Structural component for a vehicle and method

Abstract

The present disclosure relates to a structural component for a vehicle frame at least partially configured for supporting a bending load. The structural component includes a main member (110) defining a generally U-shaped cross-section including a bottom wall (113), a first side wall (114), and a second side wall (116). Further, the main member (110) includes a main soft zone (170) having a lower mechanical property than other zones of the main member (110). The main soft zone (170) includes, at a given longitudinal position, a first soft portion (120) having a substantially constant mechanical property proximate to a second soft portion (140) having a substantially constant mechanical property. The present disclosure further relates to a method for manufacturing such a structural component.

Description

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

[0002] The present disclosure relates to a structural component for a vehicle frame, which is at least partially configured to support bending loads. The present disclosure further relates to a method for manufacturing such a structural component. Background Art

[0003] Vehicles such as automobiles include a structural framework designed to withstand the loads that the vehicle may be subjected to during its service life. The structural framework is further designed to withstand and absorb impacts in the event of, for example, a collision with other automobiles or road structures.

[0004] The need for weight reduction 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 need for weight reduction is particularly driven by the goal of reducing carbon dioxide emissions. The increasing concern for occupant safety has also led to the adoption of materials that improve the integrity of the vehicle during a collision while increasing the energy absorption rate.

[0005] A process called hot forming die quenching (HFDQ) typically uses boron steel sheets to produce stamped parts with ultra-high strength steel (UHSS) properties, such as a tensile strength of, for example, 1,500 MPa or 2,000 MPa, or even higher. The increase in strength allows the use of thinner gauge materials, which results in a weight reduction compared to traditional cold-stamped low-carbon steel parts. Throughout the present disclosure, UHSS can be considered a steel having an ultimate tensile strength of 1,000 MPa or more after a press hardening process.

[0006] In the HFDQ process, the blank to be hot formed can be heated to a predetermined temperature, such as the austenitization temperature or a higher temperature (especially a temperature between Ac3 and, for example, the evaporation temperature of the coating of the blank). A furnace system can be used for this purpose. Depending on the specific requirements, the furnace system can be equipped with additional heaters, such as induction heaters or infrared heaters. By heating the blank, the strength of the blank is reduced, and the deformability increases, i.e., to facilitate the hot stamping process.

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

[0008] Hot forming die quenching can also be referred to as "press hardening" or "hot stamping". These terms will be used interchangeably throughout the present disclosure.

[0009] Typical vehicle components that can be manufactured using the HFDQ process include: door cross-members, bumper cross-members, lateral / side members, A / B-pillar reinforcements, front and rear longitudinal beams, seat lateral members, and roof longitudinal beams.

[0010] Due to the excellent strength and formability of boron steel, its hot forming has become increasingly popular in the automotive industry. As a result, many structural components that were traditionally cold-formed from low-carbon steel are being replaced by hot-formed equivalents with significantly increased strength. This allows for a reduction in material thickness (and thus weight) while maintaining the same strength. However, the ductility and energy absorption rate of hot-formed components in the formed state are both at very low levels.

[0011] To increase the ductility and energy absorption rate of specific regions of a component, it is known to introduce softer regions within the same component. This increases ductility locally while maintaining the overall high strength required. By locally customizing the microstructure and mechanical properties of certain structural components to include regions with very high strength (very hard), i.e., regions with high ultimate tensile strength and high yield strength, and regions with increased ductility (softer), i.e., regions with lower ultimate tensile strength, lower yield strength, and increased elongation before fracture, the overall energy absorption rate of the component can be increased, its structural integrity can be maintained during a collision scenario, and its overall weight can also be reduced. In the case where the component fractures under impact, such soft regions can also advantageously alter the motion behavior.

[0012] Known methods for creating regions with increased ductility ("soft regions" or "soft zones") in the structural components of a vehicle include providing a tool comprising a pair of complementary upper and lower die units, each unit having a separate die element (steel block). The blank to be hot-formed is pre-heated to a predetermined temperature (e.g., the austenitizing temperature or higher) through, for example, a furnace system to reduce its strength, i.e., to facilitate the hot stamping process.

[0013] The die elements can be designed to operate at different temperatures to have different cooling rates in different regions of the part being formed during the quenching process, resulting in different material properties in the final product. For example, a soft region will typically have a lower ultimate tensile strength and a lower yield strength but allow for a greater elongation before fracture. For example, one die element can be cooled to quench the corresponding region of the part being manufactured at a high cooling rate, thereby rapidly reducing the temperature of the part and obtaining a hard martensitic microstructure. Another adjacent die element can be heated to ensure that the corresponding part of the part being manufactured cools at a lower cooling rate to obtain a softer microstructure, including, for example, bainite, ferrite, and / or pearlite. When the part exits the die, such regions of the part can remain at a higher temperature than the rest of the part.

[0014] Other methods for obtaining hot-stamped parts with regions of different mechanical properties include, for example, customized or differential heating prior to stamping and local heat treatment after the stamping process to alter the local microstructure and obtain different mechanical properties. Further possibilities include using patchwork blanks and tailor-welded blanks (TWBs), combining different thicknesses and / or materials in the blank.

[0015] Several methods of differential heating prior to stamping are known. In one example, for instance, when the blank is still in the oven, a nozzle or a group of nozzles can discharge a fluid stream, such as compressed cooling air, towards the part of the blank to be cooled. The other parts of the blank can be maintained at a higher temperature. This enables obtaining a blank with a customized temperature distribution along its length and / or width. In some examples, the blank can undergo further heating in the oven before being subjected to the stamping process.

[0016] In other examples, an infrared heater array can be used, which can be independently controlled to control the temperature along the blank.

[0017] Some elements of the vehicle's structural skeleton, such as pillars (A-pillar, B-pillar, C-pillar), integral door rings, sill panels, floor panels, and woven sill panels, can be specifically designed to support bending loads. That is, these parts are arranged such that they will be subjected to bending loads in the case of standard impact scenarios. These and other structural components can have one or more regions with a cross-section that is generally U-shaped (also known as "hat" shaped). These structural components can be manufactured in various ways and can be made of various materials. Lightweight materials that maintain the integrity of the vehicle while increasing the energy absorption during a collision are desirable.

[0018] In addition to the ultra-high-strength steels mentioned earlier, in parts of the structural skeleton where energy absorption is required, more ductile steels can also be used. Examples of ductile steels include 500, 1000 and CRL-340LA.

[0019] UHSS can exhibit a tensile strength of up to 1,500 MPa or even 2,000 MPa or more, especially after press hardening operations. Once hardened, UHSS will have a martensitic microstructure. This microstructure can increase the maximum tensile strength and yield strength per unit weight.

[0020] Some ductile steels can also be heated and pressed (i.e., used in a hot stamping process), but they will not have a martensitic microstructure after this process. Therefore, they will have a lower tensile strength and yield strength than UHSS, but they will have a higher elongation at break.

