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 bending loads. The structural component comprises a main member (110) defining a substantially U-shaped cross-section with a bottom wall (113), a first side wall (114), and a second side wall (116). The main member (110) further comprises a main soft zone (170) having lower mechanical properties than other zones of the main member (110). The main soft zone (170) includes, at a given longitudinal position, a first soft portion (120) of substantially constant mechanical properties adjacent to a second soft portion (140) of substantially constant mechanical properties. The present disclosure further relates to a method for manufacturing such a structural component.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of EP22382875.7, filed September 22, 2022. [Technical Field]

[0002] The present disclosure relates to structural components for vehicle frameworks, the structural components being configured to at least partially support bending loads. The disclosure also relates to methods for manufacturing such structural components. [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 the pillars (A-pillar, B-pillar, C-pillar), integral door rings, rockers, floors, and weave lockers, can be specifically designed to support bending loads. That is, these sections are positioned to undergo bending loads in the event of a typical crash scenario. These and other structural components can 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] 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.

[0019] UHSS can exhibit tensile strengths as high as 1,500 MPa or even 2,000 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.

[0020] 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.

[0021] Although ductile steel allows for energy absorption by structural components, it can be difficult to control and predict how the structural components may behave during a vehicle crash. Furthermore, it is preferable that the overall weight of the vehicle framework be as low as possible to reduce fuel consumption. Also, it is difficult to improve energy absorption while maintaining a certain structural integrity of the structural components.

[0022] The present disclosure aims to provide controlled deformation of and improved energy absorption by structural components for vehicle frameworks when subjected to loads, particularly bending loads. Summary of the Invention

[0023] In a first aspect, a structural component for a vehicle framework is provided. The structural component is at least partially configured to support bending loads. The structural component includes a main member defining a substantially U-shaped cross-section along at least a portion of the main member, the U-shaped cross-section including a bottom wall, a first sidewall, a first outwardly extending side flange, a second sidewall, and a second outwardly extending side flange. The main member extends along the length of the main member from a first end to a second end. The main member includes a main soft zone extending between a first longitudinal position and a second longitudinal position, the main soft zone having lower mechanical properties than other zones of the main member. Further, the main soft zone includes a first soft portion with a substantially constant mechanical property and a second soft portion with a substantially constant second mechanical property. The first soft portion is disposed adjacent to the second soft portion at a longitudinal position between the first longitudinal position and the second longitudinal position, and the first soft portion has mechanical properties different from the mechanical properties of the second soft portion, and the mechanical properties are ultimate tensile strength and yield strength.

[0024] The introduction of a primary soft zone, including a first soft portion and a second soft portion having first and second mechanical properties, respectively, provides a primary member capable of effectively absorbing energy during a crash while controlling the kinematics of deformation. The extent to which the soft zone penetrates toward the interior of the vehicle can be controlled by differentiating the mechanical properties of the sides of the U-shaped cross section from the mechanical properties of the bottom of the U-shaped cross section.

[0025] Additionally, the soft portion may include side flanges that may be used for attachment to other components. By controlling the mechanical properties of these side flanges to a desired level, fractures or tears at the joints may be avoided, reduced, or better controlled.

[0026] The main members may be able to absorb more energy during bending with a high degree of deformation predictability, while the remaining main members with higher mechanical properties may provide limitations to deformation and maintain the interior space of the vehicle, thereby increasing the safety of the vehicle occupants.

[0027] A bending load may be understood as a load or component of a load that acts substantially perpendicular to the length of a structural part, tending to bend the part. Parts or areas within an automobile framework that may be particularly subject to bending loads include, for example, B-pillars, door rings, rear rails, rockers, and integral structures, including, for example, the floor or rear frame. Accordingly, the examples disclosed herein may be particularly beneficial when used with this type of part.

[0028] Throughout this disclosure, "at least partially configured to support bending loads" may be understood to mean that a portion of a component or the entire component is expected to primarily absorb bending loads in the event of an impact or collision, i.e., bending loads are expected to be higher, although other loads may also occur.

[0029] 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.

[0030] 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.

[0031] 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 sections, specimens made of the same material as the main soft zone section can be prepared and tested on a universal testing machine (UTM).

[0032] 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%.

[0033] "Next to" with respect to the soft portions of the soft zone can generally be interpreted as adjacent. It is obviously possible to form a (small) transition zone between two adjacent soft portions.

[0034] In some examples, the second flexible portion may be a bottom flexible portion at least partially disposed on the bottom wall, and the first flexible portion may be a side flexible portion at least partially disposed on the first and second side flanges and / or the first and second side walls.

[0035] In some examples, the mechanical properties of the bottom flexible portion may be lower than the mechanical properties of the side flexible portions. In these examples, the side flexible portions may limit the protrusion of the bottom of the U-shaped cross section upon impact. The lower mechanical properties of the bottom flexible portion may provide increased energy absorption.

