Method and heating system for heating a blank

Abstract

This disclosure relates to a method for manufacturing a part from a blank. The method includes placing the blank on a conveyor system and transporting the blank toward a furnace. The method further includes preheating one or more pre-selected areas of the blank while transporting the blank toward the furnace, wherein the pre-selected areas of the blank are preheated by laser heating using one or more laser heating heads. Finally, the method includes transporting the blank through the furnace. This disclosure further relates to a preheating system for heating blanks in a production line.

Description

Technical Field

[0001] This application claims the benefit of EP23382780.7, filed on Jul. 26, 2023.

[0002] The present disclosure relates to a heating system for heating a blank, particularly a heating system equipped with a preheating system. The present disclosure further relates to a method for manufacturing a component, including hot forming of the blank.

Background Art

[0003] In the automotive industry, in order to meet the manufacturing standards of lightweight vehicles, the development and introduction of lightweight materials or components are becoming increasingly important. The demand for lightweighting is particularly driven by the goal of reducing CO2 emissions. In addition, the growing concern regarding passenger safety has also led to the adoption of materials that improve the integrity and energy absorption of vehicles during collisions.

[0004] In press hardening, also known as hot formed die quenching (HFDQ), typically, boron steel sheets are used to produce stamped parts having ultra-high strength steel (UHSS) properties with a tensile strength of, for example, 1500 MPa or above 2000 MPa. The increase in strength enables the use of thinner gauge materials, resulting in weight reduction compared to conventional cold press soft steel parts. Throughout the present disclosure, UHSS can be regarded as steel having an ultimate tensile strength of 1000 MPa or above, particularly after the press hardening process.

[0005] In the HFDQ process, the blank to be hot formed can be heated to a predetermined temperature above, for example, the austenitization temperature (particularly between Ac3 and, for example, the evaporation temperature of the blank's coating). For this purpose, a furnace system can be used. By heating the blank, the strength of the blank is reduced and the formability is improved, facilitating the hot stamping process.

[0006] Several ultra-high-strength steels (UHSS) are known for hot stamping and hardening. The blanks to be hot-formed can be made from boron steel, with or without coating, such as Usibor® (22MnB5), commercially available from ArcelorMittal.

[0007] Typical vehicle parts that can be manufactured using the HFDQ process include door beams, bumper beams, cross / side members, A / B pillar reinforcements, front and rear rails, seat cross members, and roof rails.

[0008] It is known that introducing soft regions within a component can improve its ductility and energy absorption in specific areas. This locally improves ductility while maintaining the high overall strength required. By locally adjusting the microstructure and mechanical properties of a given structural component to include regions of very high strength (very hard regions), i.e., regions of high ultimate tensile strength and high yield strength, and regions of high ductility (softer regions), i.e., regions of low ultimate tensile strength and low yield strength with large elongation at fracture, it may be possible to improve its overall energy absorption during impact, maintain its structural integrity, and reduce its total weight. Such soft regions may also favorably alter the kinematic behavior of the component if it breaks during impact.

[0009] Known methods for forming highly ductile regions ("soft zones") in vehicle structural components include providing a tool comprising a pair of complementary upper and lower mold units, each unit having a separate mold member (steel block).

[0010] Mold components can be designed to operate at different temperatures so that different regions of the part being formed during the quenching process have different cooling rates, thereby obtaining different material properties in the final product, such as a softer region that generally has lower intrinsic tensile strength and lower yield strength but higher elongation at break. For example, by cooling one mold component, the corresponding region of the part being manufactured can be quenched at a high cooling rate, thereby rapidly lowering the temperature of the part and obtaining a hard martensite microstructure. By heating another adjacent mold component, the corresponding portion of the part being manufactured can be cooled at a lower cooling rate, resulting in a softer microstructure, such as one containing bainite, ferrite, and / or pearlite. Such regions of the part may be maintained at a higher temperature than the rest of the part when it is ejected from the mold.

[0011] Other methods for obtaining hot-stamped parts with different mechanical properties include, for example, altering the local microstructure through pre-stamping or differential heating, and localized heat treatment after the stamping process to obtain different mechanical properties. Further possibilities include the use of patchwork blanks and tailor-welded blanks (TWBs) that combine different thicknesses and / or materials in the blank.

