Advantageously, it has been found that the phase transformation of the disclosed steel alloys increases hardness and strength while maintaining corrosion resistance.

[0046] One embodiment has a hardness of at least about 400 HV and an E in a 3 wt. % aqueous sodium chloride solution. pit -E ocp In some embodiments, the cold worked steel alloy has a yield strength of at least about 1150 MPa, a hardness of at least about 420 HV or 43 HRC, a bend angle of at least about 60° at 1.8 mm thickness, and an E in 3 wt % aqueous sodium chloride solution of at least about 500 mV. pit -E ocp In some embodiments, the cold worked steel alloy has a yield strength of at least about 1100 MPa, a hardness of at least about 420 HV or 43 HRC, a bend angle of at least about 60° at 1.6 mm thickness, and an E in 3 wt. % aqueous sodium chloride solution of at least about 520 mV. pit -E ocp In some embodiments, the cold worked steel alloy has a yield strength of about 1200 MPa, a hardness of at least about 45 HRC, a bend angle of at least about 65° at 1.8 mm thickness, and an E in 3 wt % aqueous sodium chloride solution of at least about 530 mV. pit -E ocp It is corrosion resistant.

[0047] Another embodiment has a hardness of at least about 400 HV and an E in a 3 wt. % aqueous sodium chloride solution. pit -E ocp In some embodiments, the cold worked steel alloy has a yield strength of at least about 1100 MPa, a hardness of at least about 420 HV or 43 HRC, a bend angle of at least about 60° at 1.6 mm thickness, and an E in 3 wt % aqueous sodium chloride solution of at least about 520 mV. pit -E ocp In some embodiments, the cold worked steel alloy has a yield strength of about 1200 MPa, a hardness of at least about 45 HRC, a bend angle of at least about 65° at 1.8 mm thickness, and an E in 3 wt % aqueous sodium chloride solution of at least about 530 mV. pit -Eocp It is corrosion resistant.

[0048] ·Steel alloy composition The steel alloys disclosed herein have been found to have improved hardness and corrosion resistance when cold worked. In some embodiments, the steel alloy is a stainless steel alloy. The steel alloys are described herein by the weight percentage (wt%) of all elements and particles within the alloy, as well as certain properties of the alloy. It will be understood that the remaining composition of any alloy described herein includes iron (Fe) and incidental impurities.

[0049] Impurities may be present in the starting material or may be introduced during one of the processing and / or manufacturing steps to make the steel alloy. Incidental impurities are compounds and / or elements that do not affect or do not substantially affect the material properties of the composition, such as hardness, corrosion resistance, yield strength, tensile strength, ductility, martensite formation and / or ferrite formation. In some embodiments, the total of incidental impurities or other elements is, is about, is up to, is up to, is up to about, is 1%, 0.8%, 0.5%, 0.2%, 0.15%, 0.1%, 0.05%, or 0.01% by weight, or any range of values ​​therebetween. In some embodiments, each unlisted incidental impurity or each additional element is, is about, is up to, or is up to about 0.8%, 0.5%, 0.2%, 0.1%, 0.05%, 0.01%, 0.005%, or 0.001% by weight, or any range of values ​​therebetween.

[0050] In some embodiments, the steel alloy includes at least partially incorporation of nitrogen for corrosion resistance and hardenability properties. In some embodiments, the steel alloy includes at least partially chromium for corrosion resistance and strain induced martensite transition properties. In some embodiments, the steel alloy includes at least partially nickel for toughness and tailored austenite stability. In some embodiments, the steel alloy includes at least partially manganese for austenite stability, cost effectiveness and stacking fault energy tailoring properties. In some embodiments, the steel alloy includes at least partially molybdenum for corrosion resistance and hardenability properties and to allow for a low carbon content for enhanced corrosion resistance.

