Structural components and methods for vehicles

Abstract

The present disclosure relates to a structural component for a vehicle framework configured at least in part to support a compressive load. The structural component includes a main member extending longitudinally from a load-bearing end to an opposite end. The main member further includes a main soft zone having lower mechanical properties than other zones of the main member. The main soft zone further includes a first portion and a second portion having substantially constant first and second mechanical properties, respectively. The mechanical property of the first portion is lower than the mechanical property of the second portion.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of EP22382876.5, filed September 22, 2022. [Technical Field]

[0002] SUMMARY The present disclosure relates to a structural component for a vehicle framework, the structural component being configured at least in part to support a compressive load. [Background technology]

[0003] Vehicles such as automobiles incorporate structural frameworks designed to withstand loads that the vehicle may be subjected to during its lifetime, and the structural frameworks are further designed to withstand and absorb impacts, for example, in the event of a collision with another vehicle or road structure.

[0004] The demand for lightweighting in the automotive industry has led to the development and implementation of lightweight materials or components, as well as related manufacturing processes and tools. The demand for lightweighting is driven, among other things, by the goal of reducing CO2 emissions. Increasing concern for occupant safety has led to the adoption of materials that improve the vehicle's integrity during a crash while also improving energy absorption.

[0005] A process known as hot form die quenching (HFDQ) typically uses boron steel sheet to create stamped parts with ultra-high strength steel (UHSS) properties, for example, tensile strengths of 1.500 MPa or 2.000 MPa or greater. The increased strength allows thinner gauge material to be used, which results in weight savings over conventional cold-stamped mild steel parts. Throughout this disclosure, UHSS can be considered a steel that has an ultimate tensile strength of 1.000 MPa or greater after the press hardening process.

[0006] In the HFDQ process, the blank to be hot-formed is heated to a predetermined temperature, for example, above the austenitizing temperature (particularly between Ac3 and, for example, the evaporation temperature of the coating on the blank). A furnace system can be used for this purpose. Depending on specific needs, the furnace system can be supplemented with additional heaters, for example, induction or infrared. By heating the blank, its strength decreases and its deformability increases, thus facilitating the hot stamping process.

[0007] Several ultra-high strength steels (UHSS) are known for hot stamping and hardening. The blank may be made of coated or uncoated boron steel, such as Usibor® (22MnB5), available from ArcelorMittal.

[0008] Hot forming die hardening is sometimes referred to as "press hardening" or "hot stamping," and these terms are used interchangeably throughout this disclosure.

[0009] Typical vehicle parts that can be manufactured using the HFDQ method include door beams, bumper beams, cross / side members, A / B pillar reinforcements, front and rear rails, seat cross members and roof rails.

[0010] Hot forming of boron steel has become increasingly common in the automotive industry due to its excellent strength and formability. Thus, many structural parts that were traditionally cold formed from mild steel are being replaced with hot-formed equivalents, which offer a significant increase in strength. This allows for a reduction in material thickness (and therefore weight) while maintaining the same strength. However, hot-formed parts offer very low levels of ductility and energy absorption in the as-formed state.

[0011] To improve ductility and energy absorption in specific regions of a component, it is known to introduce softer regions within the same component. This locally improves ductility while maintaining the required overall high strength. By locally tailoring the microstructure and mechanical properties of specific structural components so that they contain very high strength (very hard) regions, i.e., high ultimate tensile strength and high yield strength, and regions with increased ductility (softer) regions, i.e., lower ultimate tensile strength and lower yield strength and increased elongation before fracture, it may be possible to improve their overall energy absorption, maintain their structural integrity during crash situations, and reduce their overall weight. Such soft zones can also favorably change the kinematic behavior of the component in the event of collapse under impact.

[0012] A known method for creating regions of increased ductility ("soft zones" or "soft zones") in a vehicle structural component involves providing a tool with a pair of complementary upper and lower die units, each having a separate die element (steel block). The blank to be hot-formed is preheated, for example by a furnace system, to a predetermined temperature, for example above the austenitizing temperature, to reduce its strength, i.e., to facilitate the hot stamping process.

[0013] Die elements may be designed to operate at different temperatures to achieve different cooling rates in different zones of the part being formed during the quenching process, resulting in different material properties in the final product, such as softer regions that generally have lower ultimate tensile strength and yield strength but may allow for more elongation before fracture. For example, one die element may quench a corresponding region of the part being produced at a high cooling rate, thereby rapidly reducing the part's temperature and cooling it to obtain a hard martensitic microstructure. Another adjacent die element may be heated to ensure that the corresponding portion of the part being produced cools at a slower cooling rate to obtain a softer microstructure, including, for example, bainite, ferrite, and / or pearlite. Such a region of the part may remain at a higher temperature than the rest of the part when it leaves the die.

[0014] Other methods for obtaining hot stamped parts with regions of different mechanical properties include, for example, controlled or differential heating before stamping and local heat treatment after the stamping process to change the local microstructure and obtain different mechanical properties. Further possibilities include the use of patchwork blanks and tailor welded blanks (TWBs) that combine different thicknesses and / or materials of the blanks.

[0015] Several methods of differential heating before stamping are known. In one example, a nozzle or set of nozzles can emit a fluid flow, e.g., compressed cooling air, towards a portion of the blank to be cooled, e.g., while the bank is still in an oven. Other portions of the blank can be maintained at a higher temperature. This makes it possible to obtain a blank with a tailored temperature profile along its length and / or width. In some examples, the blank can undergo further heating in an oven before undergoing the stamping process.

[0016] In another example, an array of independently controllable infrared heaters can be used to control the temperature along the blank.

[0017] Some elements of an automobile's structural framework, such as front and rear rails, seat cross members, and roof rails, may be specifically designed to support compressive loads. That is, these sections are positioned to receive compressive loads in typical crash scenarios. These and other structural components may have one or more regions with a substantially U-shaped (also known as a "hat" shape) cross section. These structural components can be manufactured in a variety of ways and made from a variety of materials. Lightweight materials that improve energy absorption during a crash while also maintaining the integrity of the vehicle are desired.

[0018] Throughout this disclosure, a U-shaped cross-section may be understood to refer to a structural member having, in cross-section (generally, in a transverse plane substantially perpendicular to the longitudinal axis of the structural member), a bottom wall and two side walls. U-shaped cross-sections are generally known to have a good ratio of moment of inertia to weight. The two side walls may form an obtuse angle with the bottom wall, for example, an angle between 90° and 135°. The two side walls may include outwardly extending lateral flanges. The bottom wall and side walls may be substantially straight, but may also include transitions, curves, recesses, or protrusions.