[0012] UHSS can exhibit tensile strengths of 1500 MPa, or even over 2000 MPa, especially after press hardening. Once hardened, UHSS can possess a martensite microstructure. This microstructure allows for increased maximum tensile strength and yield strength per unit weight.

[0013] In addition to the aforementioned ultra-high-strength steels, more ductile steels can also be used in structural frameworks requiring energy absorption. These steels can be used in hot stamping processes, but a martensitic microstructure is not obtained during the process. Ductibor® 1000 is an example of a suitable more ductile steel.

[0014] Blanks of different thicknesses may not be heated uniformly in the furnace; that is, the interior of thicker areas may not be heated sufficiently, resulting in uneven temperature distribution throughout the blank. In some cases, blanks may be made of different materials, i.e., have different properties. Such blanks may be formed, for example, by joining at least two blanks made of different materials (which may also be of different thicknesses). Thus, the resulting blank will have the properties of the joined materials. An example of blanks of different thicknesses is shown in document WO2020 / 002335A1, which discloses a method for manufacturing a one-piece body side structure frame for vehicles. The one-piece body side structure frame is obtained by deforming a composite blank, formed by joining multiple blanks, to form one or more overlapping regions formed by partially overlapping the blanks.

[0015] If the entire blank is not uniformly heated in the furnace to a predetermined temperature, such as the austenitization temperature, the results of the subsequent hot deformation process may be unsatisfactory. Specifically, parts of the blank may not be sufficiently malleable and may not deform properly, potentially leading to blank breakage during the deformation process. Furthermore, due to an insufficient temperature gradient, the ferrite-pearlite initial phase may not completely transform into austenite throughout the entire thickness of the blank. As a result, the desired microstructure, such as martensite, may not form in the underheated zones during the subsequent quenching process. Moreover, overheating of the blank can cause undesirable changes in material properties and / or affect the coating.

[0016] Blanks containing thick areas may be left in the furnace for extended periods to ensure that such thick areas are sufficiently heated. The time the blanks remain in the furnace can be altered, for example, by reducing the speed of the conveyor system or by increasing the length of the furnace. Depending on the process, some furnaces or furnace systems may be 25 meters or longer, and furthermore, as the furnace length increases, the occupied space increases accordingly. However, such alternatives may significantly increase the overall processing time.

[0017] Document WO2018 / 115298A1 discloses a method for manufacturing steel parts from a blank, which includes holding the blank in a predetermined preheating position in front of the furnace. However, the system disclosed in WO2018 / 115298A1 has proven unsuitable for preheating very large blanks, such as integrated door rings. Furthermore, holding the blank slows down the manufacturing process.

[0018] A blank processing method and tools are needed that at least partially solve some of the aforementioned problems. [Overview of the project]

[0019] In a first embodiment, a method for manufacturing a part from a blank is provided. This method includes placing the blank on a conveyor system and transporting the blank toward a furnace. Furthermore, this method includes preheating one or more pre-selected areas of the blank while transporting it toward the furnace. This method also includes transporting the blank through the furnace. In this method, the preheating includes laser heating of pre-selected areas of the blank using one or more laser heating heads.

[0020] By heating a pre-selected area of ​​a blank using one or more laser heating heads, the pre-selected area can be preheated quickly and efficiently. Laser heating provides precise heating of the pre-selected area, enabling preheating of specific areas of blanks of various sizes and shapes. No extra time is required to preheat the pre-selected area, and high throughput can be maintained throughout the heating operation. Since one or more pre-selected areas are preheated while the blank is being transported to the furnace, the pre-selected area can be heated in a continuous, nonstop operation. In addition, since preheating is performed on the same conveyor that leads the blank to the furnace, the temperature of the preheated area does not decrease when it is transferred from the preheating system to the furnace.

[0021] In some cases, the laser heating head can be a multi-axis laser heating head. This allows for adjustment of the direction of the laser beam, enabling precise preheating of pre-selected areas of blanks of different sizes and shapes.

[0022] In some examples, preheating may further involve moving one or more laser heads perpendicular to the blank's transport direction. As the blank moves along the transport direction, the laser moves laterally relative to this direction, reaching different areas of the blank as needed. Different blanks may have different heating requirements. The laser heating heads may be adjustable to suit the dimensions and characteristics of each blank. The intensity of the heating process is variable, and the laser heating can be adjusted to suit the needs of different blanks and / or different areas of the blanks. The speed of the laser heating heads, the size of the laser spots, and the orientation of the laser heating heads can be varied during operation, particularly depending on the selected area being preheated.