[0021] Although ductile steel can achieve energy absorption of structural components, it may not be easy to control and predict how the structural components behave during a vehicle collision. In addition, the overall weight of the vehicle frame is preferably as low as possible to reduce fuel consumption. Moreover, it is not easy to enhance energy absorption while maintaining a certain structural integrity of the structural components.

[0022] The present invention aims to improve the control of deformation and energy absorption of structural components for a vehicle frame when subjected to loads, especially bending loads. Summary of the Invention

[0023] In a first aspect, there is provided a structural component for a vehicle frame. The structural component is at least partially configured to support a bending load. The structural component includes a main member that defines a generally U-shaped cross-section along at least a portion of the main member. The U-shaped cross-section includes a bottom wall, a first side wall and an outwardly extending first side flange, a second side wall and an outwardly extending second side flange. The main member extends from a first end to a second end along a longitudinal direction of the main member. The main member includes a main soft zone that extends between a first longitudinal position and a second longitudinal position and has lower mechanical properties than other zones of the main member. Further, the main soft zone includes a first soft portion having generally constant mechanical properties and a second soft portion having generally constant second mechanical properties. At a longitudinal position between the first longitudinal position and the second longitudinal position, the first soft portion is disposed adjacent to the second soft portion. The mechanical properties of the first soft portion are different from the mechanical properties of the second soft portion. Further, the mechanical properties are ultimate tensile strength and yield strength.

[0024] Introducing the main soft zone including the first soft portion and the second soft portion having the first mechanical property and the second mechanical property respectively provides the main member with the ability to effectively absorb energy during a collision while controlling the deformation kinematics. The degree of intrusion of the soft zone towards the interior of the vehicle can be controlled by differentiating the mechanical properties of one side of the U-shaped cross-section from the mechanical properties of the bottom of the U-shaped cross-section.

[0025] And, the soft portions may include side flanges that can be used to attach other components. By controlling the mechanical properties of these side flanges to a desired level, fracture or tearing at the joints can be avoided, reduced or better controlled.

[0026] The main member can absorb more energy with a high degree of deformation predictability during bending. On the other hand, the remaining main member having higher mechanical properties can limit the deformation, saving the interior space of the vehicle. Thus, the safety of vehicle passengers can be enhanced.

[0027] A bending load can be understood as a load or load component that acts generally perpendicular to the length of a structural member in a manner that attempts to bend the member. Components or areas in a vehicle's frame that may be particularly subject to bending loads include: B-pillars, door rings, rear longitudinal beams, sill panels, and integrated structures such as a floor pan or rear frame. Thus, the examples disclosed herein will be particularly beneficial when used for such components.

[0028] Throughout this disclosure, "at least partially configured to support a bending load" can be understood to mean that a part or the whole of a component is expected to primarily absorb a bending load in the event of an impact or collision. That is, even if other loads may also occur, the bending load is expected to be higher.

[0029] Moreover, throughout this disclosure, a reference to "the mechanical properties of a part" can be understood to mean the mechanical properties of the material forming the part. Thus, unless otherwise stated, comparisons of the mechanical properties of various parts, components, or other portions are made with respect to the material, rather than its geometry or other characteristics.

[0030] In this document, higher mechanical properties can be understood to mean a higher ultimate tensile strength and / or a higher yield strength, while lower mechanical properties can be understood to mean a lower ultimate tensile strength and / or a lower yield strength. The ultimate tensile strength and the yield strength are considered herein as material properties of the material after the manufacturing process. The ultimate tensile strength and the yield strength can be determined in a standardized tensile strength test, for example, using A30, A50, or A80 specimens in a quasi-static load test.

[0031] The same test conditions and specimen sizes should be used for comparing lower and higher mechanical properties. To compare the yield strengths of different parts, specimens can be prepared from the same material as the parts of the main soft zone and tested in a universal testing machine (UTM).

[0032] Throughout this disclosure, a "part having generally constant mechanical properties" can be regarded as a part made of the same material that has been subjected to the same heat treatment. The resulting mechanical properties will be approximately the same as normal production tolerances. In each example, each part can have an average magnitude for mechanical properties such as hardness, yield strength, or ultimate tensile strength, and a local magnitude that deviates from the average magnitude by within ±15%.

[0033] The general arrangement of a soft part of a soft zone being "adjacent" can generally be regarded as being adjacent. It should be clear that a (small) transition zone may be formed between two adjacent soft parts.

[0034] In some examples, the second soft portion can be a bottom soft portion that is at least partially disposed at the bottom wall, and the first soft portion can be a side soft portion that is at least partially disposed in the first side flange and the second side flange and / or in the first side wall and the second side wall.

[0035] In various examples, the mechanical properties of the bottom soft portion can be lower than those of the side soft portion. In these examples, the side soft portion can limit the extrusion of the bottom portion of the U-shaped cross-section in the event of an impact. The lower mechanical properties at the bottom soft portion can provide increased energy absorption.

[0036] In some examples, the second soft portion can be disposed in the first side flange, and the first soft portion can be disposed in the first side wall. That is, in some of these cases, the soft portion can be shaped asymmetrically with respect to the U-shaped cross-section, where a soft zone is provided only in one of the sides of the U. In other examples, both sides of the U can include soft zones.

[0037] By providing a soft zone only on one side of the U, local deformation is provided in the event of an impact to absorb energy while limiting the potential deformation of the overall structure. The soft zone in the flange region can further reduce local tearing or cracking.

[0038] In various examples, the main soft zone of the structural member is formed by subjecting the main soft zone to a heat treatment different from that of other zones of the main member.

[0039] Further, in some examples, different portions of the main softening zone can be subjected to different heat treatments. For example, the bottom wall can be subjected to a first heat treatment, and the side walls can be subjected to a second heat treatment different from the first heat treatment, or different portions of the side walls can be subjected to different heat treatments.

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

[0041] In some examples, the first side wall and the second side wall include a first flange and a second flange that extend outward from the respective side walls. The flanges can be used to connect the main member to other components of the vehicle. Further, the flanges can increase the resistance of the member to bending deformation, that is, the flanges can increase the moment of inertia of the main member.

[0042] In each example, the second soft portion is disposed at least at a bottom wall and at least a portion of a first side wall and a second side wall. Further, the first soft portion is disposed at a first flange and a second flange. In this way, a portion of the bottom wall and the side walls can have mechanical properties lower than those of the flanges. Thus, these walls can deform first in the event of an impact, while the flanges can provide higher strength, thereby substantially maintaining the integrity of the main member.

[0043] In some examples, the main soft region of the structural member may further include an intermediate soft portion having substantially constant (third) mechanical properties that substantially connect the first soft portion to the second soft portion. The third mechanical property may be higher than the (second) mechanical property of the second soft portion. In each example, the second soft portion may be disposed at a flange adjacent to the side wall, and the intermediate soft portion may be disposed at a portion of the side wall opposite to the bottom wall.