[0051] In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.05-0.25 wt.% N, at or about 15-18 wt.% Cr, at or about 4-8 wt.% Ni, at or about 1.5-6 wt.% Mn, at or about 0.75 wt.% Si, at or about 0.5-2 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.15-0.25 wt.% N, at or about 16-18 wt.% Cr, at or about 5-6 wt.% Ni, at or about 1.5-2.5 wt.% Mn, at or about 0.75 wt.% Si, at or about 1-2 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.15-0.25 wt.% N, at or about 16-18 wt.% Cr, at or about 5-6 wt.% Ni, at or about 1.5-3.0 wt.% Mn, at or about 0.75 wt.% Si, at or about 1-2 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities.In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.05-0.15 wt.% N, at or about 15-17 wt.% Cr, at or about 6-8 wt.% Ni, at or about 1.5-2.5 wt.% Mn, at or about 0.75 wt.% Si, at or about 0.5-1.5 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.05-0.15 wt.% N, at or about 15-17 wt.% Cr, at or about 4-6 wt.% Ni, at or about 4-6 wt.% Mn, at or about 0.75 wt.% Si, at or about 0.75-1.5 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.11 wt.% N, at or about 16 wt.% Cr, at or about 6 wt.% Ni, at or about 2 wt.% Mn, at or about 0.75 wt.% Si, at or about 1.2 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities.In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.12 wt.% N, at or about 13 wt.% Cr, at or about 4 wt.% Ni, at or about 6 wt.% Mn, at or about 0.75 wt.% Si, at or about 2 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder of the composition (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.05-0.15 wt.% N, at or about 10-15 wt.% Cr, at or about 3.5-4.5 wt.% Ni, at or about 4-6 wt.% Mn, at or about 0.75 wt.% Si, at or about 1.5-2.5 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.1 wt.% N, at or about 11 wt.% Cr, at or about 4 wt.% Ni, at or about 6 wt.% Mn, at or about 0.75 wt.% Si, at or about 1.0 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder of the composition (by weight) being Fe and incidental impurities.In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt.% C, at or about 0.05-0.15 wt.% N, at or about 10-15 wt.% Cr, at or about 3.5-4.5 wt.% Ni, at or about 4-6 wt.% Mn, at or about 0.75 wt.% Si, at or about 0.5-1.5 wt.% Mo, at or about 0.045 wt.% P, at or about 0.03 wt.% S, with the remainder (by weight) being Fe and incidental impurities. In some embodiments, the steel alloy composition comprises at most or at most about 0.03 wt% C, at or about 0.15 wt% N, at or about 16 wt% Cr, at or about 5.5 wt% Ni, at or about 2.7 wt% Mn, at or about 0.75 wt% Si, at or about 1.25 wt% Mo, at or about 0.045 wt% P, at or about 0.03 wt% S, with the remaining composition (by weight) being Fe and incidental impurities. In some embodiments, the maximum incidental impurities or other elements are total, about total, up to total, or up to about 0.15 or 0.1 wt% total. In some embodiments, the amount of incidental impurities of each element or each other element is 0.05% by weight, about 0.05% by weight, at most 0.05% by weight, or at most about 0.05% by weight.

[0052] In some embodiments, the steel alloy composition comprises carbon (C) in an amount of about, at least, at least about, up to, or up to about 0.1%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, or 0.005% by weight, or any range of values ​​therebetween. In some embodiments, the steel alloy composition comprises nitrogen (N) in an amount of about, at least, at least about, up to, or up to about 1%, 0.5%, 0.25%, 0.2%, 0.15%, 0.12%, 0.11%, 0.1%, 0.05%, or 0.01% by weight, or any range of values ​​therebetween. In some embodiments, the steel alloy composition comprises chromium (Cr) in an amount of about, at least, at least about, up to, or up to about 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, or 10% by weight, or any range of values ​​therebetween. In some embodiments, the steel alloy composition comprises nickel (N) in an amount of about, at least, at least about, up to, or up to about 15%, 10%, 9%, 8%, 7%, 6%, 5.5%, 5%, 4%, 3%, 2%, 1%, or 0.5% by weight, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes manganese (Mn) in an amount of 15 wt.%, 10 wt.%, 9 wt.%, 8 wt.%, 7 wt.%, 6 wt.%, 5 wt.%, 4 wt.%, 3 wt.%, 2.7 wt.%, 2.5 wt.%, 2 wt.%, 1.5 wt.%, 1 wt.%, 0.5 wt.%, or 0.1 wt.%, about that amount, at least that amount, at least that amount, up to that amount, or up to that amount, or any range of values ​​therebetween.In some embodiments, the steel alloy composition comprises silicon (Si) in an amount of 2 wt.%, 1 wt.%, 0.9 wt.%, 0.8 wt.%, 0.75 wt.%, 0.7 wt.%, 0.65 wt.%, 0.6 wt.%, 0.55 wt.%, 0.5 wt.%, 0.4 wt.%, 0.3 wt.%, 0.2 wt.%, 0.1 wt.%, or 0.05 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes molybdenum (Mo) in an amount of 5 wt.%, 4 wt.%, 3 wt.%, 2 wt.%, 1.7 wt.%, 1.5 wt.%, 1.4 wt.%, 1.25 wt.%, 1.2 wt.%, 1 wt.%, 0.9 wt.%, 0.8 wt.%, 0.75 wt.%, 0.7 wt.%, 0.6 wt.%, 0.5 wt.%, 0.4 wt.%, 0.3 wt. 0.2 wt.%, 0.1 wt.%, or 0.05 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween. In some embodiments, the steel alloy composition comprises phosphorus (P) in an amount of 1 wt.%, 0.5 wt.%, 0.1 wt.%, 0.08 wt.%, 0.07 wt.%, 0.06 wt.%, 0.05 wt.%, 0.045 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes sulfur (S) in an amount of 1 wt.%, 0.5 wt.%, 0.1 wt.%, 0.08 wt.%, 0.07 wt.%, 0.06 wt.%, 0.05 wt.%, 0.045 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween.In some embodiments, the steel alloy composition includes copper (Cu) in an amount of 2 wt.%, 1 wt.%, 0.9 wt.%, 0.8 wt.%, 0.7 wt.%, 0.6 wt.%, 0.5 wt.%, 0.4 wt.%, 0.3 wt.%, 0.2 wt.%, 0.1 wt.%, 0.08 wt.%, 0.07 wt.%, 0.06 wt.%, 0.05 wt.%, 0.045 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes cobalt (Co) in an amount of, about, at least, at least about, up to, or up to about 2 wt.%, 1 wt.%, 0.9 wt.%, 0.8 wt.%, 0.7 wt.%, 0.6 wt.%, 0.5 wt.%, 0.4 wt.%, 0.3 wt.%, 0.2 wt.%, 0.1 wt.%, 0.08 wt.%, 0.07 wt.%, 0.06 wt.%, 0.05 wt.%, 0.045 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes aluminum (Al) in an amount of 1 wt.%, 0.5 wt.%, 0.1 wt.%, 0.08 wt.%, 0.07 wt.%, 0.06 wt.%, 0.05 wt.%, 0.045 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes titanium (Ti) in an amount of 1 wt.%, 0.5 wt.%, 0.1 wt.%, 0.08 wt.%, 0.07 wt.%, 0.06 wt.%, 0.05 wt.%, 0.045 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, about that amount, at least that amount, at least about that amount, up to that amount, or up to about that amount, or any range of values ​​therebetween.In some embodiments, the steel alloy composition includes boron (B) in an amount of about, at least about, up to, or up to about 1%, 0.5%, 0.1%, 0.08%, 0.07%, 0.06%, 0.05%, 0.045%, 0.04%, 0.03%, 0.02%, 0.01%, or 0.005% by weight, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes incidental impurities or additional elements not listed in an amount of about, at least about, up to, or up to about 0.1%, 0.07%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, or 0.005% by weight, or any range of values ​​therebetween. In some embodiments, the steel alloy composition includes a maximum of incidental impurities or additional elements in a total amount of, about, up to, or up to about 1 wt.%, 0.5 wt.%, 0.3 wt.%, 0.2 wt.%, 0.15 wt.%, 0.1 wt.%, 0.07 wt.%, 0.05 wt.%, 0.04 wt.%, 0.03 wt.%, 0.02 wt.%, 0.01 wt.%, or 0.005 wt.%, or any range of values ​​therebetween.