[0023] In some examples, preheating may include preheating using a first laser heating head and a second laser heating head. In a further example, preheating may include preheating using a first laser heating head movable in a direction orthogonal to the conveyance direction of the blank and preheating using a second laser heating head downstream of the first laser heating head, and the second laser heating head is movable in a direction orthogonal to the conveyance direction of the blank.

[0024] In some examples, the preselected region may include a region where the thickness of the blank is increased. The heating time in the furnace can be shortened, and the length of the furnace can be shortened. The heating process can be improved.

[0025] In some examples, preheating can be performed in 10 seconds or less.

[0026] In some examples, the preheating step may include heating at least a preselected region of the blank to a temperature below the Ac3 temperature, specifically 300 - 820 °C, more specifically 500 - 700 °C.

[0027] In a further aspect, a heating system for heating a blank in a production line is provided. The heating system includes a furnace, a conveyor system for conveying the blank through the furnace, and a preheating system for preheating one or more preselected regions of the blank while the blank is being conveyed towards the furnace. The preheating system is disposed upstream of the furnace and includes one or more laser heating heads.

Brief Description of the Drawings

[0028] Hereinafter, non-limiting examples of the present disclosure will be described with reference to the accompanying drawings. [Figure 1] FIG. 1 is a flowchart of a method for manufacturing a component from a blank. [Figure 2] FIG. 2 shows a side view of a production line according to an embodiment of the present disclosure. [Figure 3A] FIGS. 3a - 3b show an example of a preheating system. [Figure 3B](the above) [Figure 4A] Figures 4a to 4c schematically show blanks with regions of different thicknesses. [Figure 4B] (the above) [Figure 4C] (the above)

[0029] These figures illustrate exemplary embodiments and are intended solely as aids to understanding the subject matter described in the claims, and do not limit the invention in any way. [Modes for carrying out the invention]

[0030] In these figures, the same reference numerals are used to indicate corresponding components.

[0031] Figure 1 shows a flowchart of a method for manufacturing a part from a blank. This method includes the steps of: placing the blank on a conveyor system and transporting the blank toward a furnace 402; preheating one or more pre-selected areas of the blank while transporting it toward the furnace 404; and transporting the blank through the furnace 406, where preheating includes laser heating of pre-selected areas of the blank using one or more laser heating heads.

[0032] In step 402, the blanks may be placed on a conveyor system, for example, by an industrial transport robot. In some examples, the blanks may have different thicknesses. The blanks may be manufactured from ultra-high-strength steel or aluminum.

[0033] In step 404, the blank may be preheated while being transported toward the furnace, for example, via conveyor rollers, parallel conveyor belts, or walking beams. In step 404, preheating includes laser heating a pre-selected area of ​​the blank using one or more laser heating heads. In some examples, the pre-selected area of ​​the blank may include an area of ​​the blank with increased thickness.

[0034] In some cases, the laser heating head may be a multi-axis laser heating head. In other cases, the laser head may be moved in a direction perpendicular to the blank transport direction.

[0035] Preheating may include preheating by a first laser heating head and a second laser heating head. A pre-selected area of ​​the blank may be heated to below Ac3 temperature, specifically 300-820°C, and more specifically 500-700°C.

[0036] In process 406, the blank is transported through a furnace. Inside the furnace, the blank may be heated above Ac3 temperature. After heating, the heated blank may be discharged from the furnace and transported to a press tool, for example by an industrial transport robot, where it may be hot stamped. The blank may also be hardened whole or partially within the press tool. The die of the press tool may be adequately cooled, for example, by introducing cold water or other cooling means through conduits within the die.

[0037] In some cases, the entire blank / part may be rapidly cooled, i.e., cooled at a rate exceeding the critical cooling rate, so that a martensitic microstructure is obtained substantially throughout the part. In other cases, differential cooling within the mold may create a soft zone within the part. To avoid rapid cooling and to form other microstructures such as bainite, ferrite, pearlite, or mixtures thereof, parts of the mold may be heated. Optionally, the blank may be subjected to further post-processing steps such as cutting, trimming, and / or joining to further parts using welding, for example.

[0038] Figure 2 shows a blank 300 in production line 100. The process described in Figure 1 can be carried out on a production line like the one shown in Figure 2.