[0044] In each example, the structural member may include a secondary soft region that is longitudinally spaced apart from the main soft region and closer to the second end of the main member. The secondary soft region may be different from the main soft region. For example, the secondary soft region may have higher mechanical properties than the main soft region. In each example, compared with the main soft region, the secondary soft region may include more or fewer portions having different mechanical properties.

[0045] In some examples, the ultimate tensile strength of the main member outside the (multiple) soft regions of the structural member is mainly 1.000 MPa or more, specifically 1.200 MPa or more, and more specifically 1.500 MPa or more. The yield strength of the main member outside the main soft region may be higher than the yield strength of the main soft region.

[0046] In some examples, the local mechanical property of each of the first soft portion and the second soft portion varies less than 15%, more specifically less than 10%, from the average value of the mechanical properties of the corresponding portion. The yield strength of a material represents the maximum stress it can withstand before it begins to permanently change shape, i.e., it indicates 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 region between the portions of the (multiple) soft regions (i.e., between the first soft portion and the second soft portion of the main soft region or between the main member and the (multiple) soft regions) may be less than 30 mm, specifically between 20 mm and 5 mm. The width of the transition region depends on manufacturing parameters such as the temperature difference between adjacent portions, or on the manufacturing process.

[0048] Further, in each example, the difference between the average yield strengths of two adjacent portions may be greater than 10%, specifically greater than 15%, and possibly greater than 20%.

[0049] In some examples, the main member may include regions made of hardened steel, specifically press-hardened steel. The main member may include regions made of ultra-high-strength steel (UHSS) with an ultimate tensile strength of 1,000 MPa, specifically 1,500 MPa or more.

[0050] Moreover, the energy absorption along the length of the main member can be customized in different ways. For example, when the cross-sectional area of the main member increases, more energy can be absorbed. Thus, the energy absorption can increase from a first cross-section of the main member closer to the first end to a more distant cross-section.

[0051] In some examples, the main member may include one or more ribs. The ribs may extend across the bottom wall or across one of the first side wall and the second side wall.

[0052] Throughout this disclosure, a rib can be understood as an elongated, generally straight portion of the main member for local reinforcement. The ribs can be manufactured during the stamping process. In some examples, the ribs can be formed using patchwork blanks, i.e., before the stamping process, the patchwork blanks are welded (e.g., spot welded) to the main blank. In other examples, the ribs can be formed as a deformation of the same main blank.

[0053] The presence of one or more ribs in the main member can contribute to adjusting the deformation behavior of the structural component. Compared with the main member, the ribs have lower ductility and higher resistance, which can help create specific bending positions in the structural component. Thus, the deformation of the structural component can be optimized. Especially when the structural component is configured to support bending loads, the energy absorption rate can be increased.

[0054] The number, position, and extensibility of the portions with mechanical properties different from the rest of the main member, as well as the number, position, and extensibility of the ribs in the structural component, can be selected according to the desired behavior of the structural component in terms of deformation (e.g., especially under bending loads caused by (simulated) impact or collision of the main member).

[0055] In various examples, the structural component may include additional members attached to the main member. The additional members can be, for example, plates or covers attached at the flanges of the main member. The additional members can also have similar dimensions and shapes as the main member, i.e., the structural component is formed by two similar parts.

[0056] In some examples, the additional members can be made of the same material as the main member and can be made by the same manufacturing process as the main member. In other examples, the additional members can be made with different processes and / or different steels. In some examples, the additional members can be cold formed using appropriate cold-formed steel.

[0057] In some examples, the (multiple) soft zones including the aforementioned first and second (and optional other) soft parts can also be formed in the attachment.

[0058] In another aspect, a method for manufacturing a structural member at least partially configured to support a bending load is provided to obtain a structural member for a vehicle frame as described in the present disclosure.

[0059] The method includes providing a main blank. The method further includes heating the main blank at least partially above the austenitizing temperature, wherein different parts of the main blank are heated differently compared to other parts of the main blank; and press-hardening the heated main blank to form the main member of the structural member. The formed main member defines a generally U-shaped cross-section along at least a portion of the main member, the U-shaped cross-section including a bottom wall, a first side wall and an outwardly extending first flange, and a second side wall and an outwardly extending second flange. Further, the main member includes a main soft zone having lower mechanical properties than other zones of the main member. Further, the main soft zone extends from a first longitudinal position to a second longitudinal position and includes a first soft part having generally constant mechanical properties and a second soft part having generally constant mechanical properties. At a longitudinal position between the first longitudinal position and the second longitudinal position (i.e., within the main soft zone), the first soft part is arranged adjacent to the second soft part. The mechanical properties of the first soft part are different from those of the second soft part.

[0060] The method can improve the deformation behavior of the structural member configured to support a bending load and can adjust how the structural member deforms during, for example, a vehicle collision. Thereby, the energy absorption of the structural member can be enhanced.

[0061] The main blank is to be understood herein as a blank for forming the main member, such as a metal sheet or a flat metal plate. The main blank can be made of hardenable steel, specifically boron steel. The thickness of the main blank can typically be between 1 and 2.5 mm.

[0062] In some examples of the method, the heating step includes heating the main blank generally uniformly above the austenitizing temperature and then cooling the parts of the main blank, particularly below the austenitizing temperature. The cooled parts can be adjacent to each other, i.e., the edge of one part contacts the edge of the adjacent part.

[0063] In some examples of the method, the cooling can include blowing air through nozzles against the parts of the main blank to be cooled.

[0064] The manner of cooling a specific portion of the main blank can produce precisely defined temperature regions and temperature gradients along and / or across the main blank. Thereby, the cooling effect can be localized, and the mechanical properties of different portions can be precisely controlled. This allows for predictable and substantially constant mechanical properties within each portion and relatively small transition regions between them.

[0065] In some other examples, the cooling can include reducing the temperature of the cooling portion by 100 degrees relative to other parts of the main member, and more specifically by 200 degrees relative to other parts of the main member.

[0066] In some examples, the cooling can be performed using a nozzle array or a nozzle matrix. Thereby, the nozzles can precisely define the portion of the main member to be cooled.

[0067] In various examples, the nozzles can propel compressed air with an overpressure of at least 2 bar, specifically 3 bar, and more specifically 4 bar. The overpressure should be understood as the pressure difference between the atmospheric pressure under normal conditions and the total pressure of the compressed air (i.e., the static pressure plus the 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 that is substantially parallel to the machining plane (i.e., the surface of the part). Thereby, the tangential nozzle can create a flow seal, which can prevent air from other nozzles from reaching a portion of the main blank. Thus, the tangential nozzle can be used to control the temperature gradient along and / or across the main blank.

[0069] In various examples, the nozzles can include nozzles configured to create a negative pressure region at a desired location inside the heating facility. The negative pressure region can be suitable for separating regions of different air temperatures. Description of the Drawings

[0070] Non-limiting examples of the present disclosure will be described below with reference to the drawings, in which:

[0071] Figure 1 An example of a structural component for a vehicle that is at least partially configured to support bending loads is schematically represented.