[0036] In some examples, the second flexible portion may be disposed on the first side flange, and the first flexible portion may be disposed on the first sidewall. That is, in some of these cases, the flexible portion may be formed asymmetrically with respect to the cross section of the U-shape in that a flexible zone is provided on only one of the sides of the U-shape. In other examples, both sides of the U-shape may include a flexible zone.

[0037] Having a soft zone on only one side of the U-shape provides localized deformation to absorb energy in the event of an impact while limiting the potential deformation of the entire structure. Soft zones in the flange areas can further reduce localized tearing or cracking.

[0038] In an example, a primary soft zone in a structural component is formed by subjecting the primary soft zone to a different heat treatment than other zones of the primary member.

[0039] Additionally, in some instances, different portions of the primary soft zone may be subjected to different heat treatments, for example, the bottom wall may be subjected to a first heat treatment and the side wall may be subjected to a second heat treatment that is different from the first heat treatment, or different portions of the side wall may be subjected to different heat treatments.

[0040] In some examples, the yield strength of the second soft portion is 300 to 600 MPa, specifically 400 to 500 MPa, and the yield strength of the first soft portion is 600 to 950 MPa, specifically 650 to 800 MPa.

[0041] In some examples, the first and second side walls include first and second flanges extending outward from the respective side walls. The flanges may be used to connect the main member to other components of the vehicle. Additionally, the flanges may increase the member's resistance to bending deformation, i.e., the flanges may increase the main member's moment of inertia.

[0042] In an example, the second flexible portion is disposed on the bottom wall and at least a portion of the first and second side walls. Furthermore, the first flexible portion is disposed on the first and second flanges. In this manner, the bottom wall and portions of the side walls may have lower mechanical properties than the flanges. Therefore, these walls may deform first in the event of an impact, while the flanges may provide greater strength and substantially maintain the integrity of the main member.

[0043] In some examples, the main soft zone of the structural component may further include an intermediate soft portion of substantially constant (third) mechanical properties that substantially connects the first soft portion to the second soft portion. The third mechanical properties may be higher than the (second) mechanical properties of the second soft portion. In examples, the second soft portion may be located on a flange adjacent to the side wall, and the intermediate soft portion may be located on a portion of the side wall opposite the bottom wall.

[0044] In an example, the structural component may include a minor soft zone spaced longitudinally from the major soft zone and closer to the second end of the main member. The minor soft zone may be different from the major soft zone. For example, the minor soft zone may have higher mechanical properties than the major soft zone. In an example, the minor soft zone may include more or fewer portions with different mechanical properties than the major soft zone.

[0045] In some examples, the primary 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. The yield strength of the primary members outside the primary soft zones may be higher than the primary soft zones.

[0046] In some examples, the local mechanical properties of each of the first soft portion and the second soft portion vary by less than 15%, more particularly less than 10%, around the average value of the mechanical properties of the respective portions. The yield strength of a material represents the maximum stress it can withstand before it begins to permanently change shape, i.e., marks the limit of elastic behavior and the onset of plastic behavior when subjected to a load.

[0047] In some examples, the width of the transition zone between portions of the soft zone(s), i.e., between the first and second soft portions of the main soft zone, or between the main component and the soft zone(s), may be less than 30 mm, specifically between 20 mm and 5 mm, depending on manufacturing parameters such as the temperature difference between adjacent portions, or the manufacturing procedure.

[0048] 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%.

[0049] 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.

[0050] 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 first end to cross-sections further away.

[0051] 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.

[0052] 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.

[0053] 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 bending loads.

[0054] 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 bending loads of the main member resulting from, for example, a (simulated) impact or collision.

[0055] In an example, a structural component may include an additional component attached to a main component. The additional component may be, for example, a plate or cover attached to a flange of the main component. The additional component may also be of a similar size and shape to the main component, i.e., the structural component is formed by two similar components.

[0056] In some examples, the additional members may be made of the same material and by the same manufacturing process as the main member. In other examples, the additional members may be made of a different process and / or a different steel. In some examples, the additional members may be cold formed from a suitable cold formed steel.

[0057] In some examples, soft zone(s), including the first and second soft portions (and optionally further soft portions) described above, may also be formed in the additional component.

[0058] In a further aspect, a method is provided for manufacturing a structural component configured at least in part to support bending loads to obtain a structural component for a vehicle framework as described in this disclosure.

[0059] The method includes providing a primary blank. The method further includes heating the primary blank at least partially to a temperature above the austenitizing temperature, where the portion is heated differently from the remaining portion of the primary blank, and press-hardening the heated primary blank to form a primary member of a structural component. The formed primary member defines a substantially U-shaped cross-section along at least a portion of the primary member, the U-shaped cross-section including a bottom wall, a first sidewall, a first outwardly extending flange, a second sidewall, and a second outwardly extending flange. The primary member further includes a primary soft zone having lower mechanical properties than other zones of the primary member. The primary soft zone further extends from a first longitudinal position to a second longitudinal position and includes a first soft portion with substantially constant mechanical properties and a second soft portion with substantially constant mechanical properties. At a longitudinal position between the first and second longitudinal positions (i.e., within the main soft zone), the first soft portion is disposed adjacent to the second soft portion, and the mechanical properties of the first soft portion are different from the mechanical properties of the second soft portion.