[0039] The production line 100 may be a hot deformation or hot stamping production line, which may include, for example, a conveyor system 120 for transporting blanks 300 through the production line 100. The conveyor system 120 may include, for example, multiple conveyor rollers, parallel conveyor belts, or walking beams. In such a case, the conveyor system 120 may be driven using, for example, a motor. In this case, the speed of the conveyor system 120 may be controlled by controlling the speed of the motor.

[0040] For example, the conveyor system 120 may include a supply system for placing blanks onto the conveyor system and a furnace conveyor system for transporting the blanks through the furnace.

[0041] As shown in Figure 2, the blank 300 is placed on the conveyor system 120 and transported toward the furnace 130. The blank may be placed on the conveyor system by an industrial transport robot after being cut, for example, from a steel strip coil.

[0042] In the production line 100, one or more pre-selected areas of the blank are preheated while the blank is being transported toward the furnace. Preheating is performed by a preheating system 110 and includes laser heating of the pre-selected areas of the blank using one or more laser heating heads. In some examples, the preheating system 110 may comprise one or more laser heating heads housed in a laser cell 113 located upstream of the furnace.

[0043] Rapid and precise heating of a pre-selected area of ​​the blank can be ensured by preheating using one or more laser heating heads. In addition, laser heating allows heating of areas of the blank that cannot be easily heated by other heating techniques, such as infrared heating, due to the shape and / or size of the blank.

[0044] After preheating, the blank 300 is transported through the furnace 130, where it may be heated to a predetermined temperature, such as the austenitizing temperature, to prepare the blank 300 for subsequent processes. In particular, the blank may be heated to above Ac3.

[0045] The furnace temperature and the time the blank remains in the furnace can vary depending on the blank material and the blank's coating. If the blank is subjected to a preheating process, the time spent in the furnace can be reduced compared to the time spent in the furnace for blanks that have not undergone preheating. In particular, the furnace time can be extended to ensure that the thickest parts of the blank are fully austenitized. Preheating these thickest parts reduces the overall furnace time, allowing for the maintenance of high throughput in the production line.

[0046] The heated blank 300 can be discharged from the furnace 130 through a door (not shown) configured to open when the blank 300 arrives and close again when the blank 300 has left the furnace 130. The blank 300 can be transported by a conveyor system 120, for example, a conveyor belt or roller conveyor, to a centering system (for example, a centering table) and precisely positioned for subsequent processing.

[0047] The centering table may be equipped with multiple centering pins that can be moved passively or actively in order to precisely position and center the blank 300.

[0048] After being centered and precisely positioned, the blank 300 may be transported to a press tool for deformation and hardening. The blank 300 may be transported to the press tool by a transport system, for example, one or more industrial transport robots, which may pick up the blank 300 from the conveyor system 120 and place it on the press tool. The transport robot may have multiple gripping units for grasping and picking up the blank 300 from the conveyor means 120.

[0049] As mentioned above, the press tool may be provided with cooling means (not shown) for quenching the blank 300 simultaneously with the hot deformation process, such as a water supply or other suitable means. Cooling or quenching can be performed uniformly over the entire blank 300. Typically, channels for the flow of cold water or other liquid can be provided in the die of the press tool. This cools the contact surface of the press tool and quenches the blank.

[0050] Figures 3a and 3b show a preheating system 110 according to an example of the present disclosure. The preheating system 110 is located upstream of the furnace and comprises one or more laser heating heads 111. In the preheating system, the blank 300 is preheated while being transported toward the furnace.

[0051] Using laser heating allows for rapid preheating of specific (pre-selected) areas of a blank, while maintaining high throughput of the heating system. For example, preheating of specific areas of large blanks, such as blanks with a length and width of 1-2 meters (m), can be achieved quickly and efficiently. In some cases, preheating of one or more pre-selected areas of a blank can be completed in 15 seconds, specifically within 10 seconds.

[0052] The laser heating head can be housed within a support structure 112. In some examples, the laser heating head 111 can move along the support structure 112, for example, via rails or along appropriate guides. The position of the laser heating head can be adjusted according to the location of a pre-selected area of ​​the blank. This ensures that any area of ​​the blank reaches and is preheated by the laser heating head, regardless of the size and shape of the blank. In some examples, the laser heating head 111 can be housed within a laser cell 113 (shown in Figure 2). The laser cell may include a protective housing to prevent the laser beam from being emitted to the outside.