[0053] In some embodiments, the steel alloy composition comprises martensite in an amount of about, at least, at least about, up to, or up to about 50%, 40%, 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 8%, or 5% by volume, or any range of values ​​therebetween. In some embodiments, the steel alloy composition comprises ferrite in an amount of about, at least, at least about, up to, or up to about 50%, 40%, 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 8%, or 5% by volume, or any range of values ​​therebetween.

[0054] A computational search space for steel alloys with wt. % Fe-Cr-Ni-Mo-Mn-CN-0.75Si was performed and is shown in Figures 1A and 1B, where Figure 1A shows the computational results for corrosion resistance in terms of pitting resistance index (PREN) versus martensite formation start temperature (Ms) and Figure 1B shows the computational results for driving force comparison between FCC, BCC and HCP. Using the computational search space, the steel alloy composition ranges along with predicted martensite formation temperature ranges and pitting resistance index (PREN) are shown in Table 1 below for steel alloys A1 to A8. [Table 1]

[0055] 2A and 2B show the calculation results of the pitting resistance index (PREN) versus the martensite formation start temperature (Ms) for alloys A4, A7, and A8, respectively, and the driving force comparison between FCC, BCC, and HCP. FIG. 2C shows the calculation results of the pitting resistance index (PREN) versus the martensite formation start temperature (Ms) for A4 (i.e., alloy 1), A7 (i.e., alloy 2), A8 (i.e., alloy 3), B1 (i.e., alloy 4), B2 (i.e., alloy 5), B3 (i.e., alloy 6), and A4(2) (i.e., alloy 7), respectively. The steel alloy composition ranges for alloy A4 (i.e., alloy 1), A7 (i.e., alloy 2), A8 (i.e., alloy 3), B1 (i.e., alloy 4), B2 (i.e., alloy 5), B2(2), B3 (i.e., alloy 6), B3(2), A4(2) (i.e., alloy 7) and A4(3) are shown in Table 2 below. [Table 2]

[0056] Figure 3 shows an Ashby Plot of the calculated hardness versus corrosion resistance of steel alloys A4, A7 and A8 plotted against the actual respective values ​​of the commercial steel alloys. As shown in Figure 3, alloys A4, A7 and A8 are calculated to approach or exceed the hardness of 420HV and the corrosion resistance of the 304L / 316L commercial alloys.