[0072] Figure 2 The yield strength of an example of a structural component after quenching is schematically shown as a function of the lateral position.

[0073] Figure 3 Two cross-sections of another example of a structural component are schematically shown.

[0074] Figure 4 Another example of a structural component for a vehicle that is at least partially configured to support bending loads is schematically represented.

[0075] Figure 5 Schematically shows yet another example of a structural component for a vehicle that is at least partially configured to support bending loads.

[0076] Figure 6 Schematically represents another example of a structural component for a vehicle that is at least partially configured to support bending loads.

[0077] Figure 7 Schematically shows yet another example of a structural component for a vehicle that is at least partially configured to support bending loads.

[0078] Figure 8a Schematically represents a perspective view of another example of a structural component for a vehicle that is at least partially configured to support bending loads.

[0079] Figure 8b Schematically represents Figure 8a a top view of the structural component shown in

[0080] Figure 8c Schematically represents Figures 8a to 8b a cross-section of the structural component shown in

[0081] Figure 9 is a flow chart of a method for manufacturing a structural component that is at least partially configured to support bending loads.

[0082] The accompanying drawings refer to example embodiments and are only used to assist in understanding the claimed subject matter and do not limit it in any sense. Detailed Description

[0083] Figure 1 Schematically shows a structural component 100 for a vehicle that is configured or at least partially configured to support bending loads. The structural component 100 includes a main member 110 that defines a generally U-shaped cross-section along at least a portion of the main member, the U-shaped cross-section including a bottom wall, a first side wall, and a second side wall.

[0084] The main member 110 extends from a first end 111 to a second end 112 along a longitudinal direction of the main member 110. The first end may be a bottom portion of the main member, the second end may be a top portion, and vice versa. The first end may be a front end (in the longitudinal direction of the vehicle), the second end may be a rear end (in the longitudinal direction of the vehicle), and vice versa. If the component is mounted generally along the lateral direction of the vehicle, the first end may be, for example, a left end and the second end may be a right end, and vice versa.

[0085] The main member 110 includes a main soft zone 170 that has lower mechanical properties than other zones of the main member 110. The main soft zone 170 extends from a first longitudinal position (closer to the first end) to a second longitudinal position (closer to the second end).

[0086] Further, the main soft zone 170 includes a first soft portion 120 having substantially constant (first) mechanical properties and a second soft portion 140 having substantially constant (second) mechanical properties. At a longitudinal position between the first longitudinal position and the second longitudinal position, i.e., at a longitudinal position within the main soft zone, the first soft portion 120 is disposed adjacent to the second soft portion 140. In various examples, the first soft portion 120 may be subjected to a first heat treatment, while the second soft portion 140 may be subjected to a second heat treatment. Further, the difference between the first heat treatment and the second heat treatment may result in the first soft portion 120 having a material microstructure different from that of the second soft portion 140.

[0087] Further, the second mechanical properties (of the second soft portion) may be lower than the first mechanical properties (of the first soft portion). Such a configuration may be beneficial for limiting the degree of intrusion in the event of an impact.

[0088] For example, in the case of a B-pillar, the main soft zone may be disposed in the lower half of the B-pillar, and specifically may be disposed at the bottom 40% of the B-pillar. The main soft zone in the B-pillar is typically provided to be able to absorb energy in the event of a side impact. The position of the soft zone will determine how the B-pillar will deform, and the main soft zone may particularly form a hinge-like portion, and the main soft zone is an area of the B-pillar that generally protrudes more inwardly than other parts of the B-pillar in the event of an impact. Providing the first soft portion with higher mechanical properties (i.e., higher yield strength and / or ultimate tensile strength) than the second soft portion may allow for energy absorption while limiting inward intrusion in the event of an impact, thereby enhancing occupant safety.

[0089] As Figure 1 shown, the main soft zone 170 of the main member 110 may further include an intermediate soft portion 130 having substantially constant (third) mechanical properties.

[0090] In the illustrated example, the first soft portion 120 may be disposed at a part of the first side flange and the second side flange, while the intermediate soft portion 130 may be disposed at a part of the first side wall 114 and the second side wall 115, i.e., arranged perpendicular to the center line C. Further, the third mechanical properties may be lower than the second mechanical properties.

[0091] Thus, the main member 110 may include a main soft zone 170, and the main soft zone 170 includes two or more parts that are different in mechanical properties, with one part adjacent to another part. The parts 120, 140, 130 may be arranged based on mechanical properties, that is, the part with the lowest mechanical property is arranged at the bottom wall, and the part with the highest mechanical property is arranged farthest from the bottom wall 113, and particularly the part with the highest mechanical property is arranged in one or both side flanges.

[0092] Throughout the present disclosure, the parts of the soft zone have been shown at one side of the structural member 100. However, it should be understood that any type of soft zone shown may or may not be symmetric with respect to the center line C of the structural member 100.

[0093] Figure 1 In the example of, the ultimate tensile strength of the main member 110 of the structural member 100 outside the main soft zone 170 may be mainly 1.000 Mpa or more, specifically 1.200 MPa or more, and more specifically 1.500 Mpa or more.

[0094] In each example, the yield strength of the second soft part 140 may be between 300 and 600 MPa, specifically between 400 and 500 MPa (for example, the average value is about 450 MPa). In each example, the yield strength of the first soft part is between 600 and 950 MPa, specifically between 650 and 800 MPa (for example, the average value is about 725 MPa). The yield strength of the main member outside the main soft zone may (mainly) be higher than 1.000 MPa.

[0095] Furthermore, the structural member 100 has a bottom wall 113, which may be substantially perpendicular to the first side wall 114 and the second side wall 115 (clearly visible in Figure 3 ). In other examples, the bottom wall 113 may define an angle different from 90 degrees with respect to the first side wall 114 and the second side wall 115.

[0096] Furthermore, the radius of curvature between the bottom wall 113 and the first side wall 114 and the second side wall 115 may be adjusted according to the specifications of the structural member 100 (that is, the mechanical properties of the materials used, the desired maximum local strength, etc.).

[0097] Such as for example Figure 3As shown, the structural member 110 may include a first side flange 116 and a second side flange 117 extending outwardly from a first side wall 114 and a second side wall 115, respectively. The flanges 116, 117 provide convenient attachment points, such as for riveting or spot welding to connect the structural member 100 to other parts of the vehicle (e.g., other components of the vehicle's structural frame). As previously discussed, the radius of curvature between the first side wall 114 and the second side wall 115 and the flanges 116, 117 may also vary according to the specifications of the structural member 110.

[0098] In various examples, a portion of the main soft zone 170 (i.e., the first soft portion 120 or the intermediate soft portion 130) may be generally located at the first flange 116 and the second flange 117.