[0053] In some examples, the laser heating head 111 may be moved perpendicular to the direction of blank transport. One or more guides or rails may extend across the conveyor, the laser may move laterally relative to the direction of blank transport, and the laser heating process can be adjusted to the needs of different blanks and / or different areas of the blanks. In some examples, multiple lasers may be mounted on the same guide or rail. In other examples, each guide or rail mounts an individual laser.

[0054] In some examples, the laser heating head may be a multi-axis laser heating head. The direction of the laser beam can be adjusted by rotating the laser head. In some examples, the laser heating head may have appropriate optical means for changing the spot size.

[0055] Furthermore, in some examples, the output of the laser heating head 111 can be adjusted so that the amount of heat supplied by the laser heating head is controlled and different heating temperatures can be achieved. For example, the laser output can be varied between 3 and 15 kW. The preheating process may include heating at least a pre-selected area of ​​the blank to below the Ac3 temperature, for example, between 300 and 820°C. In some examples, a pre-selected area of ​​the blank may be preheated to a temperature between 500 and 700°C.

[0056] Preheating may include preheating using a first laser heating head and a second laser heating head. In some examples, the first laser heating head may heat a first pre-selected area of ​​the blank, and the second laser heating head may heat a second pre-selected area of ​​the blank. In other examples, the first and second laser heating heads may heat the same pre-selected area of ​​the blank. The second laser heating head may be positioned downstream of the first laser heating head. Rapid and precise heating of the pre-selected area of ​​the blank can be achieved.

[0057] In some examples, the preheating system 110 may include a first laser heating head that is movable in a direction perpendicular to the blank transport direction, and a second laser heating head located downstream of the first laser heating head and also movable in a direction perpendicular to the blank transport direction.

[0058] Furthermore, preheating may include preheating only a pre-selected region 360 of the blank. By preheating only a pre-selected region of the blank, the overall heating time in the furnace can be reduced, meaning the blank can reach the target temperature in a shorter time, and the overall heating process can be optimized.

[0059] In some cases, the blank may be formed from multiple blanks or subblanks joined together.

[0060] Figures 4a–4c show examples of blanks containing regions of different thicknesses. In these examples, the blank is formed by multiple subblanks.

[0061] As shown in Figures 4a-4b, an example of a blank having regions of different thicknesses may be a blank formed by multiple subblanks joined together by forming one or more overlapping regions. In such an example, the blank may have increased thickness in one or more overlapping regions compared to the rest of the blank. The overlapping regions may be located in areas where specific strength or strength may be required, such as for impact absorption.

[0062] In the example, each subblank may have a thickness of 0.8 to 2 mm, for example, 1.2 mm. If both subblanks have a thickness of 1.2 mm, the thickness of the overlapping region may be 2.4 mm.

[0063] In some examples, preheating a pre-selected region 360 of the blank with one or more laser heating heads 111 may include preheating at least one overlapping region 350 of the blank 300. In other examples, preheating a pre-selected region 360 of the blank with one or more laser heating heads 111 may include preheating all overlapping regions of the blank.

[0064] Specifically, for example, large blanks with a length and width of 1 to 2 meters or more can be efficiently heated using the system and method described herein. In some examples, blanks with overlapping regions may include blanks that, after formation, could become at least one of the following: a vehicle's integrated roof ring, vehicle's integrated rear ring, vehicle's integrated door ring, vehicle's integrated firewall panel, vehicle's battery box protection frame, and vehicle's integrated bumper beam assembly. The overall heating process can be improved, and high throughput can be achieved in the hot stamping production line.

[0065] Figure 4a shows an example of a blank before it is deformed to form a one-piece roof ring for a vehicle. As shown in Figure 4a, the one-piece roof ring can be made from four subblanks: a first subblank 310, a second subblank 320, a third subblank 330, and a fourth subblank 440, where the first and second subblanks 310, 320 may be longitudinal beam blanks, and the third and fourth subblanks 330, 340 may be transverse beam blanks. The longitudinal beam blanks may be joined to the front transverse beam blank and the rear transverse beam blank to form a substantially closed ring shape. The blanks can be joined to each other, for example, by laser welding or spot welding.