[0019] In addition to the ultra-high strength steels mentioned above, more ductile steels can be used in portions of the structural framework that require energy absorption. Examples of ductile steels include Ductibor® 500, Ductibor® 1000, and CRL-340LA.

[0020] UHSS can exhibit tensile strengths as high as 1500 MPa or even 2000 MPa or more, especially after press hardening operations. Once hardened, UHSS can have a martensitic microstructure, which allows for increased ultimate tensile strength and yield strength per unit weight.

[0021] Some ductile steels can also be heated and pressed (i.e., used in hot stamping processes), but do not have a martensitic microstructure after the process. As a result, they have lower tensile strength and yield strength than UHSS, but they have higher elongation to break.

[0022] Although ductile steel allows for energy absorption by structural components, it may not be easy to control and predict how the structural components may behave during a vehicle crash, and it may not be easy to enhance energy absorption while maintaining a certain structural integrity of the structural components.

[0023] The present disclosure aims to provide controlled deformation of and improved energy absorption by structural components for vehicle frameworks when subjected to loads, particularly compressive loads. Summary of the Invention

[0024] In a first aspect, a structural component for a vehicle framework is provided. The structural component is at least partially configured to support a compressive load. The structural component includes a main member extending along a longitudinal direction of the main member from a load-bearing end to an opposite end. The main member includes a main soft zone having a lower mechanical property than other zones of the main member. Further, the main soft zone includes a first portion having a substantially constant first mechanical property and a second portion having a substantially constant second mechanical property, the first mechanical property being lower than the second mechanical property.

[0025] The introduction of a primary soft zone, comprising first and second portions with first and second mechanical properties, respectively, provides a primary member with the ability to effectively absorb energy during a crash while controlling the kinematics of deformation. The first portion, having lower mechanical properties than the second portion, can deform first before the second portion and before the remainder of the primary member when the structural component is subjected to a compressive load. The primary member may be able to absorb more energy during compression with a high degree of deformation predictability. Meanwhile, the remaining primary member, having higher mechanical properties, provides a limit to deformation, e.g., maintaining the interior space of the vehicle. This can enhance the safety of vehicle occupants.

[0026] A compressive load may be understood as a load or component of a load that acts substantially parallel to the length of a structural part, tending to shorten the part. Parts or areas within an automobile framework that may be particularly subject to compressive loads in different crash or impact scenarios include front rails, rear rails, energy absorbers, roof rails, and seat cross members. Thus, the examples disclosed herein may be particularly beneficial when used with this type of part.

[0027] Throughout this disclosure, "at least partially configured to support a compressive load" may be understood to mean that a portion of a component or the entire component is expected to absorb primarily compressive loads in the event of an impact or collision, i.e., compressive loads are expected to be higher, although other loads may occur as well.

[0028] Also, throughout this disclosure, references to "mechanical properties of a part" may be understood as the mechanical properties of the material forming the part. Thus, unless otherwise specified, comparisons of mechanical properties of parts, components, or other things are to the material, and not to its shape or other particularities.

[0029] Higher mechanical properties can be understood herein as higher ultimate tensile strength and / or higher yield strength, and lower mechanical properties can be understood herein as lower ultimate tensile strength and / or lower yield strength. Ultimate tensile strength and yield strength are considered herein as material properties of the material after the manufacturing process. Ultimate tensile strength and yield strength can be determined in a standardized tensile strength test, for example, using A30, A50, or A80 test specimens in a quasi-static loading test.

[0030] Comparisons between lower and higher mechanical properties should be made using the same test conditions and specimen size. To compare the yield strength of different parts, specimens formed of the same material as the parts of the structural component, e.g., the soft zone(s), can be prepared and tested on a universal testing machine (UTM).

[0031] Throughout this disclosure, "parts having substantially constant mechanical properties" can be considered parts made of the same material subjected to the same heat treatment. The resulting mechanical properties can be substantially the same within normal manufacturing tolerances. In an example, each part can have an average magnitude of a mechanical property (such as hardness, yield strength, or ultimate tensile strength) and local magnitudes that deviate from the average magnitude by within ±15%.

[0032] In an example, a primary soft zone in a structural component is formed by subjecting the primary soft zone to a different temperature treatment than other zones of the primary member.

[0033] In some examples, the primary soft zone of the structural component may further include a third portion having a substantially constant third mechanical property, which may be higher than the second mechanical property. Additionally, the primary soft zone may include four or more portions disposed adjacent to one another.

[0034] In an example, the portions of the primary soft zone may be arranged along the longitudinal direction based on their mechanical properties, i.e., portions with lower mechanical properties may be located closest to the load-bearing end, and portions with higher mechanical properties may be located further from the load-bearing end. This may result in a structural component that can effectively absorb energy during a collision while controlling the kinematics of deformation and maintaining the interior space of the vehicle. A first portion with lower mechanical properties than a second portion may deform first before the second portion and before the rest of the primary member when the structural component is subjected to a compressive load.

[0035] In other examples, the portions of the primary soft zone may be arranged along the longitudinal direction such that the portions having higher mechanical properties are located closest to the load-bearing end and the portions having lower mechanical properties are located further from the load-bearing end. Additionally, the portions of the primary soft zone may be arranged along the longitudinal direction based on other parameters or considerations.

[0036] In some instances, the primary soft zone may span the entire width (or entire cross section) of the main member of the structural member. In other instances, the primary soft zone may not cover the entire width of the main member. For example, in the case of a U-shaped cross section, the primary soft zone may extend from one side flange to the opposite side flange, or may cover only the side walls and bottom, or only a portion of the side walls and bottom of the U-shape.

[0037] In examples, a structural component may include a secondary soft zone spaced longitudinally from a primary soft zone. The secondary soft zone may be different from the primary soft zone. For example, the secondary soft zone may include more or fewer portions with different mechanical properties than the primary soft zone, and the placement of portions within the secondary soft zone may be based on other parameters or considerations.

[0038] In some examples, the main members of the structural component outside the soft zone(s) have an ultimate tensile strength primarily of 1.000 MPa or greater, specifically 1.200 MPa or greater, and more specifically 1.500 MPa or greater.

[0039] In an example, the main member defines a substantially U-shaped cross-section including a bottom wall, a first side wall, and a second side wall. Additionally, the main member may include a flange extending outwardly from the side wall.

[0040] In some examples, the width of the transition zone between portions of the soft zone(s), i.e., between the first and second portions of the main soft zone, or between the main member and the soft zone(s), may be less than 30 mm, specifically between 20 mm and 5 mm. The width of the transition zone may depend on manufacturing parameters, such as the temperature difference between adjacent portions, or the manufacturing procedure.