[0057] ·Crystallization of steel alloys In some embodiments, the steel alloy is an austenitic steel in the O-temper annealed condition. Work hardening can result in the formation of strain-induced martensite. The extent to which strain-induced martensite forms can be attributed to the austenitic stability of the alloy at the conditions of cold work, including temperature and pressure. In some embodiments, as more strain-induced martensite forms, the alloy becomes harder, ferromagnetic properties increase, corrosion resistance is improved, and / or the strength of the material can be improved.

[0058] In some embodiments, the steel alloy forms a martensitic crystal structure at about, at least, at least about, up to, or up to about 500K, 450K, 400K, 350K, 340K, 330K, 320K, 310K, 300K, 290K, 289K, 280K, 270K, 260K, 250K, 240K, 220K, 200K, or 150K, or at any range of values ​​therebetween.

[0059] ·Alloy hardness The hardness of the alloy may be controlled to provide scratch resistance and to maintain a particular level of pitting and environmental resistance to the alloy. The hardness of the alloy may be given and / or calculated according to a variety of scales. In some embodiments, the hardness is given on the Rockwell scale (e.g., HRC). In some embodiments, the hardness is given on the Vickers scale (i.e., HV).

[0060] In some embodiments, the steel alloy has a hardness of about, at least, at least about, at most about, or at most about 35HRC, 40HRC, 41HRC, 42HRC, 43HRC, 44HRC, 45HRC, 46HRC, 47HRC, 48HRC, 49HRC, 50HRC, 52HRC, 55HRC, or 60HRC, or any range of values ​​therebetween. In some embodiments, the steel alloy has a hardness of about, at least, at least about, at most about, or at most about 350HV, 370HV, 375HV, 380HV, 390HV, 400HV, 410HV, 420HV, 430HV, 450HV, 475HV, or 500HV, or any range of values ​​therebetween.

[0061] Corrosion resistance / oxidation resistance Cold worked steel alloys are expected to survive in harsh environments such as those used in automotive applications where automotive vehicles are exposed to extreme high and low temperature environments. In some embodiments, the steel alloys are corrosion and / or oxidation resistant, improving environmental and / or dissolution resistance. The corrosion resistance of the alloys may be given according to various scales and / or relative to other known alloys. In some embodiments, the corrosion resistance is given on the Pitting Resistance Index (PREN) scale. In some embodiments, the corrosion resistance is given according to the Critical Pitting Potential (E pit ) and open circuit potential (E ocp ) In some embodiments, the pitting potential is measured versus a saturated calomel electrode (SCE).

[0062] In some embodiments, the corrosion resistance of the steel alloy is equal to, approximately equal to, at least equal to, or at least approximately equal to, 304L or 316L alloys. In some embodiments, the corrosion resistance of the steel alloy is, about, at least about, or any range of values ​​therebetween of 15PREN, 18PREN, 20PREN, 21PREN, 22PREN, 23PREN, 24PREN, 25PREN, 26PREN, 27PREN, 28PREN, 29PREN, 30PREN, 32PREN, 35PREN, or 40PREN. In some embodiments, the E of the steel alloy in a 3 wt. % aqueous sodium chloride solution is equal to, about, at least about, or any range of values ​​therebetween. pit -E ocp The corrosion resistance is, about, at least about, or any range of values ​​therebetween, 450mV vs. SCE, 480mV vs. SCE, 490mV vs. SCE, 500mV vs. SCE, 510mV vs. SCE, 520mV vs. SCE, 530mV vs. SCE, 540mV vs. SCE, 550mV vs. SCE, 560mV vs. SCE, 570mV vs. SCE, 580mV vs. SCE, 590mV vs. SCE, 600mV vs. SCE, 620mV vs. SCE, 650mV vs. SCE, 700mV vs. SCE, 750mV vs. SCE, 800mV vs. SCE, or 850mV vs. SCE. In some embodiments, the corrosion current density of the steel alloy in a 3 wt. % sodium chloride solution is greater than or equal to 10nA / cm. 2 , 15nA / cm 2 , 20nA / cm 2 , 25nA / cm 2 , 30nA / cm 2 , 35nA / cm 2 , 40nA / cm 2 , 45nA / cm 2 , 50nA / cm 2 , 55nA / cm 2 , 60nA / cm 2 , 65nA / cm 2 or 70nA / cm 2or is about that value, or is at least that value, or is at least about that value, or any range of values ​​therebetween.

[0063] ·Alloy yield strength The steel alloy may have improved yield strength, which may improve dent and scratch resistance.

[0064] In some embodiments, the yield strength of the steel alloy is, or is at least, or is at least about, 900 MPa, 1000 MPa, 1050 MPa, 1100 MPa, 1150 MPa, 1200 MPa, 1250 MPa, 1300 MPa, 1450 MPa, 1500 MPa, 1600 MPa, 1700 MPa, 1800 MPa, 2000 MPa, or 2500 MPa, or any range of values ​​therebetween.