[0066] Subblanks can be joined to one another by partially overlapping them to form one or more overlapping regions 350. That is, one subblank is simply partially placed on top of another subblank, and then the subblanks are joined to each other. Thus, the overlapping region acquires an increased thickness compared to the rest of the blank. Such an increase in thickness can be used to adjust the mechanical properties as needed, for example, to provide localized reinforcement in areas where improved strength and / or rigidity is required.

[0067] One or more of the overlapping regions 350 may be pre-selected regions 360 of the blank that are preheated while the blank is being transported toward the furnace. The overlapping regions 350 may be heated by the same laser heating head or by different laser heating heads.

[0068] When a blank is being transported toward a furnace, the blank may have overlapping regions located further upstream in the transport direction and overlapping regions located further downstream in the transport direction. In this particular example, the overlapping region located upstream of the blank may be an overlapping region formed by partially overlapping a third sub-blank 330 with the first and second sub-blanks 310, 320. These overlapping regions may be heated by a first laser heating head. Furthermore, the overlapping region located further downstream in this example may be an overlapping region formed by partially overlapping a fourth sub-blank 340 with the first and second sub-blanks 310, 320, and may be heated by a second laser heating head located downstream of the first laser heating head. For example, the first laser heating head may be mounted to be movable along a first guide or rail extending across the transport direction, and the second laser heating head may be movable along a second guide or rail extending across the transport direction but located further downstream in the transport direction.

[0069] In a further example, one of the two laser heating heads may subsequently heat the left portion of the blank to be heated, while the other laser heating head subsequently heats the right portion of the blank to be heated.

[0070] Furthermore, as shown in Figure 4a, the patch blank 370 may be joined to at least one of the multiple subblanks that form the blank 300. A patch blank can be considered here as a blank that completely overlaps another blank, that is, a patch blank can be completely positioned around another blank. A patch blank may be joined to another blank by welding, for example, spot welding or remote laser welding. The resulting combination of a “base” blank and a patch blank is often called a “patchwork blank.”

[0071] To increase the strength of a specific area of ​​the blank 300, a patch blank 370 can be added as reinforcement. The overlapping area formed by overlapping the patch blank 370 with another blank will have increased thickness compared to the rest of the blank. In some examples, preheating one or more pre-selected areas of the blank may include preheating the area of ​​the blank containing the patch blank.

[0072] The overlapping region of the blank includes the region of the blank with increased thickness. In some examples, preheating a pre-selected region 360 of the blank may include preheating at least one overlapping region of the blank 300. In other examples, preheating a pre-selected region of the blank may include preheating all overlapping regions of the blank 300, for example, the overlapping region formed by the partial overlapping of the blanks and the region containing the patch blank.

[0073] Figure 4b shows another example of a blank having regions of different thicknesses. Figure 4b shows the blank before it is deformed to form the integrated body side structural frame of the vehicle. The blank in Figure 4b is formed by joining two subblanks, namely a first subblank 310 and a second subblank 320. The first subblank 310 and the second subblank 320 partially overlap in an overlapping region 350. In this example, the upper part of the first subblank 310 is laser-welded edge-to-edge to the second subblank 320 via a weld line 19.

[0074] In the example shown in Figure 4b, the first subblank 310 and the second subblank 320 are spot-welded through an overlapping region 350. In this particular example, the overlapping region 350 is located at the bottom of the first blank 10. The top of the first blank 310 may be laser-welded to the second blank 320 via a laser welding line 19.

[0075] In this example, a pre-selected region 360 of the blank that is preheated when the blank is transported to the furnace may be an overlapping region 350 that is thicker than other regions of the blank. The blank 300 may be transported via a conveyor system, and the overlapping region 350 of the blank may be preheated by one or more laser heating heads. Inside the furnace, the blank 300 can reach a predetermined temperature in a shorter time.

[0076] Figure 4c schematically shows another example of a blank containing regions of different thicknesses. For example, floor panels can be hot-stamped from such a blank.

[0077] As shown in Figure 4c, the blank 300 may be a tailor-welded blank (TWB) formed by joining multiple subblanks 310, 320 by edge-to-edge welding, such as laser welding.

[0078] Multiple subblanks 310, 320 may consist of different thicknesses and / or different materials. In this particular example, subblank 320 may be thicker than subblank 310. Thus, while blank 300 is being transported toward the furnace, one or more laser heating heads 111 can preheat areas 320 of blank 300.