[0041] Furthermore, in examples, the difference between the average yield strength of two adjacent portions may be greater than 10%, particularly greater than 15%, and in some cases greater than 20%.

[0042] In some examples, the primary member can include a region made of hardened steel, specifically press-hardened steel, and the primary member can include a region made of ultra-high strength steel (UHSS) having an ultimate tensile strength of 1,000 MPa, specifically 1,500 MPa or greater.

[0043] Also, the amount of energy absorption along the length of the main member can be tailored in different ways. For example, more energy can be absorbed as the cross-sectional area of ​​the main member increases. Thus, energy absorption can increase from a first cross section of the main member closer to the potential impact point to cross sections further away.

[0044] In some examples, the main member may include one or more ribs that may extend across the bottom wall or one of the first and second side walls.

[0045] Throughout this disclosure, a rib may be understood as an elongated, substantially straight portion of a main member for localized reinforcement. Ribs can be manufactured during the stamping process. In some examples, the rib may be formed by using a patchwork blank, i.e., a patch blank is welded (e.g., spot welded) to the main blank prior to the stamping process. In other examples, the rib may be formed as a deformed portion of the same main blank.

[0046] The presence of one or more ribs in the main member can help tailor the deformation behavior of a structural component. Ribs, which are less ductile and more resistant than the main member, can help create specific bending locations within the structural component. This can optimize the deformation of the structural component. This can increase energy absorption, especially when the structural component is configured to support compressive loads.

[0047] The number, location and extension of the portions having different mechanical properties from the rest of the main member, as well as the number, location and extension of the ribs in the structural component, may be selected according to the desired behavior of the structural component with respect to deformation, in particular under compressive loading of the main member resulting from, for example, a (simulated) impact or collision.

[0048] In an example, the structural component may include an additional component attached to the main member. The additional component may be, for example, a plate or cover attached to a flange of the main member. The additional component may also be similar in size and shape to the main member, i.e., the structural component is formed by two similar components. In an example, the main member and the additional component may both have a U-shaped or hat-shaped cross section with an outwardly extending flange. In an example, the flange may also be configured to have lower mechanical properties. The first and subsequent portions of the soft zone may extend within the flange, or the flange may form a different portion of the soft zone, i.e., the flange may be subjected to a different heat treatment than the sidewalls and bottom of the U-shaped cross section. The flange may, for example, have lower strength and higher ductility than the adjacent main soft zone.

[0049] In some examples, the soft zone(s) comprising the first and second (and optionally further) portions described above may be formed in additional components as well.

[0050] In a further aspect, a method is provided for manufacturing a structural component at least partially configured to support a compressive load to obtain a structural component for a vehicle framework as described in this disclosure.

[0051] The method includes providing a primary blank. The method further includes at least partially heating the primary blank to a temperature above an austenitizing temperature, wherein adjacent first and second portions are heated differently from other portions of the primary blank, and press-hardening the heated primary blank to form a primary member of a structural component. The formed primary member includes a primary soft zone having a lower mechanical property than other zones of the primary member. Further, the primary soft zone includes a first portion with a substantially constant first mechanical property and a second portion with a substantially constant second mechanical property. Further, the first mechanical property is lower than the second mechanical property.

[0052] The method can improve the deformation behavior of a structural component configured to support a compressive load, for example, allowing for tailoring how the structural component deforms during a vehicle crash, thus enhancing energy absorption by the structural component.

[0053] A primary blank is herein understood to be a blank, such as a metal sheet or flat metal plate, from which the primary component is formed. The primary blank may be made of hardenable steel, in particular boron steel. The thickness of the primary blank may typically be 1 to 2.5 mm.

[0054] In this example method, the first portion can be positioned closer to the load-receiving end than the second portion.

[0055] In some examples of the method, the heating step includes substantially uniformly heating the primary blank at a temperature above the austenitizing temperature and then cooling a portion of the primary blank, particularly at a temperature below the austenitizing temperature.

[0056] In some examples of the method, the cooling may include blowing air through a nozzle against the portion of the primary blank to be cooled. The portion to be cooled may extend substantially transversely of the primary blank and / or substantially longitudinally of the primary blank.

[0057] This approach to cooling specific portions of the primary blank can create precisely defined temperature regions and gradients along and / or across the primary blank. Thus, the cooling effect can be localized and the mechanical properties of the different portions can be precisely controlled. This allows for predictable, substantially constant mechanical properties within each portion and relatively small transition zones between them.

[0058] In some further examples, the cooling may include reducing the temperature of the cooled portion by 100 degrees relative to other portions of the main member, or more specifically, by 200 degrees relative to other portions of the main member.

[0059] In some examples, the cooling may be performed using an array or matrix of nozzles, so that the nozzles can precisely define the portion of the main member that is cooled.

[0060] In an example, the nozzle may propel compressed air at an overpressure of at least 2 bar, in particular 3 bar, more particularly 4 bar, where overpressure is to be understood as the pressure difference between atmospheric pressure under normal conditions and the total pressure of the compressed air, i.e., static pressure plus dynamic pressure.

[0061] In some examples, the nozzles can include at least one tangential nozzle. The tangential nozzle can propel compressed air with a directional component substantially parallel to the process plane, i.e., the surface of the part. This tangential nozzle can therefore create a flow seal that can prevent air from other nozzles from reaching portions of the primary blank. Thus, the tangential nozzle can be used to control temperature gradients along and / or across the primary blank.

[0062] In an example, the nozzle may include a nozzle configured to create a negative pressure region at a desired location within the heating facility, which may be suitable for separating regions of different air temperatures. [Brief explanation of the drawings]

[0063] Non-limiting examples of the present disclosure are described below with reference to the accompanying drawings. [Figure 1] 1 illustrates a schematic diagram of an example of a structural component for a vehicle that is at least partially configured to support a compressive load. [Figure 2] 1 shows two cross sections of an example structural component diagrammatically. [Figure 3] 2A and 2B illustrate diagrammatically another example of a structural component for a vehicle configured at least in part to support a compressive load. [Figure 4] 10 shows a schematic representation of the post-quench yield strength of an exemplary primary member as a function of longitudinal position. [Figure 5] 2A and 2B illustrate schematic diagrams of further examples of structural components for vehicles that are at least partially configured to support compressive loads. [Figure 6] 6 shows a schematic cross section of the structural component of FIG. 5; [Figure 7] 2A and 2B illustrate schematic diagrams of further examples of structural components for vehicles that are at least partially configured to support compressive loads. [Figure 8] 2A and 2B illustrate diagrammatically another example of a structural component for a vehicle configured at least in part to support a compressive load. [Figure 9]2A and 2B illustrate schematic diagrams of further examples of structural components for vehicles that are at least partially configured to support compressive loads. [Figure 10] 1 is a flowchart of a method for manufacturing a structural component at least partially configured to support a compressive load.