[0099] The main member 110 may have a transition zone 150, i.e., between different portions of the main soft zone 170 or between the main soft zone of the main member 110 and a stiffer zone, having a width of less than 30 mm, specifically between 20 mm and 5 mm.

[0100] In some examples, the main member 110 may be made of boron steel, such as For example 1500 (22MnB5 steel with or without a protective coating), 2000 (37MnB5) or any martensitic steel or ultra-high-strength steel (UHSS). Available from ArcelorMittal.

[0101] 1500 is supplied in a ferrite-pearlite phase. It is a fine-grained structure distributed in a uniform pattern. Its mechanical properties are related to this structure. After heating, hot stamping process and subsequent quenching, a martensitic microstructure is produced. Therefore, the tensile strength and yield strength are significantly increased.

[0102] The composition of 1500 is summarized as follows by weight percentage (the rest being iron (Fe) and impurities):

[0103] Carbon (C) maximum percentage (%): 0.25

[0104] Silicon (Si) maximum percentage (%): 0.4

[0105] Manganese (Mn) maximum percentage (%): 1.4

[0106] Phosphorus (P) maximum percentage (%): 0.03

[0107] Sulfur (S) maximum percentage (%): 0.01

[0108] Aluminum (Al) (%): 0.01 - 0.1

[0109] Maximum proportion of titanium (Ti) (%): 0.05

[0110] Maximum proportion of niobium (Nb) (%): 0.01

[0111] Maximum proportion of copper (Cu) (%): 0.20

[0112] Maximum proportion of boron (B) (%): 0.005

[0113] Maximum proportion of chromium (Cr) (%): 0.35

[0114] 2000 is another boron steel 37MnB5 with higher strength. After the quenching process of the hot stamping die, The yield strength of 2000 can be 1300 MPa or above, and its ultimate tensile strength can be above 1800 MPa.

[0115] The composition of 2000 is summarized as follows by weight percentage (the rest is iron (Fe) and impurities):

[0116] Maximum proportion of carbon (C) (%): 0.36

[0117] Maximum proportion of silicon (Si) (%): 0.8

[0118] Maximum proportion of manganese (Mn) (%): 0.8

[0119] Maximum proportion of phosphorus (P) (%): 0.03

[0120] Maximum proportion of sulfur (S) (%): 0.01

[0121] Aluminum (Al) (%): 0.01 - 0.06

[0122] Maximum proportion of titanium (Ti) (%): 0.07

[0123] Maximum proportion of niobium (Nb) (%): 0.07

[0124] Maximum proportion of copper (Cu) (%): 0.20

[0125] Maximum proportion of boron (B) (%): 0.005

[0126] Maximum proportion of chromium (Cr) (%): 0.50

[0127] Maximum proportion of molybdenum (Mb) (%): 0.50

[0128] 22MnB5 and other boron steels can be provided with an aluminum-silicon coating to avoid decarburization and scaling during the forming process.

[0129] Several 22MnB5 steels with similar chemical compositions are commercially available. However, the exact amounts of each component in the 22MnB5 steel may vary slightly depending on the manufacturer. Other ultra-high strength steels include BTR165 available from Benteler.

[0130] Figure 2 is a simplified diagram showing the average yield strength of the soft zone 170 of the structural member 100 in the transverse direction perpendicular to the longitudinal direction ( Figure 1 the center line in the longitudinal direction has been shown). The horizontal axis represents the transverse position of the structural member 100 from Figure 1 the center line C in to one end of the flange 116. The vertical axis represents the average yield strength for a given cross-section after quenching the structural member (i.e., once at room temperature after press hardening).

[0131] Note that Figure 2 the reference numerals in Figure 1 are associated with the features in Figure 1 . Thus, the area in the diagram with a given reference numeral is not the feature itself, but points to the yield strength of the corresponding feature in

[0132] In the materials used for hot stamping the structural members of the present disclosure, the yield strength (or tensile strength) is inversely proportional to the ductility, that is, as the microstructure of the material changes, when the ductility decreases, the yield strength and the ultimate tensile strength increase, and vice versa.

[0133] Thus, Figure 2 shows that the yield strength at the bottom wall 113 (i.e., at the second soft part 140) is relatively low and almost constant. Then, the yield strength of the main member 110 increases (and the ductility thus decreases) at the first transition zone 150 to the higher level of yield strength of the intermediate soft part 130. This change in mechanical properties occurs over a relatively short width, for example, with a width on the order of up to 20 mm. After this first transition zone 150, the main soft zone 170 includes a first soft part 120 that is stronger and less ductile compared to the second soft part 140 and the intermediate part 130.

[0134] The local yield strength of the soft zone is higher at the second transition zone 150 after the intermediate soft part 130. The third plateau after the second transition zone 150 corresponds to the first soft part 120, where the mechanical properties within the soft zone 170 are higher. As can be seen from Figure 2 the yield strength gradients in different transition zones 150 can be different.

[0135] Note that Figure 2The specific values of strength or position are not included as they are only used as examples of the present disclosure. Also, compared to the lengths of the various parts of the main soft zone 170, the widths of some of the transition zones 150 may appear relatively large, but this is done to clearly illustrate potential differences in the yield strength gradient. The microstructure that can be obtained can be controlled by appropriate heat treatment.

[0136] The difference between the average yield strengths of two adjacent parts 120 - 130, 130 - 140 can be greater than 10%, specifically greater than 15%, and even greater than 20%. In each example, the difference between the average yield strengths of two adjacent parts may not be the same as the difference between two other adjacent parts. For example, the difference between the average yield strengths of parts 120, 130 can be 10%, while the difference between the average yield strengths of parts 130, 140 can be 15%.

[0137] Figure 3 Two cross - sections schematically showing examples of a structural component are presented. These cross - sections and other cross - sections can belong to the same structural component, i.e., the structural component can have cross - sections that vary along the longitudinal direction, or they can be cross - sections from different structural components.

[0138] Although not shown in the Figure 3 example, the bottom wall 113 can be curved or include depressions or protrusions along the bottom. This also applies to the side walls 114, 115, which do not necessarily have to be completely straight. The side walls 114, 115 can include straight portions with curved transition zones therebetween. Additionally, the side walls 114, 115 can be symmetric or not symmetric. For example, the height of the first side wall 114 can be different from the height of the second side wall 115. In some examples, the height along the longitudinal direction of the first side wall 114 and / or the second side wall 115 can also vary. In each example, the width of the bottom wall 113 can be different from the height of the first side wall 114 and / or the second side wall 115. Other examples can include any combination of the above examples.

[0139] The shapes and sizes of the flanges 116, 117 can be set to be located above a specific vehicle component and can be used to join the structural component to other components, such as other vehicle frame components.