[0065] Ultimate tensile strength of alloy In some embodiments, the ultimate tensile strength of the steel alloy is, is about, is at least, or is at least about 800 MPa, 900 MPa, 1000 MPa, 1050 MPa, 1100 MPa, 1150 MPa, 1200 MPa, 1250 MPa, 1300 MPa, 1450 MPa, 1500 MPa, 1600 MPa, 1700 MPa, 1800 MPa, 2000 MPa, or 2500 MPa, or any range of values ​​therebetween.

[0066] Alloy ductility The ductility of a steel alloy may also be considered so that the part is suitable for use in automotive applications. The ductility of an alloy can be measured by the bend angle and / or the elongation of the alloy, with the bend angle being preferred.

[0067] In some embodiments, the bend angle of the alloy is, about, at least, at least about, at most about, at least about, at 40°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 110°, 120°, 130°, 140°, or 160°, or is, about, at least, at most about, at most about, or at any range of values ​​therebetween. In some embodiments, the bend angle is measured at a section thickness of 1.0 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, or 4 mm, about, at most, at most about, at least, at most about, or at any range of values ​​therebetween. In some embodiments, the bend angle is measured using the VDA238-100 evaluation criteria. In some embodiments, the longitudinal bend angle is measured. In some embodiments, the longitudinal bend angle is the bend angle measured in a direction parallel to the rolling direction, while in some embodiments, the transverse bend angle is measured in a direction perpendicular to the rolling direction. Treatment Method

[0068] Embodiments of the present disclosure include processes for preparing cold worked steel alloys. The steel alloys are cold worked to improve alloy properties such as hardness, strength and / or corrosion resistance. In some embodiments, the cold working improves additional alloy properties such as crystallographic properties, yield strength, ultimate tensile strength and / or ductility. In some embodiments, the cold working is configured to achieve or maintain ductility for the steel alloy prior to cold working. In some embodiments, the cold working may be performed by cold rolling the alloy.

[0069] In some embodiments, the process further comprises casting the alloy of the elemental composition described herein. In some embodiments, the process further comprises hot working (e.g., hot rolling and / or hot drawing), annealing and / or pickling the alloy. In some embodiments, the process further comprises hot working (e.g., hot rolling and / or hot drawing), annealing and / or pickling the alloy prior to cold working (e.g., cold rolling and / or cold drawing) the alloy. In some embodiments, the hot working of the alloy occurs before annealing and / or pickling the alloy. In some embodiments, the hot working of the alloy occurs after annealing and / or pickling the alloy.

[0070] In some embodiments, the process further comprises cutting and / or machining the steel alloy and / or the cold worked steel alloy. In some embodiments, the steel alloy is a monolithic metal sheet. In some embodiments, the monolithic metal sheet may be produced by providing an initial monolithic metal sheet, cutting the initial monolithic metal sheet to form a cut monolithic metal sheet, and shaping the cut monolithic metal sheet to form the monolithic metal sheet. In some embodiments, the monolithic metal sheet is in the shape of a door panel. In some embodiments, the monolithic metal sheet is in the shape of an exterior of a frame. In some embodiments, the cutting is performed by laser cutting.

[0071] In some embodiments, the alloy is cold worked to a thickness reduction (i.e., % cold work=100*([initial thickness]-[cold worked thickness]) / [initial thickness]) of 20%, 25%, 30%, 35%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 55%, 60%, 65%, 70%, 75%, or 80%, about, at least, at least about, up to, or up to about, the thickness before cold working, or any range of values ​​therebetween. In some embodiments, the alloy is cold worked to a thickness of, about, at, or up to about 0.01 mm, 0.05 mm, 0.1 mm, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, 10 mm. In some embodiments, the cold worked steel alloy is in a form selected from sheet, plate, wire, bar, or combinations thereof, In some embodiments, the treatment of the steel alloy is performed prior to cold working the treated steel alloy.

[0072] ·vehicle Embodiments of the present disclosure include vehicles comprising the disclosed steel alloys. In some embodiments, at least one exterior panel and / or body of the vehicle comprises the steel alloy. In some embodiments, the vehicle architecture is designed such that the exterior panels of the vehicle also contribute to the structural performance of the vehicle, and such exterior panels of the vehicle may be referred to as "exoskeletons." In some embodiments, the exterior panels are or are formed from monolithic metal sheets of the steel alloy. In some embodiments, the corrosion resistance of the monolithic metal sheets allows for the utilization of the exterior panels of the vehicle without the application of anti-corrosion coatings or corrosion protection agents (e.g., paints). In some embodiments, the exterior surface of the exterior panels does not include paint.

[0073] In some embodiments, the vehicle is an automotive vehicle. In some embodiments, the vehicle comprises an electric motor. In some embodiments, the automotive vehicle is a truck or a car (e.g., a sedan). In some embodiments, the exterior panel is selected from the group consisting of a door panel, a roof panel, a bottom panel, a hood panel, a fender panel, a trunk panel, a liftgate panel, and combinations thereof. In some embodiments, the exterior panel is a door panel.