[0064] The drawings depict exemplary implementations and are used only as an aid in understanding the claimed subject matter and are not intended to limit it in any way. DETAILED DESCRIPTION OF THE INVENTION

[0065] 1 schematically illustrates a structural component 100 for a vehicle configured, or at least partially configured, to support a compressive load. The structural component 100 includes a main member 110 extending longitudinally from a load-bearing end 111 to an opposite end 112 of the main member 110. The main member 110 includes a main soft zone 170 having a lower mechanical property than other zones of the main member. Furthermore, the main soft zone 170 includes a first portion 120 having a substantially constant first mechanical property and a second portion 130 having a substantially constant second mechanical property. Furthermore, the first mechanical property is lower than the second mechanical property.

[0066] In the example shown in FIG. 1, the first portion 120 is positioned closer to the load-receiving end 111 than the second portion 130, but in other examples, the second portion 130 may be positioned closer to the load-receiving end 111 than the first portion 120.

[0067] 1, the primary soft zone 170 of the primary member 110 may further include a third portion 140 of a substantially constant third mechanical property. The third portion 140 may be disposed adjacent to the second portion 130. Furthermore, the third mechanical property may be higher than the second mechanical property.

[0068] Thus, the main member 110 may include a main soft zone 170 that includes two or more unique portions 120, 130, 140 adjacent one to the other in terms of mechanical properties. The portions 120, 130, 140 may be arranged based on mechanical properties, i.e., the portion having the lowest mechanical properties closest to the load-bearing end 111. One aspect of this configuration is that in the case of a compressive load (in the case of an impact), subsequent portions from the load-bearing end have increasing strength and deform in a controlled manner, i.e., first the portion closest to the load-bearing end with the lowest mechanical properties, then the adjacent subsequent portion with higher mechanical properties, etc.

[0069] Alternatively, the portions 120, 130, 140 may be positioned based on other parameters or considerations, and thus the positioning of the portions 120, 130, 140 can be adjusted to tailor the behavior of the structural component 100 when subjected to compressive loads.

[0070] The primary member 110 of the structural component 100 in the example of FIG. 1 may have an ultimate tensile strength outside the primary soft zone 170 of primarily 1.000 MPa or greater, specifically 1.200 MPa or greater, and more specifically 1.500 MPa or greater.

[0071] In one example, the soft zone may have a yield strength of 300 to 950 MPa. For example, the soft zone may have a first portion having a yield strength of 300 to 500 MPa (e.g., an average of about 400 MPa), a second portion having a yield strength of 400 to 550 MPa (e.g., an average of about 475 MPa), a third portion having a yield strength of 650 to 800 MPa (e.g., an average of about 725 MPa), and a fourth portion having a yield strength of 750 to 950 MPa (e.g., an average of about 850 MPa).

[0072] 1 illustrates that the main member 110 can substantially define a U-shaped or "hat-shaped" cross-section including a bottom wall 113 and first and second side walls 114, 115. The bottom wall 113 can be substantially perpendicular to the first and second side walls 114, 115. In a further example, the bottom wall 113 can define an angle other than 90 degrees relative to the first and second side walls 114, 115. The structural component 100 can define other cross-sectional shapes. For example, the structural component 100 can define an L-shaped cross-section, a W-shaped cross-section, etc.

[0073] Furthermore, the radius of curvature between the bottom wall 113 and the first and second side walls 114, 115 can be adapted according to the specifications of the structural component 100, ie the mechanical properties of the materials used, the desired maximum local strength, etc.

[0074] 1, the structural component 110 may include first and second flanges 116, 117 extending outwardly from first and second side walls 114, 115, respectively. The flanges 116, 117 provide convenient attachment points for connecting the structural component 110 to other portions of the vehicle, such as other components of the vehicle's structural framework. The radius of curvature between the first and second side walls 114, 115 and the flanges 116, 117 may also vary according to the specifications of the structural component 110, as previously discussed.

[0075] In the illustrated example, the primary soft zone extends across the entire width of the primary member, at least over a portion of its length. That is, in the U-shaped cross section of this example, the primary soft zone extends from one side flange to the other. In other examples, the soft zone may extend from one side wall to the other without extending into the flange. In some cases, secondary soft zones can be formed in the flange by localized softening, for example, using a localized heat treatment. For example, the connection regions of the flange can be softened, i.e., their mechanical properties can be reduced. Such localized softening can improve the kinematics in the event of an impact and, in particular, delay or avoid fracture of the joint at the flange.

[0076] In some examples, the main member 110 may be made from a boron steel such as Usibor®, for example, Usibor® 1500 (22MnB5 steel with or without a protective coating), Usibor® 2000 (37MnB5), or any martensitic or ultra-high strength steel (UHSS). Usibor®, Ductibor®, and 22MnB5 are commercially available from ArcelorMittal. CRL-340LA is commercially available from SSAB.

[0077] Usibor® 1500 is supplied in the ferrite-pearlite phase. This is a fine grain structure distributed in a uniform pattern. Its mechanical properties are related to this structure. After heating, the hot stamping process, and subsequent quenching, a martensitic microstructure forms. This results in a significant increase in tensile strength and yield strength.

[0078] The composition of Usibor® 1500 is summarized below in weight percent (the remainder is iron (Fe) and impurities): Maximum carbon (C) (%): 0.25 Maximum silicon (Si) (%): 0.4 Maximum manganese (Mn) (%): 1.4 Maximum phosphorus (P) (%): 0.03 Maximum sulfur (S) (%): 0.01 Aluminum (Al) (%): 0.01 to 0.1 Maximum Titanium (Ti) (%): 0.05 Maximum Niobium (Nb) (%): 0.01 Maximum copper (Cu)(%):0.20 Maximum boron (B) (%): 0.005 Maximum Chromium (Cr) (%): 0.35

[0079] Usibor® 2000 is an example of another boron steel, 37MnB5, that has even higher strength. After the hot stamping die quenching process, Usibor® 2000's yield strength can be 1400 MPa or greater, and its ultimate tensile strength can be greater than 1800 MPa.