[0140] As Figure 3 shown, the transition zones 150 between the first soft part and another soft part (the intermediate soft part or the second soft part) can be located at different points along the transverse direction of the main member 110. For example, the transition zone 150 in the first cross - section (left figure) is relatively close to the flanges 116, 117, while the transition zone 150 in the second cross - section (right figure) is relatively close to the bottom wall 113. In Figure 3In the left - hand example, the transition zone 150 can be located below 20% of the height of the side wall. The position of the transition zone 150 can be established such that a specific kinematics of the structural component is achieved after a bending impact.

[0141] Figure 4 Another example of a structural component 100 for a vehicle is schematically shown, where the structural component is configured or at least partially configured to support bending loads. In this example, the main member 110 includes a main soft zone 170, which has a lower yield strength and / or ultimate tensile strength than the rest of the main member 110. The main soft zone in this example includes a first soft part 120 and a second soft part 140 separated by a transition zone 150 near the first flange 116 and the second flange 117. The two parts 120, 140 can be more ductile than the rest of the stiffer part of the main member. In particular, the two parts can have a higher elongation at break and / or an increased rate of reduction of area before fracture, i.e., they can be more ductile than the rest of the main member 110.

[0142] Furthermore, the two parts 120, 140 have different mechanical properties. According to the present disclosure, other numbers of parts (i.e., four or more parts) and other relative dimensions can be included in the structural component 100.

[0143] In the example shown, the local yield strength of each part 120, 140 can vary by less than 15% from the average yield strength of the corresponding part. That is, the yield strength and / or ultimate tensile strength can be substantially constant within each part 120, 140.

[0144] As Figure 4 shown, the main member 110 can include a transition zone 150 between the soft zone 170 and other zones of the main member, the width of which is less than 30 mm, specifically between 20 mm and 5 mm. The width of the transition zone 150 can depend on manufacturing parameters such as the temperature difference between adjacent parts, or on the procedure followed for manufacturing the structural component.

[0145] The structural component 100 includes an additional member 180 attached to the main member 110. The additional member 180 can be a cover or a plate. The additional member 180 can be attached at the first side flange 116 and the second side flange 117. At the same longitudinal position where the main soft zone 170 is formed in the main member 110, the additional member 180 can also include a soft zone. In other examples, no soft zone is provided in the additional member. In some examples, the steel (e.g., cold - formed steel) of the additional member 180 can be different from the steel of the member 110.

[0146] In other examples not shown, the additional member can also have a U - shaped cross - section similar to the main member 110.

[0147] Figure 5 Another example of a structural component for a vehicle is schematically shown, where the structural component is at least partially configured to support a bending load. In this example, the structural component 100 is a B-pillar, but other vehicle components such as a door ring, a rear sill, and a door sill panel can also be used to illustrate the present disclosure. Large structural components of a vehicle (such as an integrated structure including, for example, a floor panel or a rear frame) can have a part designed to support a bending load and other parts designed to support other types of loads (i.e., compressive loads).

[0148] In Figure 5 , a bending impact can be received therein perpendicular to the longitudinal direction of the main member 110. The main member 110 is a B-pillar, particularly a "central" B-pillar, or a load-bearing member of the B-pillar. The complete B-pillar can include, for example, other inner covers and other outer covers.

[0149] Due to the introduction of a soft zone 170, where parts 120, 140 have lower mechanical properties, i.e., lower tensile strength and yield strength, than the rest of the main member 110, the deformation of the main member 110 can start and concentrate in this part rather than any other area.

[0150] The main soft zone 170 in the B-pillar 100 can be located below 50% of the height of the B-pillar, specifically below 33% of the height of the B-pillar. The width of the main soft zone can be at least 5 cm, specifically at least 10 cm. The lowermost part of the B-pillar 100 can be hard.

[0151] As Figure 5 shown, the structural component 100 can further include a secondary soft zone 171 spaced apart from the main soft zone 170 in the longitudinal direction. For example, the secondary soft zone 171 can have mechanical properties different from those of the main soft zone 170.

[0152] In various examples, the secondary soft zone 171 can have higher mechanical properties than the main soft zone 170 and can be located near the second end 112 to enhance the second deformation point. The secondary soft zone 171 can include more than two parts 121, 131, as previously discussed for the main soft zone 170. In various examples, the (multiple) transition zones 150 between two or more parts 121, 141 can be located at a lateral position different from that of the main soft zone 170.

[0153] Figure 6 Another example of a structural component 100 for a vehicle frame is schematically shown, where the structural component is at least partially configured to support a bending load. In this example, the structural component 100 is a single door ring of a vehicle. The door ring can be a front door ring, a rear door ring, or a double door ring.

[0154] The front door ring extends from the hinge pillar and the A-pillar to the B-pillar, where the sill panel part connects the B-pillar to the hinge pillar. The rear door ring extends from the B-pillar to the C-pillar, and the two are connected to each other by the sill panel part and the roof rail part.

[0155] In this example, the double door ring includes a B-pillar part, a sill panel part, a hinge part, an A-pillar part, and a C-pillar part. The double door ring can be formed by combining different blanks into a combined blank and then forming the combined blank into an integral double door ring.

[0156] The main member 110 in this example constitutes the door ring. The main member 110 includes a main soft zone 170 and a secondary soft zone 171, where the three parts 120, 130, 140 have a lower yield strength and / or ultimate tensile strength than the rest of the main member 110. The three parts 120, 130, 140 can be more ductile than the rest of the harder parts of the main member 110. In particular, these three parts 120, 130, 140 can have a higher elongation at break, and / or an increased rate of reduction of area before fracture.

[0157] In other examples, the structural member can be a front door ring or a rear door ring. The front door ring and the rear door ring can include a main member that includes a main soft zone. In a further example, the front door ring and / or the rear door ring can further include a secondary soft zone.

[0158] The main soft zone 170 can be partially located in the B-pillar part 100 and partially in the sill panel part of the main member. In the B-pillar part 100, the main soft zone 170 can be located below 50% of the height of the B-pillar part, specifically below 33% of the height of the B-pillar part. The B-pillar part 100 extends in a longitudinal (substantially vertical) direction and has a substantially U-shaped cross-section. The sill panel part of the main member also has a substantially U-shaped cross-section and extends in a substantially horizontal direction.

[0159] In particular, as can be seen in the example of Figure 6 , the main member 110 can include the main soft zone 170 located in the first side wall and the first flange of the U-shape of the main member 110 and the secondary soft zone 171 located in the second side wall and the second flange of the main member 110.

[0160] In Figure 6 's example, the three parts 120, 130, 140 of the main soft zone 170 and the secondary soft zone 171 are arranged substantially symmetrically with respect to the U-shape. The second soft part 140 in each of these soft zones is arranged at the first side flange and the second side flange, and the middle soft part 130 and the first soft part 120 are arranged at the first side wall and the second side wall.

[0161] In this example, the yield strength of the second soft portion 140 can be between 300 and 600 MPa, specifically between 300 and 500 MPa, the yield strength of the first soft portion 120 can be between 600 and 950 MPa, specifically between 650 and 800 MPa, and the yield strength of the intermediate portion 130 can be between 300 and 500 MPa, specifically between 400 and 500 MPa.