[0060] The method can improve the deformation behavior of a structural component configured to support bending loads, for example, allowing for tailoring how the structural component deforms during a vehicle crash, thus enhancing energy absorption by the structural component.

[0061] 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.

[0062] 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 portions of the primary blank, in particular at a temperature below the austenitizing temperature. The portions that are cooled may be adjacent to each other, i.e., the edge of one portion touches the edge of an adjacent portion.

[0063] In some examples of the method, the cooling may include blowing air through a nozzle against the portion of the primary blank being cooled.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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]

[0070] 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 bending loads. [Figure 2] 10 is a schematic illustration of the post-quench yield strength of an example structural component as a function of lateral position; [Figure 3] 2 shows two cross sections of another example of a structural component diagrammatically. [Figure 4] 2A and 2B illustrate diagrammatically another example of a structural component for a vehicle configured at least in part to support bending loads. [Figure 5]2A and 2B illustrate schematic diagrams of further examples of structural components for vehicles that are at least partially configured to support bending loads; [Figure 6] 2A and 2B illustrate diagrammatically another example of a structural component for a vehicle configured at least in part to support bending loads. [Figure 7] 2A and 2B illustrate schematic diagrams of further examples of structural components for vehicles that are at least partially configured to support bending loads; [Figure 8a] 1A and 1B are schematic perspective views of another example of a structural component for a vehicle configured at least in part to support bending loads; [Figure 8b] 8b shows a schematic top view of the structural component shown in FIG. 8a. [Figure 8c] 8a-8b show schematic cross sections of the structural components shown in FIG. [Figure 9] 1 is a flowchart of a method for manufacturing a structural component configured at least in part to support bending loads.

[0071] 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

[0072] 1 schematically illustrates a structural component 100 for a vehicle configured, or at least partially configured, to support bending loads. The structural component 100 comprises a main member 110 defining a substantially U-shaped cross-section along at least a portion of the main member, the U-shaped cross-section comprising a bottom wall, a first side wall, and a second side wall.

[0073] The main member 110 extends from a first end 111 to a second end 112 along the length of the main member 110. The first end may be the bottom of the main member and the second end may be the top, or vice versa. The first end may be the front end (in the longitudinal direction of the vehicle) and the second end may be the rear end (in the longitudinal direction of the vehicle), or vice versa. If the part is mounted generally along the lateral direction of the vehicle, the first end may be, for example, the left end and the second end may be the right end, or vice versa.

[0074] The primary member 110 includes a primary soft zone 170 that has lower mechanical properties than other zones of the primary member 110. The primary soft zone 170 extends from a first longitudinal location (closer to the first end) to a second longitudinal location (closer to the second end).

[0075] Furthermore, the main soft zone 170 comprises a first soft portion 120 of substantially constant (first) mechanical properties and a second soft portion 140 of substantially constant (second) mechanical properties. At longitudinal positions between the first and second longitudinal positions, i.e., at longitudinal positions within the main soft zone, the first soft portion 120 is disposed next to the second soft portion 140. In an example, the first soft portion 120 may be subjected to a first heat treatment, and the second soft portion 140 may be subjected to a second heat treatment. Furthermore, the difference between the first and second heat treatments may result in the first soft portion 120 having a different material microstructure than the second soft portion 140.

[0076] Furthermore, the second mechanical property (of the second soft portion) may be lower than the first mechanical property (of the first soft portion), which may be beneficial in limiting the degree of penetration in the event of an impact.

[0077] For example, in the case of a B-pillar, the main soft zone may be located in the lower half of the B-pillar, specifically in the bottom 40% of the B-pillar. The main soft zone in the B-pillar is generally provided to be able to absorb energy in the event of a side impact. The location of the soft zone determines how the B-pillar deforms, and the main soft zone may particularly form a hinge-like portion, the main soft zone being an area of ​​the B-pillar that generally protrudes more inward than other portions of the B-pillar in the event of an impact. Providing a first soft portion with higher mechanical properties (i.e., higher yield strength and / or ultimate tensile strength) than a second soft portion may enable energy absorption while at the same time limiting inward intrusion in the event of a crash, thus improving occupant safety.

[0078] As shown in FIG. 1, the main soft zone 170 of the main member 110 may further include an intermediate soft portion 130 of substantially constant (third) mechanical properties.

[0079] In this illustrated example, the first flexible portion 120 may be disposed on a portion of the first and second side flanges, and the intermediate flexible portion 130 may be disposed on a portion of the first and second side walls 114 and 115, i.e., perpendicular to the centerline C. Additionally, the third mechanical property may be lower than the second mechanical property.