[0080] The composition of Usibor® 2000 is summarized below in weight percent (the remainder is iron (Fe) and impurities): Maximum carbon (C) (%): 0.36 Maximum silicon (Si) (%): 0.8 Maximum manganese (Mn) (%): 0.8 Maximum phosphorus (P) (%): 0.03 Maximum sulfur (S) (%): 0.01 Aluminum (Al) (%): 0.01 to 0.06 Maximum Titanium (Ti) (%): 0.07 Maximum Niobium (Nb) (%): 0.07 Maximum copper (Cu)(%):0.20 Maximum boron (B) (%): 0.005 Maximum Chromium (Cr) (%): 0.50 Maximum Molybdenum (Mb) (%): 0.50

[0081] Boron steels such as 22MnB5 or 37MnB5 may be coated with an aluminum-silicon coating to avoid decarburization and scale formation during the forming process.

[0082] Several 22MnB5 and other boron steels with similar chemical compositions are commercially available. However, the exact amounts of each element in 22MnB5 steel may vary slightly depending on the manufacturer. Other ultra-high strength steels include BTR 165, available from Benteler.

[0083] Figure 2 shows two cross sections of an example structural component, which may be part of the same structural component, i.e., the structural component may have a cross section that varies along its length, or the cross sections may correspond to different structural components.

[0084] Although not shown in the example of FIG. 2 , the bottom wall 113 may be curved or may include a recess or protrusion along its bottom. This also applies to the sidewalls 114, 115, which are not necessarily perfectly straight. The sidewalls 114, 115 may include straight sections with curved transition zones between the straight sections. In addition, the sidewalls 114, 115 may or may not be symmetrical. For example, the height of the first sidewall 114 may be different from the height of the second sidewall 115. In some examples, the height along the length of the first sidewall 114 and / or the second sidewall 115 may also vary. In examples, the width of the bottom wall 113 may be different from the height of the first and / or second sidewalls 114, 115. Other examples may include any combination of the above examples.

[0085] The flanges 116, 117 may be shaped and sized to sit on a particular vehicle component and may be used to join the structural component to other components, such as other vehicle framework components.

[0086] 3 schematically illustrates another example of a structural component 100 for a vehicle, the structural component being configured, or at least partially configured, to support a compressive load. In this example, a primary member 110 includes a primary soft zone 170 that includes three portions 120, 130, 140 that have lower yield strength and / or ultimate tensile strength than the remainder of the primary member 110. The three portions 120, 130, 140 may be more ductile than the remaining stiffer portions of the primary member. In particular, the three portions may have higher elongation to break and / or increased reduction in area before break.

[0087] Additionally, the three sections 120, 130, 140 have different mechanical properties due to the different heat treatments they undergo. Other numbers of sections, for example, four or more, as well as other relative sizes, may be included in a structural component 100 according to the present disclosure.

[0088] In the illustrated example, the local yield strength of each portion 120, 130, 140 may deviate from the average yield strength of the respective portion by no more than ±15%. Furthermore, in some examples, the yield strength of each portion 120, 130, 140 may vary by less than 10% within each portion, i.e., the magnitude of the yield strength at the load-bearing end of portion 120 may be substantially constant.

[0089] 3, the main member 110 may include a transition zone 150 between the soft zone 170 and other zones of the main member, the transition zone 150 having a width of less than 30 mm, specifically between 20 mm and 5 mm. The width of the transition zone 150 may depend on manufacturing parameters such as the temperature difference between adjacent portions or the procedure followed to manufacture the structural component.

[0090] The transition zones 150 between adjacent portions 120, 130, 140 of the soft zone 170 may have the same width as described above. Thus, the yield strength in the transition zone 150 may change abruptly, i.e., from a relatively high yield strength at the end of the transition zone 150 adjacent the main member 110 to a relatively low yield strength at the end of the transition zone 150 adjacent the main soft zone 170.

[0091] In the illustrated example, as also seen in FIG. 4, the first portion 120 located closest to the load-bearing end 111 of the main member 110 is the "softest" and most ductile portion. Ductility (e.g., measured as elongation at break or reduced area at break at a given test condition) may be highest in this portion, but the yield strength and ultimate tensile strength are lower. Furthermore, in some examples, all portions 120, 130, 140 of the primary soft zone 170 are arranged along the longitudinal direction by increasing mechanical properties, i.e., ordered from low to high based on the yield strength of the material forming the portion. This is also shown in FIG. 4.

[0092] The difference between the average yield strengths of two adjacent portions 120-130, 130-140 may be greater than 100 MPa, 150 MPa, or 200 MPa. In examples, adjacent portions may have a difference in average yield strength of greater than 10%, specifically greater than 15%, and more specifically greater than 20%. In some examples, the difference between the average yield strengths of two adjacent portions may not be the same as the difference between the average yield strengths of two other adjacent portions. For example, the difference between the average yield strengths of portions 120, 130 may be 10%, while the difference between the average yield strengths of portions 130, 140 may be 15%.

[0093] As in the example of FIG. 1, the primary soft zone 170 extends across substantially the entire cross section or width of the primary member.

[0094] 4 is a simplified graph showing the average cross-sectional yield strength of the structural component of FIG. 3 as a function of longitudinal position. The horizontal axis represents longitudinal position along the structural component 100 from the load-bearing end 111 to the opposite end 112, i.e., the load-bearing end 111 corresponds to the center of the coordinate system. The longitudinal axis represents the average cross-sectional yield strength after the structural component has been quenched, i.e., press-hardened and then brought to room temperature.

[0095] Note that the reference numbers in Figure 4 are associated with features in Figure 3. Thus, the area of ​​the graph with a given reference number refers to the yield strength of the corresponding feature in Figure 3, rather than the feature itself.

[0096] For materials typically used when hot stamping the structural components of the present disclosure, yield strength (or tensile strength) and ductility are inversely related, i.e., as the microstructure of the material changes and yield strength increases, ductility decreases, and vice versa.

[0097] 4 thus shows that the yield strength at the load-bearing end 111 of the main member 110 is relatively high and nearly constant. Then, before reaching the first portion 120, the yield strength of the main member 110 decreases abruptly (and therefore the ductility increases) in a first transition zone 150. This change in mechanical properties occurs over a relatively short width, for example, on the order of 20 or 30 mm. After this first transition zone 150, the main member 110 comprises a first portion 120 with low strength and high ductility. The mechanical properties of this first portion 120 do not change significantly along the longitudinal direction because the heat treatment is essentially homogeneous for the first portion 120.

[0098] The local yield strength of the main member is higher in a second transition zone 150 after the first portion 120. A second plateau after the second transition zone 150 corresponds to the second portion 130, and the same occurs between the second portion 130 and the third portion 140, and between the third portion 140 and the remainder of the main member 110, i.e., the opposite end 112. As can be seen in FIG. 4 , the yield strength gradients in the different transition zones 150 can be different.