[0162] The door ring of the vehicle can receive a bending impact in the main member 110 perpendicular to the longitudinal direction of the main member. The door ring can effectively absorb the bending impact energy while controlling the deformation kinematics and preserving the interior space of the vehicle.

[0163] Figure 7 Another example of an integral double door ring of a vehicle is schematically shown, which is at least partially configured to support a bending load.

[0164] In Figure 7 the example, the main member 110 can include the sill panel portion of the double door ring. The main member 110 can include a main soft zone 170 located at the top portion of the sill panel portion (i.e., at the first side wall and the first flange of the main member 110). The main member 110 can further include a secondary soft zone 171 located at the top portion of the sill panel portion.

[0165] Similar to Figure 6 the main member of Figure 7 the example, the main soft zone 170 of the member of

[0166] Figure 8a and Figure 8b A perspective view and a top view of another example of a structural member 100 for a vehicle frame are schematically shown, wherein the structural member is at least partially configured to support a bending load. The structural member 100 can be a tubular reinforcement of the vehicle. In this example, the structural member 100 is a reinforcement of the vehicle's sill panel.

[0167] In some examples, the vehicle's sill panel can generally be formed by a main member having a substantially U-shaped cross-section and an additional member attached to the main member. When the main member and the additional member are attached together, a closed space can be formed, and the tubular reinforcement can be configured to be located in the closed space of the vehicle's sill panel. Many different sill panel configurations are possible, where a sill panel with a closed cross-section is provided and the reinforcement can be placed therein.

[0168] The reinforcement of the vehicle sill panel includes a main member 110 having a generally U-shaped cross-section. The reinforcement of the vehicle sill panel further includes 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 can be a cover or a plate.

[0169] In addition, Figure 8c is shown Figure 8a and Figure 8b a cross-section of the reinforcement of the vehicle sill panel as shown in

[0170] As Figure 8b and Figure 8c schematically shown, the reinforcement of the vehicle sill panel can include a main soft zone 170 and a secondary soft zone 171 located in the first side wall and the second side wall of the U-shaped cross-section of the reinforcement of the vehicle sill panel.

[0171] The main member 110 includes 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 110, that is, the main soft portions extend along the entire longitudinal length of the main member 110.

[0172] As Figure 8b and Figure 8c schematically shown, the first soft portion 120 and the second soft portion 125 have the same mechanical property. The mechanical property of the intermediate soft portion 130 is different from the mechanical properties of the first soft portion 120 and the second soft portion 140.

[0173] In this example, the yield strength of the first soft portion 120 and the second soft portion 125 can be between 600 and 950 MPa, specifically between 650 and 800 MPa, and the yield strength of the intermediate portion 130 can be between 300 and 500 MPa, specifically between 400 and 500 MPa.

[0174] Figures 8a to 8c The vehicle sill panel reinforcement of

[0175] In some examples, ribs may be included in the main member 110 to further enhance the strength difference between parts of the main member 110. In fact, the characteristics of the ribs, including their number, shape, size, location, and extension on the main member 110, may be customized to adjust the behavior of the structural member 100 when subjected to bending loads. The ribs create stiffer and less bendable regions in the structural member 100. In this way, the behavior of the main member 110 and the structural member 100 can be better controlled during an impact.

[0176] In another aspect of the present disclosure, a method 200 for manufacturing a structural member 100 is provided, which is at least partially configured to support bending loads as described throughout the present disclosure. Any structural member provided herein may be manufactured according to an example of this method.

[0177] The method includes providing a main blank in block 201. The method further includes heating the main blank at least partially above the austenitizing temperature in block 202, wherein the adjacent first soft portion 120 and second soft portion 140 are heated differently compared to other parts of the main blank.

[0178] And, the method includes press hardening the heated main blank in block 203 to form the main member of the structural member 100. The formed main member 110 defines a generally U-shaped cross-section, including a bottom wall 113, a first side wall 114, a first side flange extending outward from the first side wall 114, and a second side wall 115 having a second side flange extending outward.

[0179] Further, the main member 110 includes a main soft zone 170, which has lower mechanical properties than other zones of the main member 110. Additionally, the main soft zone 170 includes a bottom soft portion 120 having generally constant first mechanical properties and a side soft portion 140 having generally constant second mechanical properties.

[0180] Within the soft zone, at a given longitudinal position, the bottom soft portion 120 is at least disposed at the bottom wall 113, and the side soft portion 140 is at least partially disposed in the first side wall 114 and the second side wall 115 or the first side flange and the second side flange.

[0181] In various examples, as mentioned previously, the first mechanical properties of the bottom soft zone are lower than the second mechanical properties of the side soft portion. Within the different soft portions, the mechanical properties may be generally constant.

[0182] Further, the method 200 may be applicable to forming a main member 110 having any combination of the previously discussed technical features.

[0183] The main blank can be made of any type of hardenable steel, in particular boron steel, as previously discussed for the structural component 100.

[0184] The heating step 202 of the method 200 can include heating the main blank generally uniformly above the austenitizing temperature and subsequently cooling portions of the main blank, in particular below the austenitizing temperature.

[0185] In various examples, the main blank can be heated above Ac3 and portions of the main blank can be cooled to a temperature below Ac3, even below Ac1 before deforming the blank. Other portions can be maintained above Ac3 until the blank is deformed, or can be temporarily cooled and then reheated above Ac3 again.

[0186] For example, during a first stage of the heating step 202, the main blank can be generally uniformly heated above Ac3 in a main furnace. Then, in a second stage of step 202, portions of the main blank corresponding to (formed) soft zones can be cooled to a temperature below Ac3 while other portions are maintained at a higher temperature, e.g., above Ac3. Additionally, in a third stage of step 202, the main blank can be reheated such that portions corresponding to the soft zones are maintained below Ac3 and the remaining portions of the main blank are maintained at a temperature above Ac3. In the case where the overall temperature of the main blank has decreased during the second stage, the third stage of step 202 can be used to raise the temperature of the remaining portions of the main blank above Ac3. The three stages of step 202 can be accomplished in the same furnace or in a separate facility downstream of the main furnace.

[0187] In some examples, the heating step 202 of the method 200 can include blowing air through nozzles against portions of the main blank to be cooled. The nozzles can be distributed in an array or 2D matrix form to provide a more precise temperature profile along and / or across the main blank. This can be accomplished in the same furnace in which the main blank is heated or in a separate facility downstream of the main furnace.

[0188] The inventors have found that this method of partially cooling a heated blank by means of pressurized nozzles allows cooling of specific portions of the blank with very little impact on the temperature of the remaining portion of the blank. This method allows precise control of the temperature profile along the heated main member of the structural component and the resulting material microstructure. Further, the method represents a cost-effective way to form the structural components of the present disclosure.