[0079] One or more laser heating heads can specifically irradiate the thicker regions of the blank, i.e., region 320, with a laser beam, allowing these regions to be preheated quickly and efficiently to the desired temperature. Because the thicker regions of the blank are preheated, the time required to heat the blank in the furnace can be reduced. Blanks with regions of varying thickness may require less heating time in the furnace than blanks with uniform thickness.

[0080] In other examples, multiple subblanks forming a blank, such as a tailor weld blank, may be composed of materials with different specific heat capacities. Therefore, each material may need to be heated for a specific time until it reaches a predetermined temperature. In some cases, preheating one or more pre-selected areas of the blank may involve preheating areas of the blank with higher specific heat capacities. Since the blank can reach the target temperature in a shorter time, the heating time in the furnace can be reduced, and consequently, the furnace length can be decreased.

[0081] In some cases, the blanks or the aforementioned subblanks may be manufactured from ultra-high-strength steel (UHSS). Boron steel, e.g., 22MnB5, or other steel compositions mentioned above, may be suitable UHSS. These blanks, e.g., boron steel blanks, may include an aluminum-silicon coating or a zinc coating.

[0082] Usibor® 1500P is an example of 22MnB5 steel. The composition of Usibor® is summarized in weight percent as follows (the remainder being 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) (%): 0.01~0.1 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

[0083] Usibor® 1500P may have, for example, a yield strength of 1100 MPa and a tensile strength of 1500 MPa.

[0084] Usibor® 2000 is an example of 37MnB5 steel, another boron steel with even higher strength. Usibor® 2000 can have a yield strength of 1400 MPa or higher, and a tensile strength exceeding 1800 MPa. The composition of Usibor® 2000 is summarized by weight percentage as follows (the remainder being 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) (%): 0.01~0.06 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

[0085] MBW-K(registered trademark)1900 is a ThyssenKrupp product. TM This is a manganese-boron steel 34MnB4, suitable for hot stamping and the methods disclosed herein, with an ultimate tensile strength of 1900 MPa after stamping. The chemical composition of MBW-K(registered trademark) 1900 is summarized in weight percent as follows: Maximum carbon (C) (%): 0.38 Maximum silicon (Si) (%): 0.40 Maximum manganese (Mn) (%): 1.40 Maximum phosphorus (P) (%): 0.025 Maximum sulfur (S) (%): 0.010 Minimum aluminum (Al) (%): 0.015 Maximum chromium and molybdenum (Cr+Mo) (%): 0.50 Maximum Titanium (Ti) (%): 0.05 Maximum boron (B) (%): 0.005

[0086] MBW(registered trademark)1900 is ThyssenKrupp TM Another manganese-boron steel is manufactured and may have an ultimate tensile strength of 1900 MPa. It is commercially available with an aluminum-silicon coating and is suitable for hot stamping and the methods disclosed herein. The chemical composition of MBW® 1900 is summarized in weight percent as follows: Maximum carbon (C) (%): 0.38 Maximum silicon (Si) (%): 0.40 Maximum manganese (Mn) (%): 1.40 Maximum phosphorus (P) (%): 0.025 Maximum sulfur (S) (%): 0.010 Minimum aluminum (Al) (%): 0.1 Maximum niobium (Nb) (%): 0.05 Maximum Titanium (Ti) (%): 0.05 Maximum chromium and molybdenum (Cr+Mo) (%): 0.50 Maximum boron (B) (%): 0.005

[0087] B1800HS is yet another boron steel that may have an ultimate tensile strength of approximately 1800 MPa and is suitable for hot stamping and the methods disclosed herein. The chemical composition of B1800HS is summarized in weight percent as follows: Carbon (C) (%): 0.28~0.35 Maximum silicon (Si) (%): 0.5 Manganese (Mn) (%): 1.0~1.8 Maximum phosphorus (P) (%): 0.025 Maximum sulfur (S) (%): 0.010 Aluminum (Al) (%): 0.01~0.06 Maximum Titanium (Ti) (%): 0.05 Maximum boron (B) (%): 0.0050 Maximum chromium, molybdenum, and niobium (Cr+Mo+Nb) (%): 0.80

[0088] Multiple subblanks forming the blank may be made of different materials and / or thicknesses. For example, blanks made of press-hardenable manganese-boron steel such as Usibor® or MBW-K® 1900 (e.g., Usibor® 1500 and / or Usibor® 2000) can be used as subblanks forming the blank. When these types of materials are used in the hot forming and subsequent quenching processes, a martensite structure is mainly obtained due to the influence of Usibor®. One or more of the blanks may be made from different materials such as Ductibor® 1000.