[0099] Note that Figure 4 does not include magnitudes of intensity and longitude, as it serves merely as an example of the present disclosure. Also, while the width of some of the transition zones may appear relatively large compared to the length of portions of the main soft zone, this is done explicitly to illustrate potential differences in yield strength gradients. The microstructures that can be obtained can be controlled by appropriate temperature treatment.

[0100] As previously mentioned, portions 120, 130, 140 may be positioned along the length based on other parameters or considerations. Furthermore, portions 120, 130, 140 do not necessarily have to be positioned between regions of high mechanical properties, i.e., portions may be positioned at the ends of structural component 100.

[0101] 5 shows a schematic diagram of a further example of a structural component 100 for a vehicle, where the structural component is configured, or at least partially configured, to support a compressive load. In this example, the structural component 100 may be a front or rear rail of the vehicle.

[0102] In this example, the primary member 110 includes a primary soft zone 170 having three portions 120, 130, 140 that have lower yield strength and / or ultimate tensile strength than the remainder of the primary member 110. The three portions 120, 130, 140 may be more ductile than the remaining harder portions of the primary member. In particular, the three portions 120, 130, 140 may have higher elongation to break and / or increased reduction in area before break. Note that the three portions 120, 130, 140 in FIG. 5 are shown schematically with dashed lines, and the transition regions between the portions are not shown.

[0103] Additionally, as described in the above example, the three sections 120, 130, 140 have different mechanical properties. Other numbers of sections, such as four or more, as well as other relative sizes, may be included in the structural component 100 according to the present disclosure.

[0104] In this example, the structural component includes an additional component 180 attached to a main member 110. The additional component 180 may be of a similar size and shape as the main member 110, i.e., the structural component 100 may be formed by two similar components 110, 180. Furthermore, the additional component 180 may also include a portion with a lower yield strength at the same location as the main member 110. More precisely, the main member 110 and the additional component 180 may have substantially the same mechanical properties along their lengths. That is, in this example, the structural component is substantially symmetrical with respect to the mechanical properties.

[0105] 5, the main member 110 and the additional member 180 have substantially L-shaped cross sections, each comprising a side wall 160 and a horizontal wall 190. The horizontal wall 190 further comprises an outwardly extending flange 165.

[0106] 5, the flanges 165 may be configured to contact the sidewalls 160 of other components, i.e., the flanges 165 of the main component 110 may be configured to contact the sidewalls 160 of the additional component 180, or vice versa. The main component 110 and the additional component 180 may be joined at the flanges, thereby forming a substantially rectangular closed cross section between the main component 110 and the additional component 180.

[0107] Additionally, the flange(s) 165 and the portions of the sidewall(s) 160 configured to contact them can be made from a material having lower mechanical properties than the portions 120, 130, 140 of the main member 110 and the additional component 180. For example, the most ductile portions (e.g., portion 120) of the main member 110 and the additional component 180 can have an average yield strength of about 600 MPa or more, while the corresponding portions of the flange 165 and the sidewall 160 can have a yield strength of about 550 MPa or less. Providing a softer flange can increase the toughness of the joint, e.g., spot weld, between the main member 110 and the additional component 180 in the event of a crash. At the same time, it improves the overall dynamic response of the component 100 and allows for better control of deformation.

[0108] FIG. 6 shows a schematic cross section of the structural component 100 of FIG.

[0109] As previously mentioned, the main member 110 and the additional component 180 may be attached at their flanges 165 to define a substantially rectangular closed cross section.

[0110] In some examples, the geometries of the parts may be different, for example, they may define a substantially square closed cross section, and the radii of curvature of the parts may be different.

[0111] In other examples, the main member 110 and the additional part 180 may not have the same geometric shape, for example, the main member 110 may have a substantially U-shaped cross section and the additional part 180 may be a substantially flat plate that closes the U-shaped cross section, and in these cases the flange may be subjected to a specific heat treatment that is different from the rest of the main soft zone.

[0112] 7 schematically illustrates a further example of a structural component 100 for a vehicle, the structural component 100 being at least partially configured to support a compressive load. In this example, the structural component 100 is a front rail, although other vehicle components such as door rings, rear rails, rear frames, rockers, one-piece floors, cross members, front upper rails, and chassis extensions, among others, may also be exemplary of the present disclosure.

[0113] 7, the compressive impact can be received by the main member 110 on the right side. In this case, the right side in FIG.

[0114] The introduction of portions 120, 130, 140 having lower mechanical properties, i.e., lower tensile strength, than the rest of the main member 110 allows deformation of the main member 110 to begin near where the impact occurs, rather than in any other area. Note that the transition zone 150 shown in Figures 3 and 4 is not shown in this figure for simplicity.

[0115] Varying the mechanical properties of the sections can facilitate control of the deformation of the main member 110, particularly where the deformation begins. Thus, if the first section 120, which has the lowest mechanical properties, is positioned closest to the point of compressive impact, the main member will begin to deform from this region.

[0116] 7, the structural component 100 may further comprise a secondary soft zone spaced longitudinally from the primary soft zone 170. For example, a secondary soft zone having higher mechanical properties than the primary soft zone 170 may be located further from the load-bearing end 111 to promote a second deformation point.

[0117] In some examples, ribs may be included in the main member 110 to further increase the strength differential between portions of the main member 110. Indeed, the characteristics of the ribs, including their number, shape, size, location, and extension across the main member 110, can be tailored to tailor the behavior of the structural component 100 when subjected to compressive loads. The ribs create stiffer, more rigid regions in the structural component 100. In this way, the behavior of the main member 110 and the structural component 100 can be better controlled in a crash.

[0118] 8 schematically illustrates another example of a structural component 100 for a vehicle framework, the structural component being at least partially configured to support a compressive load. In this example, the structural component 100 is a vehicle floor. In this particular example, the floor is a one-piece floor formed from a single, integrally formed component incorporating, for example, a sheet cross beam and a tunnel. The one-piece floor can be formed in a single press-hardening process.

[0119] In Figure 8, the direction of travel of the vehicle is from left to right. The longitudinal direction of the floor within the meaning of the independent claims is vertical in Figure 8. The floor in this example is designed and manufactured to have softer zones designed to absorb energy in the case of a lateral impact, i.e. an impact from the top or bottom in the example of Figure 8.

[0120] The floor in this example comprises a primary soft zone 170 having two portions 120, 130 that have a lower yield strength and / or ultimate tensile strength than the remainder of the primary member 110. In particular, as can be seen in the example of Figure 8, the primary member 110 comprises a primary soft zone 170 located on a first side of the primary member 110 and a secondary soft zone 171 located on a second side of the primary member 110.