[0074] Also disclosed are methods of manufacturing a vehicle, such as an automotive vehicle, in some embodiments, a monolithic metal sheet is provided, at least one component is attached directly to the monolithic metal sheet to form an exterior panel, and the exterior panel is attached to the exterior of a vehicle body. EXAMPLES

[0075] Example 1 - 50lb scale Alloys within the target range of Alloy A4 were prepared on a 50 lb scale with the actual compositional alloying element values ​​shown in Table 3. The alloys were formed by casting the alloy, then machining the alloy, then hot rolling the alloy, then annealing and pickling the alloy. The alloys were then tested and imaged after annealing and pickling the alloy, and also after subsequent cold rolling of the alloy to various degrees. [Table 3]

[0076] The actual alloy compositions in Table 3 were cold worked to various degrees and Table 4 summarizes the results for various cold work amounts. Figures 4A and 4B show optical micrographs of the actual alloy compositions in Table 3 cold worked to 24% reduction. Figures 5A and 5B show optical micrographs of the actual alloy compositions in Table 3 cold worked to 36% reduction. Figures 6A and 6B show optical micrographs of the actual alloy compositions in Table 3 cold worked to 44% reduction. Figures 7A and 7B show optical micrographs of the actual alloy compositions in Table 3 cold worked to 56% reduction. Table 4 summarizes the experimental data for the actual alloy compositions in Table 4 cold worked to different reduction percentages. [Table 4]

[0077] Example 2 - 50kg scale Alloys within the target ranges of Alloys A4, A7 and A8 were prepared on a 50 kg scale with the actual compositional alloying element values ​​shown in Table 5. The alloys were formed by casting the alloy, then annealing and pickling the alloy, and then hot rolling the alloy. The alloys were then tested and imaged after annealing and pickling the alloy, and also after subsequent cold rolling of the alloy to various degrees. [Table 5]

[0078] The actual alloy compositions of Table 5 for alloys A4, A7 and A8 were cold worked to various degrees and Tables 6A-6C summarize the results for various amounts of cold work. The experimental properties of hardness, strength and elongation for the actual alloy compositions of Table 5 for alloys A4, A7 and A8 are shown in Figure 8. Figures 9-11 show longitudinal stress-strain experimental data for the actual alloy compositions of Table 5 for alloys A4, A7 and A8, respectively, cold worked to various degrees. Figures 12A, 12B and 12C show optical micrographs of the actual alloy compositions of Table 5 for alloys A4, A7 and A8, respectively, cold worked. [Table 6A] [Table 6B] [Table 6C]

[0079] Example 3 Alloys within the target range of A4 alloy were prepared at 170 metric ton scale and 50 kg scale. Alloys within the target range of A7 alloy were prepared at 50 kg scale. The alloys were formed by casting the alloy, then machining the alloy, then hot rolling the alloy, and then annealing and pickling the alloy. The alloys were then tested after annealing and pickling the alloy (labeled as annealed) and also after subsequent cold rolling of the alloy (labeled as cold rolled).

[0080] FIG. 13A shows the E of A4 and A7 alloys prepared at 50 kg scale (laboratory scale) and 170 metric ton scale (mill scale) in 3 wt % sodium chloride aqueous solution measured against a standard calomel electrode (SCE). pit -E ocp The experimental results of corrosion resistance are shown. As shown in FIG. 13A, the A4 alloy had an E of close to or exceeding 700 mV prepared at 170 metric ton scale. pit -E ocp FIG. 13B shows the corrosion current density I of the A4 and A7 alloys prepared in a 50 kg scale (laboratory scale) and a 170 metric ton scale (mill scale) in a 3 wt % sodium chloride aqueous solution. corr The experimental results are shown below.

[0081] Table 7 summarizes some of the experimental results of corrosion resistance for A4 and A7 alloys under different conditions. [Table 7]

[0082] Example 4 Alloys within the target range of A4, A7, B1, B2 and B3 alloys were prepared at a 50 kg scale (laboratory scale). Also, alloys within the target range of A4 alloy were prepared at a 170 metric ton scale. The alloys were formed by casting the alloy, then machining the alloy, then hot rolling the alloy, then annealing and pickling the alloy. The alloys were then tested after annealing and pickling the alloy (labeled as Annealed).

[0083] FIG. 14A shows the E of A4, A7, B1, B2 and B3 alloys prepared at 50 kg scale (laboratory scale) and A4 alloy prepared at 170 metric ton scale (mill scale) in 3 wt % sodium chloride aqueous solution measured against a standard calomel electrode (SCE). pit -E ocp The experimental results of corrosion resistance are shown in FIG. 14B. Corrosion current density I of A4, A7, B1, B2 and B3 alloys prepared at 50 kg scale (laboratory scale) and A4 alloy prepared at 170 metric ton scale (mill scale) in 3 wt% sodium chloride aqueous solution. corr The experimental results are shown below.