[0080] Thus, the main member 110 may include a main soft zone 170 that includes two or more distinct portions with respect to mechanical properties, one adjacent to the other. The portions 120, 140, 130 may be arranged based on mechanical properties, i.e., the portion with the lowest mechanical properties at the bottom wall and the portion with the highest mechanical properties furthest from the bottom wall 113, particularly at one or both of the side flanges.

[0081] Throughout this disclosure, portions of the soft zone are shown on one side of the structural member 100, but it should be understood that any type of soft zone shown may, but need not, be symmetrical about the centerline C of the structural member 100.

[0082] The main member 110 of the structural component 100 in the example of FIG. 1 outside the main soft zone 170 may primarily have an ultimate tensile strength of 1.000 MPa or greater, specifically 1.200 MPa or greater, and more specifically 1.500 MPa or greater.

[0083] In an example, the second soft portion 140 may have a yield strength between 300 and 600 MPa, specifically between 400 and 500 MPa (e.g., an average of about 450 MPa). In an example, the yield strength of the first soft portion is 600 to 950 MPa, specifically between 650 and 800 MPa (e.g., an average of about 725 MPa). The yield strength of the main member outside the main soft zone may be (mainly) higher than 1,000 MPa.

[0084] Additionally, the structural component 100 has a bottom wall 113 that can be substantially perpendicular to the first side wall 114 and the second side wall 115 (easily visible in FIG. 3). In a further example, the bottom wall 113 may define an angle other than 90 degrees relative to the first side wall 114 and the second side wall 115.

[0085] 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, i.e., the mechanical properties of the materials used, the desired maximum local strength, etc.

[0086] 3 , the structural component 110 can include first and second side flanges 116, 117 extending outwardly from the first and second side walls 114, 115, respectively. The flanges 116, 117 provide convenient attachment points, for example, for riveting or spot welding, to connect the structural component 100 to other components of the vehicle, such as other components of the vehicle's structural framework. The radii of curvature between the first and second side walls 114, 115 and the flanges 116, 117 can also vary according to the specifications of the structural component 110, as previously discussed.

[0087] In an example, a portion of the main flexible zone 170 , i.e., the first flexible portion 120 or the intermediate flexible portion 130 , may be located substantially at the first flange 116 and the second flange 117 .

[0088] The main member 110 may have a transition zone 150, i.e., a transition zone between different portions of the main soft zone 170 or between the main soft zone and a harder zone of the main member 110, having a width of less than 30 mm, specifically between 20 mm and 5 mm.

[0089] 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® is commercially available from ArcelorMittal.

[0090] 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.

[0091] 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

[0092] Usibor® 2000 is another boron steel, 37MnB5, that has even higher strength. After the hot stamping die quench process, Usibor® 2000's yield strength can be 1300 MPa or greater, and its ultimate tensile strength can be greater than 1800 MPa.

[0093] 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

[0094] 22MnB5 and other boron steels may be coated with an aluminum-silicon coating to prevent decarburization and scale formation during the forming process.

[0095] Several 22MnB5 steels with similar chemical compositions are commercially available. However, the exact amounts of each component in 22MnB5 steel may vary slightly depending on the manufacturer. Other ultra-high strength steels include BTR 165, available from Benteler.

[0096] 2 is a simplified graph showing the average yield strength of the soft zone 170 of the structural component 100 along a transverse direction perpendicular to the longitudinal direction (the centerline along the longitudinal direction is shown in FIG. 1). The horizontal axis represents the transverse position across the structural component 100 from the centerline C in FIG. 1 to the end of the flange 116. The longitudinal axis represents the average yield strength of a given cross section after the structural component has been quenched, i.e., press hardened and at room temperature.

[0097] Note that the reference numbers in Figure 2 are associated with features in Figure 1. Thus, the area of ​​the graph with a given reference number refers to the yield strength of the corresponding feature in Figure 1, rather than the feature itself.

[0098] For materials used in 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, yield strength and ultimate tensile strength increase as ductility decreases, and vice versa.

[0099] 2 thus shows that the yield strength in the bottom wall 113, i.e., second soft portion 140, is relatively low and fairly constant. The yield strength of the main member 110 then increases (and therefore ductility decreases) in the first transition zone 150 to the higher level of yield strength of the intermediate soft portion 130. This change in mechanical properties occurs over a relatively short width, for example, on the order of up to 20 mm. After this first transition zone 150, the main soft zone 170 comprises the first soft portion 120, which has higher strength and lower ductility compared to the second soft portion 140 and the intermediate portion 130.

[0100] The local yield strength of the soft zones is higher in the second transition zone 150 after the intermediate soft portion 130. The third plateau after the second transition zone 150 corresponds to the first soft portion 120, and the mechanical properties are higher within the soft zone 170. As can be seen in Figure 2, the yield strength gradients in the different transition zones 150 can be different.