[0121] The two portions 120, 130 of each of the primary and secondary soft zones 170, 171 are configured to be more ductile than the remaining harder portions of the main member 110. In particular, the two portions 120, 130 may have a higher elongation to break and / or an increased reduction in area before break.

[0122] In the example of FIG. 8, the first portion 120 is located closer to the load-bearing end of the main member 110 than the other portions 130 and may be the "softest" and most ductile portion.

[0123] The floor of a vehicle may experience a side impact at the load-bearing end 111. Because the first portion 120, which has the lowest mechanical properties, is located closest to the location experiencing the compressive impact, the main member 110 may begin to deform at the first portion 120 of the main soft zone 170, and subsequent portions from the load-bearing end, which have increasing strength, deform in a controlled manner. The floor can control the kinematics of the deformation and effectively absorb the impact energy while maintaining the interior space of the vehicle.

[0124] In the example of Figure 8, the primary soft zone tapers along its length (the direction in which it receives compressive loads in the event of a side impact). The primary soft zone reduces its width along its length. This allows for a balance between high strength (low weight) and energy absorption. Whether a lateral impact is received toward the front or rear of the vehicle, this arrangement allows deformation to be steered toward a more central area of ​​the floor.

[0125] 9 schematically illustrates a further example of a structural component 100 for a vehicle framework, the structural component being at least partially configured to support a compressive load. In this example, the structural component 100 is a vehicle door ring.

[0126] As shown in Figure 9, the door ring in this example extends from the A-pillar and hinge pillar to the B-pillar. Therefore, the door ring is a front door ring. In other examples, the door ring may be a complete door ring that extends from the A-pillar to the C-pillar.

[0127] The front door ring in this example includes a B-pillar portion, a rocker portion, a hinge portion, and an A-pillar portion. The door ring can be formed by joining different blanks to form a composite blank, and then forming the composite blank into an integrally formed door ring.

[0128] In this example, the vehicle rocker portion extending longitudinally from the load-bearing end 111 to the opposite end 112 includes a soft zone 170 .

[0129] Additionally, the door ring, and more particularly the rocker portion of the door ring, comprises a primary soft zone 170 having four portions 120 , 130 , 140 , 150 that have a lower yield strength and / or ultimate tensile strength than the remainder of the main member 110 .

[0130] The four sections 120, 130, 140, 150 may be more ductile than the remaining stiffer sections of the main member 110. In particular, the four sections 120, 130, 140, 150 may have a higher elongation to break and / or an increased reduction in area before break.

[0131] In the example of Figure 9, the four sections 120, 130, 140, 150 of the primary soft zone 170 are arranged along the length of the rocker portion of the floor. The first section 120, which is located closer to the load-bearing end of the primary member 110 than the other sections, is the "softest" and most ductile section. The second section 130 is adjacent to the first section 120, and the third section 140 is adjacent to the second section 130, and has a third mechanical property that is higher than the mechanical property of the first and second sections 120, 130, but lower than the mechanical property of the fourth section 150, which is located adjacent to the third section 140.

[0132] In some examples, the yield strength of first portion 120 may be 300 to 600 MPa, specifically 300 to 500 MPa, and the yield strength of second portion 130 may be 350 to 600 MPa, specifically 400 to 550 MPa. Furthermore, the yield strength of third portion 140 may be 600 to 850 MPa, specifically 650 to 800 MPa, and the yield strength of fourth portion 150 may be 700 to 100 MPa, specifically 750 to 950 MPa.

[0133] A vehicle door ring may be subjected to a frontal impact at the load-bearing end 111. Because the first portion 120, which has the lowest mechanical properties, is located closest to the location experiencing the compressive impact, the main member 110 may begin to deform at the first portion 120 of the main soft zone 170, and subsequent portions from the load-bearing end, which have increasing strength, may deform in a controlled manner. The door ring can control the kinematics of the deformation and effectively absorb the impact energy while maintaining the interior space of the vehicle.

[0134] In another aspect of the present invention, a method 200 is provided for manufacturing a structural component 100 configured at least in part to support a compressive load as described throughout this disclosure. Method 200 is illustrated generally in the block diagram of FIG.

[0135] The method 200 includes providing a primary blank at block 201. The method further includes at least partially heating the primary blank to a temperature above an austenitizing temperature at block 202, wherein adjacent first and second portions 120, 130 are heated differently than other portions of the primary blank.

[0136] The method 200 further includes, at block 203, press-hardening the heated primary blank to form a primary member of the structural component 100. The formed primary member 110 includes a primary soft zone 170 having a lower mechanical property than other zones of the primary member 110. The primary soft zone 170 further includes a first portion 120 with a substantially constant first mechanical property and a second portion 130 with a substantially constant second mechanical property. The first mechanical property is lower than the second mechanical property.

[0137] Additionally, the first portion 120 may be positioned closer to the load-receiving end 111 than the second portion 130 .

[0138] In an example where the primary blank forms a primary member 110 configured to be joined with an additional component 180, the method 200 can include heating (either before, during, or after deformation) a portion of the primary blank intended to contact the additional component 180 differently from other portions of the primary blank, so that the mechanical properties of this portion after forming are lower than the remainder of the primary member 110.

[0139] Additionally, the method 200 may be adapted to form a main member 110 having any combination of the aforementioned technical features.

[0140] The primary blank may be made from any type of hardenable steel, as previously described with respect to structural component 100 .

[0141] The heating step 202 of the method 200 may include substantially uniformly heating the primary blank at a temperature above the austenitizing temperature, and then cooling a portion of the primary blank specifically below the austenitizing temperature.

[0142] In an example, the primary blank may be heated above Ac3, and a portion of the primary blank may be cooled to a temperature below Ac3 or even below Ac1 before deforming the blank, while other portions may be maintained above Ac3 until the blank is deformed, or may be briefly cooled but then heated again above Ac3.

[0143] For example, during the first stage of heating step 202, the primary blank may be heated substantially uniformly above Ac3 in the main furnace. Then, in the second stage of step 202, a portion of the primary blank corresponding to the (formed) soft zone may be cooled to a temperature below Ac3, while other portions remain at a higher temperature, e.g., above Ac3. Additionally, in the third stage of step 202, the primary blank may be heated again while maintaining the portion corresponding to the soft zone below Ac3 and the remaining portion of the primary blank at a temperature above Ac3. The third stage of step 202 may function to raise the temperature of the remaining portion of the primary blank above Ac3 in situations where the overall temperature of the primary blank was reduced during the second stage. The three stages of step 202 may be performed in the same furnace or in separate facilities downstream from the main furnace.