[0084] FIG. 15A shows the E of A4, A7, B1, B2 and B3 alloys prepared at 50 kg scale (laboratory scale) and A4 alloy prepared at 170 metric ton scale (mill scale) in 3 wt. % sodium chloride aqueous solution measured for corrosion resistance with standard calomel electrode (SCE) versus pitting corrosion resistance index (PREN). pit -E ocp The experimental results of corrosion resistance are shown in FIG. 15B. Corrosion current density I of A4, A7, B1, B2 and B3 alloys prepared at 50 kg scale (laboratory scale) and A4 alloy prepared at 170 metric ton scale (mill scale) in 3 wt. % sodium chloride aqueous solution measured for corrosion resistance at standard calomel electrode (SCE) versus pitting corrosion resistance index (PREN). corr The experimental results are shown below.

[0085] Example 5 Alloys within the target range of alloy 1 (i.e., A4 alloy), alloy 2 (i.e., A7 alloy), and alloy 4 (i.e., B1 alloy) were prepared on a 50 kg scale. The alloys were formed by casting the alloy, then machining the alloy, then hot rolling the alloy, and then annealing and pickling the alloy. The alloys were then tested after annealing and pickling the alloy (labeled as annealed) and also after subsequent cold rolling of the alloy (labeled as cold rolled).

[0086] FIG. 16A shows the E of Alloy 1 (i.e., A4 alloy), Alloy 2 (i.e., A7 alloy), and Alloy 4 (i.e., B1 alloy) prepared by annealing and cold working in 3 wt. % sodium chloride aqueous solution at 50 kg scale, measured against the standard calomel electrode (SCE). pit -E ocp The experimental results of corrosion resistance are shown in Fig. 16B. Corrosion current density I of Alloy 1, Alloy 2, and Alloy 4 prepared by annealing and cold working in a 50 kg scale in a 3 wt% sodium chloride aqueous solution. corr The experimental results are shown below.

[0087] Table 8 summarizes some of the experimental corrosion resistance results for Alloy 2 and Alloy 4 under different conditions. [Table 8]

[0088] Example 6 An alloy within the target range of Alloy 1 (i.e., A4 alloy) was prepared. FIG. 17 shows the longitudinal and transverse bend angles of Alloy 1 in some examples compared to Type 301 stainless steel. As shown in FIG. 17, the longitudinal bend angle of Alloy 1 is about 84° and the transverse bend angle of Alloy 1 is about 122°, while the longitudinal bend angle of Type 301 alloy is about 64° and the transverse bend angle of Type 301 alloy is about 109°. Both the longitudinal bend angle and the transverse bend angle of Alloy 1 are greater than Type 301 alloy, indicating that Alloy 1 is more ductile than Type 301 alloy. Example 7

[0089] An alloy within the target range of A4 alloy was prepared on a 170 metric ton scale. The alloy was formed by casting the alloy, then machining the alloy, then hot rolling the alloy, then annealing and pickling the alloy. The alloy was then annealed and pickled, and tested after subsequent cold rolling of the alloy.

[0090] FIG. 18 shows the stress-strain experimental results of the A4 alloy prepared at 170 metric ton scale, cold worked longitudinally, transversely, and at 45° from the longitudinal direction. The longitudinal stress-strain curve is measured when the stress is applied in a direction parallel to the rolling direction of the alloy. The transverse stress-strain curve is measured when the stress is applied in a direction perpendicular to the rolling direction of the alloy.

[0091] Although specific embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. In addition, various omissions, substitutions, and modifications of the systems and methods described herein may be made without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as fall within the scope and spirit of the present disclosure.

[0092] It should be understood that features, materials, properties, or groups described in connection with a particular aspect, embodiment, or example are applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, except where incompatible. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of any of the foregoing embodiments. Protection extends to any novel, or any novel combination of features disclosed in this specification (including any accompanying claims, abstract, and drawings), or any novel, or any novel combination of steps of any method or process so disclosed.

[0093] Moreover, certain features described in this disclosure in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a particular combination, one or more features from a claimed combination can, in some cases, be deleted from the combination, and the combination can be claimed as a subcombination or a variation of the subcombination.

[0094] Furthermore, although operations may be shown in the figures or described herein in a particular order, such operations need not be performed in the particular order shown, or in sequential order, to achieve desirable results, nor need all operations be performed. Other operations not shown or described may be incorporated into the exemplary methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the described operations. Furthermore, operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps performed in the illustrated and / or disclosed processes may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be omitted, and other steps may be added. Furthermore, the features and attributes of certain embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, it should be understood that the separation of the components of the various systems in the above implementations should not be understood to require such separation in all implementations, and the components and systems described may generally be integrated together in a single product or packaged in multiple products. For example, any of the components of the energy storage system described herein may be provided separately or may be integrated (e.g., packaged together or attached together) to form an energy storage system.

[0095] For purposes of this disclosure, certain aspects, advantages, and novel features have been described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or implemented to achieve one advantage or group of advantages as taught herein, without necessarily achieving other advantages as may be taught or suggested herein.