[0101] 2 does not include specific values ​​for strength or location, as it serves merely as an example of the present disclosure. Also, while the width of some of the transition zones 150 may appear relatively large compared to the length of portions of the primary soft zone 170, this is done explicitly to illustrate potential differences in yield strength gradients. The microstructure that can be obtained can be controlled by appropriate heat treatment.

[0102] The difference in average yield strength between two adjacent portions 120-130, 130-140 may be greater than 10%, specifically greater than 15%, or even greater than 20%. In some examples, the difference between the average yield strength of two adjacent portions may not be the same as the difference between any two 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%.

[0103] Figure 3 shows two cross sections of an example structural component diagrammatically. These and other cross sections may be part of the same structural component, i.e., the structural component may have a cross section that varies along its length, or they may be cross sections from different structural components.

[0104] Although not shown in the example of FIG. 3 , 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 of the first sidewall 114 and / or the second sidewall 115 along their longitudinal direction 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.

[0105] 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.

[0106] As shown in Figure 3, the transition zone 150 between a first flexible portion and another flexible portion (an intermediate flexible portion or a second flexible portion) can be located at different points along the lateral direction of the main member 110. For example, the transition zone 150 in the first cross section (left view) is relatively close to the flanges 116, 117, while the transition zone 150 in the second cross section (right view) is relatively close to the bottom wall 113. The transition zone 150 may be located less than 20% of the height of the side wall in the example on the left side of Figure 3. The location of the transition zone 150 can be established so that a particular kinematics of the structural component is achieved after bending impact.

[0107] 4 schematically illustrates another example of a structural component 100 for a vehicle, the structural component being configured, or at least partially configured, to support bending loads. In this example, a primary member 110 includes a primary soft zone 170 having a lower yield strength and / or ultimate tensile strength than the remainder of the primary member 110. The primary soft zone in this example includes a first soft portion 120 and a second soft portion 140 separated by a transition zone 150 near a first flange 116 and a second flange 117. The two portions 120, 140 may be more ductile than the remaining, harder portions of the primary member. In particular, the two portions may have a higher elongation to break and / or an increased reduction in area before break, i.e., they may be more ductile than the remainder of the primary member 110.

[0108] Additionally, the two portions 120, 140 have different mechanical properties. Other numbers of portions, i.e., four or more, as well as other relative sizes, may be included in a structural component 100 according to the present disclosure.

[0109] In the illustrated example, the local yield strength of each portion 120, 140 may vary by less than 15% about the average yield strength of the respective portion, i.e., the yield strength and / or ultimate tensile strength may be substantially constant within each portion 120, 140.

[0110] 4, 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.

[0111] The structural component 100 includes an additional member 180 attached to the main member 110. The additional member 180 may be a cover or a plate. The additional member 180 may be attached to the first side flange 116 and the second side flange 117. The additional member 180 may also include a soft zone at the same longitudinal location where the main soft zone 170 is formed in the main member 110. In other examples, the additional member does not have a soft zone. In some examples, the steel of the additional member 180 may be different from the steel of the member 110 (e.g., cold-formed steel).

[0112] In another example not shown, the additional member may also have a U-shaped cross section similar to the main member 110 .

[0113] 5 shows a further example of a structural component for a vehicle, the component being at least partially configured to support bending loads. In this example, the structural component 100 is a B-pillar, although other vehicle components such as door rings, rear rails, and rockers, among others, may also be exemplary of the present disclosure. Large structural components of a vehicle, such as integrated structures including the floor or rear frame, may have portions of the component designed to support bending loads and other portions of the component designed to support other types of loads, i.e., compressive loads.

[0114] In Figure 5, bending impacts can be received perpendicular to the longitudinal direction of the main member 110. The main member 110 is a B-pillar, in particular a "center" B-pillar, or a load-bearing member of the B-pillar. A complete B-pillar may include, for example, an additional inner cover and an additional outer cover.

[0115] By introducing a soft zone 170 having portions 120, 140 with lower mechanical properties, i.e., lower tensile strength and yield strength, than the rest of the main member 110, deformation of the main member 110 may initiate and be concentrated in that portion rather than in any other region.

[0116] The main soft zone 170 in the B-pillar 100 may be located less than 50% of the height of the B-pillar, specifically less than 33% of the height of the B-pillar. The main soft zone may have a width of at least 5 cm, specifically at least 10 cm. The bottom of the B-pillar 100 may be rigid.

[0117] 5, the structural component 100 may further include a secondary soft zone 171 spaced longitudinally from the primary soft zone 170. For example, the secondary soft zone 171 may have different mechanical properties than the primary soft zone 170.

[0118] In an example, the secondary soft zone 171 may have higher mechanical properties than the primary soft zone 170 and may be located near the second end 112 to promote the second deformation point. The secondary soft zone 171 may include three or more portions 121, 131, as described above for the primary soft zone 170. In an example, the transition zone(s) 150 between the two or more portions 121, 141 may be located at a different lateral position than the primary soft zone 170.