[0089] Ductibor® 1000 is an alternative material used in hot stamping to increase elongation compared to Usibor® 1500 and Usibor® 2000. Ductibor® 1000 can have a yield strength of 800 MPa or higher and an ultimate tensile strength of 1000 MPa or higher. The composition of Ductibor® 1000 is summarized by weight percentage as follows (the remainder being iron (Fe) and impurities): Maximum carbon (C) (%): 0.10 Maximum silicon (Si) (%): 0.6 Maximum manganese (Mn) (%): 1.8 Maximum phosphorus (P) (%): 0.03 Maximum sulfur (S) (%): 0.01 Aluminum (Al) (%): 0.01~0.1 Maximum Titanium (Ti) (%): 0.05 Maximum niobium (Nb) (%): 0.10 Maximum copper (Cu)(%):0.20 Maximum boron (B) (%): 0.005 Maximum chromium (Cr) (%): 0.20

[0090] In other examples, the blank may include aluminum. The aluminum in the blank may be an aluminum alloy selected from the 6000 series and 7000 series aluminum alloys. These series are characterized by their strength, corrosion resistance, and weldability.

[0091] While only a few embodiments are disclosed here, other alternatives, modifications, uses, and / or equivalents thereof are also possible. Furthermore, any possible combination of the embodiments described is also included. Accordingly, the scope of this disclosure should not be limited to any particular embodiment, but should be determined solely by a fair interpretation of the subsequent claims.

Claims

1. In a method for manufacturing parts from blanks, A process of placing a blank (300) onto a conveyor system (120) and transporting the blank toward a furnace (130); A process of preheating one or more pre-selected regions (360) of a blank while transporting it toward a furnace (130); Process of transporting the blank (300) through the furnace (130) A method comprising a preheating step which includes laser heating of a pre-selected area (360) of a blank using one or more laser heating heads (111).

2. The method according to claim 1, wherein the laser heating head (111) is a multi-axis laser heating head.

3. The method according to claim 1 or 2, further comprising moving the laser heating head (111) in a direction perpendicular to the transport direction of the blank.

4. The method according to claim 3, wherein the speed of the laser heating head is varied during operation, particularly depending on a pre-selected area of ​​the blank.

5. The method according to any one of claims 1 to 4, wherein the angle of the laser spot and / or multi-axis laser heating head is varied and adjusted in particular according to a pre-selected area of ​​the blank.

6. The method according to any one of claims 1 to 5, wherein the preheating step includes preheating using a first laser head and a second laser head, the first laser head being positioned upstream of the second laser head.

7. The method according to any one of claims 1 to 6, wherein a pre-selected region includes a region of the blank (320, 350) having an increased thickness compared to other regions of the blank.

8. The method according to any one of claims 1 to 7, wherein preheating is performed within 10 seconds.

9. The method according to any one of claims 1 to 8, wherein the preheating step includes heating at least a pre-selected region (360) of the blank to below an Ac3 temperature, particularly between 300 and 820°C, and more specifically between 500 and 700°C.

10. The method according to any one of claims 1 to 9, wherein the furnace heats the blank until the temperature exceeds Ac3.

11. The process of transferring the heated blank to a press tool; The process of hot stamping a blank; and The process of rapidly cooling the blank The method according to any one of claims 1 to 10, further comprising:

12. In a heating system for heating blanks on a production line, Furnace (130); A conveyor system (120) for transporting blanks through a furnace (130); and A preheating system (110) for preheating one or more pre-selected regions (360) of a blank (300) while the blank (300) is being transported toward a furnace (130), the preheating system (110) being positioned upstream of the furnace (130) and comprising one or more laser heating heads (111). A heating system equipped with the following features.

13. The heating system according to claim 11, wherein the laser heating head (111) is a multi-axis laser heating head.

14. The heating system according to any one of claims 11 to 12, wherein the preheating system (110) comprises a first laser heating head that is movable in a direction perpendicular to the direction of transport of the blank.

15. The heating system according to claim 13, wherein the preheating system comprises a second laser heating head downstream of a first laser heating head, and the second laser heating head is movable in a direction perpendicular to the blank transport direction.

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