[0096] Conditional language such as "can," "could," "might," or "may," unless otherwise specified or understood otherwise within the context in which it is used, is generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not. Thus, such conditional language is not generally intended to imply that the features, elements, and / or steps are in any way required by one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps should be included in or performed in any particular embodiment, with or without user input or prompting.

[0097] Conjunction language such as the phrase "at least one of X, Y, and Z," unless otherwise noted, is understood in the context in which it is generally used to convey that an item, term, etc. can be either X, Y, or Z. Thus, such conjunctions are generally not intended to imply that a particular embodiment requires the presence of at least one X, at least one Y, and at least one Z.

[0098] As used herein, language of degree, such as "approximately," "about," "generally," and "substantially," describes a value, amount, or characteristic that is close to a stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms "approximately," "about," "generally," and "substantially" can refer to an amount that is within 10%, within 5%, within 1%, within 0.1%, and within 0.01% of a stated amount, depending on the desired function or result.

[0099] The scope of the present disclosure is not intended to be limited by the specific disclosure of preferred embodiments in this section or elsewhere herein, but may be defined by the claims, as presented in this section or elsewhere herein, or as presented in the future. The language of the claims should be interpreted broadly based on the language used in the claims, and not limited to the examples described herein or during the prosecution of this application, which examples should be interpreted as non-exclusive.

[0100] The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the devices and methods disclosed herein.

Claims

1. 1. A steel alloy composition comprising: Contains Fe, a hardness of at least about 400 HV; E in 3 wt% sodium chloride aqueous solution ｐｉｔ -E ｏｃｐ A steel alloy composition having a corrosion resistance of at least about 500 mV.

2. 10. The composition of claim 1, wherein the hardness is from about 420 HV to about 500 HV.

3. The above E ｐｉｔ -E ｏｃｐ 10. The composition of claim 1, wherein the corrosion resistance is from about 520 mV to about 800 mV.

4. 10. The composition of claim 1, further comprising a yield strength of at least about 1100 MPa.

5. 10. The composition of claim 1, further comprising a ductility of at least about 60° bend angle at a thickness of 1.6 mm.

6. The composition of claim 1 , wherein martensite formation begins at about 260K to about 340K.

7. 10. The composition of claim 1, further comprising at least about 12 volume percent martensite.

8. 10. The composition of claim 1, further comprising a yield strength of at least about 1200 MPa.

9. Cr: 15-18% by weight, Ni: 4 to 8% by weight, Mn: 1.5 to 6 wt. %, and The composition of claim 1 further comprising Fe:Bal.

10. 10. The composition of claim 9, further comprising: up to about 0.25 wt.% N.

11. 10. The composition of claim 9, further comprising: up to about 2 wt.% Mo.

12. C: up to about 0.03% by weight, Si: up to about 0.75 wt.%; P: up to about 0.045 wt. %, and 10. The composition of claim 9, further comprising: up to about 0.03 wt.% of S.

13. Cu: up to about 0.5 wt. %; Co: up to about 0.8 wt. %; Al: up to about 0.03 wt. %; Ti: up to about 0.03 wt. %; and The composition of claim 9, further comprising up to about 0.05 wt.% of B.

14. 14. The composition of claim 13, further comprising up to about 0.05 wt.% each of at least one additional element, said at least one additional element totaling up to about 0.15 wt.%.

15. 1. A process for preparing an alloy, comprising: Casting a steel alloy comprising Fe; subjecting the steel alloy to a treatment step selected from the group consisting of hot working, annealing, pickling, and combinations thereof to form a treated steel alloy; and The treated steel alloy is cold worked to have a hardness of at least about 400 HV and an E of at least about 500 mV in a 3 wt. % aqueous sodium chloride solution. ｐｉｔ -E ｏｃｐ A process comprising forming a corrosion-resistant cold-work steel alloy.

16. 16. The process of claim 15, wherein the treated steel alloy is cold worked to a thickness reduction of at least about 30%.

17. 16. The process of claim 15, wherein the cold work steel has a thickness of about 0.01 mm to about 4 mm.

18. 16. The process of claim 15, further comprising machining the cold work steel.

19. 16. The process of claim 15, wherein the steel alloy is hot worked prior to annealing.

20. 16. The process of claim 15, wherein annealing is performed prior to hot working the steel alloy.

21. 16. The process of claim 15, wherein treating the steel alloy occurs before cold working the treated steel alloy.

22. A vehicle comprising a body comprising the composition of claim 1.

23. 23. The vehicle of claim 22, wherein the body comprises an exterior body, the exterior body comprising the steel alloy.

24. 23. The vehicle of claim 22, wherein the steel alloy is uncoated.

25. 23. The vehicle of claim 22, wherein no corrosion protectant is disposed on the steel alloy.

26. 26. The vehicle of claim 25, wherein the corrosion protection agent is a paint.

27. 23. The vehicle of claim 22, wherein the vehicle is an electric vehicle having an electric motor.

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