[0119] 6 shows a schematic representation of another example of a structural component 100 for a vehicle framework, the structural component being at least partially configured to support bending loads. In this example, the structural component 100 is a single door ring for the vehicle. The door ring may be a front door ring, a rear door ring, or a double door ring.

[0120] The front door rings extend from the hinge pillars and A-pillars to the B-pillars, with a rocker section connecting the B-pillar to the hinge pillar. The rear door rings extend from the B-pillars to the C-pillars, and are connected to each other by a rocker section and a roof beam section.

[0121] In this example, the double door ring includes a B-pillar portion, a rocker portion, a hinge portion, an A-pillar portion, and a C-pillar portion. The double door ring may be formed by joining different blanks to form a combined blank and then forming the combined blank into a one-piece double door ring.

[0122] The main member 110 in this example comprises a door ring. The main member 110 comprises a major soft zone 170 and a minor soft zone 171 with three portions 120, 130, 140 having lower yield strength and / or ultimate tensile strength than the remainder of the main member 110. The three portions 120, 130, 140 may be more ductile than the remaining harder portions of the main member 110. Specifically, the three portions 120, 130, 140 may have a higher elongation to break and / or an increased reduction in area before break.

[0123] In another example, the structural component may be a front door ring or a rear door ring. The front and rear door rings may comprise a main member including a primary soft zone. In a further example, the front door ring and / or the rear door ring may further comprise a secondary soft zone.

[0124] The main soft zone 170 may be located partially in the B-pillar portion 100 and partially in the rocker portion of the main member. In the B-pillar portion 100, the main soft zone 170 may be located less than 50% of the height of the B-pillar portion, specifically less than 33% of the height of the B-pillar portion. The B-pillar portion 100 extends along a longitudinal (substantially vertical) direction and has a substantially U-shaped cross-section. The rocker portion of the main member also has a substantially U-shaped cross-section and extends along a substantially horizontal direction.

[0125] In particular, as can be seen in the example of FIG. 6, the main member 110 may comprise a main flexible zone 170 located on a first side wall and flange of the U-shape of the main member 110, and a secondary flexible zone 171 located on a second side wall and second flange of the main member 110.

[0126] 6, the three portions 120, 130, 140 of the primary soft zone 170 and the secondary soft zone 171 are arranged substantially symmetrically about the U-shape. The second soft portion 140 in each of these soft zones is arranged on the first and second side flanges, and the intermediate soft portion 130 and the first soft portion 120 are arranged on the first and second side walls.

[0127] In this example, the yield strength of the second soft portion 140 may be 300 to 600 MPa, specifically 300 to 500 MPa, the yield strength of the first soft portion 120 may be 600 to 950 MPa, specifically 650 to 800 MPa, and the yield strength of the intermediate portion 130 may be 300 to 500 MPa, specifically 400 to 500 MPa.

[0128] A vehicle door ring may be subjected to a bending impact perpendicular to the longitudinal direction of the main member 110. The door ring can effectively absorb the bending impact energy while controlling the kinematics of deformation and maintaining the interior space of the vehicle.

[0129] FIG. 7 illustrates, in schematic form, a further example of a one-piece double door ring for a vehicle that is at least partially configured to support bending loads.

[0130] 7, the main member 110 may comprise a rocker portion of a double door ring. The main member 110 may comprise a main flexible zone 170 located at the top of the rocker portion, i.e., at the first sidewall and first flange of the main member 110. The main member 110 may further comprise a secondary flexible zone 171 located at the top of the rocker portion.

[0131] Similar to the main member of Figure 6, the main soft zone 170 of the example member of Figure 7 includes three sections 120, 130, 140 of different mechanical properties. The three sections 120, 130, 140 are arranged along the same longitudinal direction of the main member 110. The second soft section 140 is arranged on the first flange, specifically the top flange of the rocker. The intermediate soft section 130 and the first soft section 120 are arranged on the top sidewall of the rocker.

[0132] 8a and 8b schematically illustrate perspective and top views of another example structural component 100 for a vehicle framework, the structural component being at least partially configured to support bending loads. The structural component 100 may be a tubular stiffener for the vehicle. In this example, the structural component 100 is a stiffener for a rocker of the vehicle.

[0133] In some examples, the vehicle rocker may be formed by a main member having a generally substantially U-shaped cross section and an additional member attached to the main member, and the main member and the additional member may be configured to form a closed volume when assembled together, with the tubular stiffener being positioned within the closed volume of the vehicle rocker. Many different rocker configurations are possible, and a rocker having a closed cross section may be provided within which the stiffener is positioned.

[0134] The rocker stiffener comprises a main member 110 that defines a substantially U-shaped cross section. The rocker stiffener also comprises an additional member attached to the main member 110 such that the main member and the additional member together form a closed cross section. The additional member may be a cover or a plate.