[0189] The cooling nozzle can set a temperature difference of at least 100 degrees, specifically at least 200 degrees, between at least the bottom soft part 120 of the main member and the rest of the main member 110. Further, several temperature differences can be set between the various parts of the main member. For example, three or more parts 120, 140, 130 can be set in the main member 110, and the temperature of each part is different.

[0190] In one example, the parts of the blank to be fully hardened (most or all areas outside the main soft zone) can be maintained at a temperature of 900 °C or higher. The bottom soft part can be reduced to a temperature below Ac1, for example, between 600 and 700 °C. The side soft part 120 can have a temperature higher than the bottom soft part but lower than the parts of the blank to be fully hardened. The temperature of the side soft part can be, for example, between 700 and 800 °C. While reducing the temperature of the various parts of the blank, other parts can be maintained above the austenitizing temperature, for example, above 900 °C.

[0191] In some examples, the cooling can drop to a lower range than that mentioned above and then be reheated at least to some extent. When the blank is positioned in the press tool, different parts of the blank can have different temperatures, while the temperature within these positions is substantially constant.

[0192] Thus, different temperatures may result in different microstructures or strength properties being set in the corresponding parts of the main member 110, particularly during subsequent rapid cooling (“quenching”), for example, in the die of a stamping tool.

[0193] In various examples, the main member is formed during the press hardening step 203 to form a shaped part while being quenched to below 400 °C, or specifically below 300 °C.

[0194] In various examples, the cooling nozzle can include at least one tangential nozzle. The tangential nozzle can push compressed air having a directional component substantially parallel to the machining plane (i.e., the surface of the part). The tangential nozzle pushes the compressed air against the surface of the part at an angle other than zero. For example, the tangential nozzle can be oriented such that the air flow from the tangential nozzle and a vector orthogonal to the surface of the part define an angle of less than 30 degrees, more specifically less than 15 degrees.

[0195] Thus, the tangential nozzle can create a flow seal, which can prevent air from other nozzles from reaching a given part of the main blank. Therefore, the tangential nozzle can be used to control the temperature gradient along and / or across the main blank.

[0196] In some examples, the cooling nozzle can be mounted on a moving frame that is capable of displacing and rotating the individual nozzles relative to the main blank.

[0197] Although only some examples are disclosed herein, other alternatives, modifications, uses, and / or equivalents of these examples are possible. Also, all possible combinations of the described examples are covered. Thus, the scope of the present disclosure should not be limited by the specific examples, but should be determined only by a reasonable reading of the following claims.

Claims

1. A structural component (100) for a vehicle frame, the structural component being at least partially configured to support bending loads, and comprising: A main member (110) that extends from a first longitudinal position to a second longitudinal position and defines a generally U-shaped cross-section along at least a portion of the main member, the U-shaped cross-section including a bottom wall (113), a first side wall (114) having an outwardly extending first side flange, a second side wall (116), and an outwardly extending second side flange, The main member (110) extends from a first end (111) to a second end (112) in the longitudinal direction of the main member (110); The main member (110) includes a main soft zone (170) having lower mechanical properties than other zones of the main member (110), where The main soft zone (170) includes a first soft portion (120) having generally constant mechanical properties and a second soft portion (140) having generally constant second mechanical properties; and At a longitudinal position between the first longitudinal position and the second longitudinal position, the first soft portion (120) is disposed adjacent to the second soft portion (140), and wherein the mechanical properties of the first soft portion (120) are different from the mechanical properties of the second soft portion (140), wherein the mechanical properties are ultimate tensile strength and yield strength.

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

4. The structural component (100) according to any one of claims 1 to 3, wherein, The main soft zone (170) is formed by subjecting the main soft zone (170) to a heat treatment different from that of other zones of the main member (110).

5. The structural component according to any one of claims 1 to 4, wherein, The second soft portion (140) is a bottom soft portion disposed at least partially at the bottom wall (113), and the first soft portion (120) is a side soft portion disposed at least partially in the first side flange and the second side flange and / or in the first side wall and the second side wall.

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

7. The structural component (100) according to claim 5 or 6, wherein, The side soft part is arranged at the first side flange and the second side flange, and is at least partially arranged in the first side wall (114) and / or the second side wall (115).

8. The structural component according to any one of claims 1 to 4, wherein, the second soft part (140) is arranged in the first side flange, and the first soft part (120) is arranged in the first side wall.

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

10. The structural component (100) according to any one of claims 1 to 9, wherein, at the longitudinal position, the main soft zone (170) includes an intermediate soft part (130) having substantially constant mechanical properties, and the intermediate soft part substantially connects the first soft part (120) to the second soft part (140).

11. The structural component (100) according to any one of claims 1 to 10, wherein, the main member (110) outside the main soft zone mainly has an ultimate tensile strength of 1.200 MPa or more, and more specifically 1.500 MPa or more.

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

13. The structural component (100) according to any one of claims 1 to 12, wherein, the difference between the average yield strengths of the first soft part (120) and the second soft part (140) is greater than 10%, and specifically greater than 20%.

14. The structural component (100) according to any one of claims 1 to 13, further comprising an additional member (180) attached to the main member (110).

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

16. The structural component (100) according to any one of claims 1 to 15, wherein, the structural component (100) is any one of a B-pillar, a door ring, a rear longitudinal beam, a vehicle sill panel, and an integrated structure including a floor panel or a rear frame, or is formed as a part of any one of a B-pillar, a door ring, a rear longitudinal beam, a vehicle sill panel, and an integrated structure including a floor panel or a rear frame.

17. A method (200) for manufacturing a structural component (100) for a vehicle frame, the method (200) comprises: providing (201) a main blank; heating at least a part of the main blank to a temperature above the austenitizing temperature, wherein different parts (120, 140) of the main blank are heated differently compared to other parts of the main blank; and Press harden (203) the heated main blank to form the main component (110) of the structural component (100), the main component (110) defining a generally U-shaped cross-section along at least a portion of the main component, the U-shaped cross-section including a bottom wall (113), a first side wall (114) and an outwardly extending first side flange, a second side wall (115) and an outwardly extending second side flange, and the main component including a main soft zone (170) having lower mechanical properties than other zones of the main component (110), wherein the main soft zone (170) extends from a first longitudinal position to a second longitudinal position and includes a first soft portion (120) having generally constant mechanical properties and a second soft portion (140) having generally constant mechanical properties; and at a longitudinal position between the first longitudinal position and the second longitudinal position, the first soft portion (120) is arranged adjacent to the second soft portion (140), wherein the mechanical properties of the first soft portion (120) are different from the mechanical properties of the second soft portion (140).

18. The method (200) according to claim 17, wherein, heating (202) the main blank includes heating the main blank generally uniformly above the austenitizing temperature and then cooling portions of the main blank, in particular below the austenitizing temperature.

19. The method (200) according to claim 18, wherein, cooling the portions of the main body includes blowing pressurized air against each of the portions through a nozzle.

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

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