[0144] In some examples, the heating step 202 of method 200 may include blowing air through nozzles against the portion of the primary blank being cooled. The nozzles may be distributed in an array or 2D matrix to provide a more precise temperature profile along and / or across the primary blank. This may be done in the same furnace in which the primary blank is heated, or in a separate facility downstream from the main furnace.

[0145] The inventors have found that this type of method, in which the heated blank is partially cooled by the pressurized nozzle, allows for cooling of specific portions of the blank with a significantly smaller effect on the temperature of the remainder of the blank. This type of method allows for precise control of the temperature profile of the heated main member and the resulting material microstructure along the structural part. Furthermore, this method represents a cost-effective approach for forming the structural parts of the present disclosure.

[0146] The cooling nozzles can establish a temperature difference of at least 100 degrees, and preferably at least 200 degrees, between at least a first portion 120 of the main member and the remainder of the main member 110. Additionally, multiple temperature differences between portions of the main member can be established. For example, it is possible to establish three or more portions 120, 130, 140 of the main member 110, each having a different temperature.

[0147] In one example, the portion of the blank that is to be fully hardened may remain at a temperature of 900°C or higher. The first portion may be reduced to a temperature lower than Ac1, for example, between 600°C and 700°C. The second portion 120 may have a higher temperature than the first portion but lower than the portion of the blank that is to be fully hardened. The temperature of the second portion may be, for example, between 700°C and 800°C.

[0148] Thus, the different temperatures may result in different microstructures or strength properties being set in the respective portions of the main member 110, particularly during any subsequent rapid cooling ("quenching"), such as during a hot stamping process.

[0149] In an example, the main member is formed during a press hardening step 203 to form the part and is simultaneously hardened to below 400°C, or specifically below 300°C.

[0150] In an example, the cooling nozzles can include at least one tangential nozzle. The tangential nozzle can propel compressed air with a directional component substantially parallel to the process plane, i.e., the surface of the part. The tangential nozzle propels compressed air at a non-zero angle relative to the surface of the part. For example, the tangential nozzle can be oriented so that the airflow from the tangential nozzle and a vector normal to the surface of the part form an angle of less than 30 degrees, more specifically less than 15 degrees.

[0151] The tangential nozzles can thus create a flow seal that can prevent air from other nozzles from reaching a given portion of the primary blank, and thus can be used to control temperature gradients along and / or across the primary blank.

[0152] In some examples, the cooling nozzles may be mounted on a moving frame that may be capable of displacing and rotating the individual nozzles relative to the main blank.

[0153] While only some examples are disclosed herein, other alternatives, modifications, uses, and / or equivalents thereof are possible. Accordingly, the scope of the disclosure should not be limited by the specific examples, but should be determined solely by a fair reading of the following claims.

Claims

1. A structural component (100) for a vehicle framework, said structural component being at least partially configured to support a compressive load; a main member (110) extending longitudinally from a load-bearing end (111) to an opposite end (112) of said main member (110); The primary member (110) includes a primary soft zone having lower mechanical properties than other zones of the primary member; the primary soft zone comprises a first portion (120) of a substantially constant first mechanical property and a second portion (130) of a substantially constant second mechanical property, the first mechanical property being lower than the second mechanical property; A structural component, wherein the mechanical properties are ultimate tensile strength and yield strength.

2. 2. The structural component (100) of claim 1, wherein the first portion (120) is positioned closer to the load-bearing end (111) than the second portion (130).

3. 3. The structural component (100) of claim 1 or 2, wherein the primary soft zone further comprises a third portion (140), the third portion (140) having a substantially constant third mechanical property that is higher than the second mechanical property.

4. 4. A structural component (100) according to any one of claims 1 to 3, wherein the portions (120, 130, 140) of the main soft zone are arranged along the longitudinal direction based on their mechanical properties, with portions having lower mechanical properties being closer to the load-bearing end (111) and portions having higher mechanical properties being further from the load-bearing end (111).

5. A structural component (100) according to any one of the preceding claims, wherein the primary soft zone is formed by subjecting the primary soft zone to a different temperature treatment than other zones of the primary member (110).

6. 6. The structural component (100) of any one of claims 1 to 5, further comprising a secondary soft zone spaced along the longitudinal direction from the primary soft zone and closer to the opposite end (112) of the main member.

7. The structural component (100) of claim 6, wherein the secondary soft zone has higher mechanical properties than the primary soft zone.

8. 8. The structural component (100) of any one of claims 1 to 7, wherein the main member (110) predominantly has an ultimate tensile strength of at least 1.000 MPa, particularly at least 1.200 MPa, more particularly at least 1.500 MPa.

9. 9. The structural component (100) of any one of claims 1 to 8, further comprising an additional component (180) configured to be coupled to the main member (110) at a flange (165, 116, 117), the flange (165, 116, 117) having lower mechanical properties than the main soft zone.

10. 10. The structural component (100) of any one of claims 1 to 9, wherein the local yield strength of each of the first and second portions (120, 130) varies by less than 15% around the average yield strength of the first and second portions (120, 130), respectively.

11. A structural component (100) according to any one of the preceding claims, wherein the difference between the average yield strengths of two adjacent portions (120, 130) is greater than 10%, in particular greater than 20%.

12. The structural component (100) of any one of claims 1 to 11, wherein the structural component (100) is or forms part of a door ring, a rear rail, a rear frame, a rocker, a floor component, a cross member, a shotgun, and a chassis extension.

13. A method (200) for manufacturing a structural component (100) for a vehicle framework, said method (200) comprising: Providing a primary blank (201); heating the primary blank at least partially to a temperature above the austenitizing temperature, wherein adjacent first and second portions are heated differently from other portions of the primary blank; press hardening (203) the heated primary blank to form a primary member of the structural component, the primary member including a primary soft zone having lower mechanical properties than other zones of the primary member; the primary soft zone comprises a first portion (120) of a substantially constant first mechanical property and a second portion (130) of a substantially constant second mechanical property, the first mechanical property being lower than the second mechanical property; The mechanical properties are ultimate tensile strength and yield strength.

14. 14. The method (200) of claim 13, wherein heating (202) the primary blank comprises substantially uniformly heating the primary blank at a temperature above the austenitizing temperature, and then cooling a portion of the primary blank, in particular at a temperature below the austenitizing temperature.

15. 15. The method (200) of claim 14, wherein cooling the portion of the primary blank comprises blowing pressurized air through a nozzle against the portion.

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