[0135] Additionally, Figure 8c shows a cross section of the rocker reinforcement shown in Figures 8a and 8b.

[0136] As shown schematically in Figures 8b and 8c, the rocker stiffener may comprise a primary soft zone 170 and a secondary soft zone 171 located on a first side wall and a second side wall of the U-shaped cross section of the rocker stiffener.

[0137] The main member 110 comprises a first soft portion 120 having a first mechanical property, a second soft portion 125 having a second mechanical property, and an intermediate soft portion 130 having a third mechanical property. The first soft portion 120, the second soft portion 140, and the intermediate soft portion 130 are arranged along the same longitudinal direction of the main member 110. In this example, the soft portions extend from the first end 111 of the main member 110 to the second end 112 of the main member, i.e., the main soft portion extends along the entire longitudinal length of the main member 110.

[0138] 8b and 8c, the first soft portion 120 and the second soft portion 125 have the same mechanical properties. The mechanical properties of the intermediate soft portion 130 are different from the mechanical properties of the first soft portion 120 and the second soft portion 140.

[0139] In this example, the yield strength of the first soft portion 120 and the second soft portion 125 may be 600 to 950 MPa, specifically 650 to 800 MPa, and the yield strength of the intermediate portion 130 may be 300 to 500 MPa, specifically 400 to 500 MPa.

[0140] The rocker reinforcement of Figures 8a-8c can effectively absorb bending impact energy while controlling deformation kinematics and maintaining the interior space of the vehicle.

[0141] 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 bending 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.

[0142] In another aspect of the present disclosure, a method 200 is provided for manufacturing a structural component 100 at least partially configured to support bending loads as described throughout this disclosure. Any of the structural components provided herein may be manufactured according to examples of such a method.

[0143] The method includes providing a primary blank at block 201. The method further includes at least partially heating the primary blank to a temperature above the austenitizing temperature at block 202, wherein adjacent first soft portion 120 and second soft portion 140 are heated differently from other portions of the primary blank.

[0144] The method further includes, at block 203, press-hardening the heated primary blank to form a primary member of structural component 100. The formed primary member 110 defines a substantially U-shaped cross-section including a bottom wall 113, a first side wall 114, a first side flange extending outwardly from first side wall 114, and a second side wall 115 with a second side flange extending outwardly.

[0145] Furthermore, the main member 110 comprises a main soft zone 170 having lower mechanical properties than other zones of the main member 110. Additionally, the main soft zone 170 comprises a bottom soft portion 120 of a substantially constant first mechanical property and side soft portions 140 of a substantially constant second mechanical property.

[0146] Within the flexible zone, at a given longitudinal position, the bottom flexible portion 120 is disposed at least on the bottom wall 113, and the side flexible portion 140 is disposed at least partially on the first side wall 114 and the second side wall 115 or the first side flange and the second side flange.

[0147] In an example, as described above, the first mechanical property of the bottom soft zone is lower than the second mechanical property of the side soft portions. Within the different soft portions, the mechanical property may be substantially constant.

[0148] Additionally, the method 200 may be adapted to form the main member 110 using any combination of the aforementioned technical features.

[0149] The primary blank can be made of any type of hardenable steel, particularly boron steel, as previously described with respect to the structural component 100 .

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] The cooling nozzles can establish a temperature difference of at least 100 degrees, specifically at least 200 degrees, between at least the bottom soft 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, 140, 130 of the main member 110, each having a different temperature.

[0156] In one example, the portion of the blank that is to be fully hardened (most or all of the area outside the main soft zone) may remain at a temperature above 900°C. The bottom soft portion may be reduced to a temperature below Ac1, for example, between 600°C and 700°C. The side soft portions 120 may have a higher temperature than the bottom soft portion but lower than the portion of the blank that is to be fully hardened. The temperature of the side soft portions may be, for example, 700-800°C. The temperature of one portion of the blank may be reduced while another portion is maintained above the austenitizing temperature, for example, above 900°C.

[0157] In some instances, cooling can be reduced to a lower range than described above and then reheated at least to some extent. When the blank is placed in the press tool, different portions of the blank can have different temperatures, but the temperature within these locations is substantially constant.

[0158] 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 subsequent rapid cooling ("hardening"), for example in the die of a press tool.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] While only a few examples are disclosed herein, other alternatives, modifications, uses, and / or equivalents thereof are possible. Moreover, all possible combinations of the described examples are also covered. Therefore, the scope of the present 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 bending loads; a main member (110) extending from a first longitudinal position to a second longitudinal position, the main member (110) defining a substantially U-shaped cross-section along at least a portion of said main member, said U-shaped cross-section comprising a bottom wall (113), a first side wall (114) having an outwardly extending first side flange, a second side wall (116), and a second outwardly extending side flange; The main member (110) extends from a first end (111) to a second end (112) along the length of the main member (110); the main member (110) comprises a main soft zone (170) having lower mechanical properties than other zones of the main member (110); said main soft zone (170) comprising a first soft portion (120) of substantially constant mechanical properties and a second soft portion (140) of substantially constant second mechanical properties; At a longitudinal position between the first longitudinal position and the second longitudinal position, the first flexible portion (120) is disposed adjacent to the second flexible portion (140); the mechanical properties of the first soft portion (120) are different from the mechanical properties of the second soft portion (140); A structural component, wherein the mechanical properties are ultimate tensile strength and yield strength.

2. The structural component (100) of claim 1, wherein the mechanical properties of the second soft portion (140) are lower than the mechanical properties of the first soft portion (120).

3. 3. The structural component (100) of claim 2, wherein the second soft portion (140) has a yield strength of 300 to 600 MPa, specifically 400 to 500 MPa, and the first soft portion (120) has a yield strength of 600 to 950 MPa, specifically 650 to 800 MPa.

4. 4. The structural component (100) of claim 1, wherein the primary soft zone (170) is formed by subjecting the primary soft zone (170) to a heat treatment that is different from other areas of the primary member (110).

5. 5. The structural component according to claim 1, wherein the second flexible portion (140) is a bottom flexible portion at least partially disposed on the bottom wall (113), and the first flexible portion (120) is a side flexible portion at least partially disposed on the first and second side flanges and / or the first and second side walls.

6. 6. The structural component (100) of claim 5, wherein the bottom soft portion (120) is disposed on the bottom wall (113) and at least a portion of the first side wall and / or the second side wall (114, 115).

7. 7. A structural component (100) according to claim 5 or 6, wherein the soft side portions are arranged on the first and second side flanges and at least partially on the first and / or second side walls (114, 115).

8. The structural component of any one of claims 1 to 4, wherein the second flexible portion (140) is disposed on the first side flange and the first flexible portion (120) is disposed on the first side wall.

9. The structural component of claim 8, wherein the primary soft zone (170) does not extend into a bottom of the U-shaped cross section.

10. 10. A structural component (100) according to any one of claims 1 to 9, wherein, at said longitudinal position, said main soft zone (170) comprises an intermediate soft portion (130) of substantially constant mechanical properties, which substantially connects said first soft portion (120) to said second soft portion (140).

11. A structural component (100) according to any one of the preceding claims, wherein the main member (110) outside the main soft zone predominantly has an ultimate tensile strength of 1.200 MPa or more, more particularly 1.500 MPa or more.

12. 12. A structural component (100) according to any one of claims 1 to 11, wherein the local yield strength of each of the first soft portion and the second soft portion (120, 140) varies by less than 15% around the average yield strength of the first soft portion and the second soft portion (120, 140), respectively.

13. A structural component (100) according to any one of claims 1 to 12, wherein the difference between the average yield strength of the first soft portion (120) and the average yield strength of the second soft portion (140) is greater than 10%, in particular greater than 20%.

14. A structural component (100) according to any one of the preceding claims, further comprising an additional member (180) attached to the main member (110).

15. The structural component of claim 14, wherein the additional member (180) includes a soft zone at a longitudinal location between the first longitudinal location and the second longitudinal location.

16. The structural component (100) of any one of claims 1 to 15, wherein the structural component (100) is or forms part of any of an integrated structure including a B-pillar, a door ring, a rear rail, a rocker, and a floor or rear frame.

17. 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 portions (120, 140) of the primary blank are heated differently from other portions of the primary blank; press-hardening (203) the heated primary blank to form a primary member (110) of the structural component (100), the primary member (110) defining a substantially U-shaped cross-section along at least a portion of the primary member, the U-shaped cross-section including a bottom wall (113), a first side wall, a first outwardly extending side flange, a second side wall (114, 115), and a second outwardly extending side flange, the primary member including a primary soft zone (170) having lower mechanical properties than other zones of the primary member (110); said main soft zone (170) extends from a first longitudinal position to a second longitudinal position and comprises a first soft portion (120) of substantially constant mechanical properties and a second soft portion (140) of substantially constant mechanical properties; At a longitudinal position between the first longitudinal position and the second longitudinal position, the first flexible portion (120) is disposed adjacent to the second flexible portion (140); A method wherein the mechanical properties of the first soft portion (120) are different from the mechanical properties of the second soft portion (140).

18. 18. The method (200) of claim 17, wherein heating (202) the primary blank comprises substantially uniformly heating the primary blank to a temperature above the austenitizing temperature, and thereafter cooling a portion of the primary blank, in particular to a temperature below the austenitizing temperature.

19. 20. The method (200) of claim 18, wherein cooling the portion of the primary blank comprises blowing pressurized air through a nozzle against the portion.

20. The method (200) according to any one of claims 17 to 19, wherein the structural component is a component according to any one of claims 1 to 16.

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