Method for cold stamping a workpiece of ultra-high strength steel sheet

Abstract

The application discloses a cold stamping manufacturing method of an ultrahigh-strength steel plate workpiece, which mainly comprises the following steps: planning a desired appearance shape of a steel plate and a predetermined included angle, preparing an ultrahigh-strength steel plate with a strength of 980 MPa or above, a stamping die and a forming die, then cold stamping the steel plate by using the stamping die to form an initial workpiece, cold stamping the initial workpiece by using the forming die after the elastic rebound of the initial workpiece to form a steel plate workpiece, and the shape and the included angle of the steel plate workpiece are consistent with the appearance shape and the predetermined included angle of the steel plate, finally taking out the steel plate workpiece from the forming die, so that the direct implementation of the cold stamping method can quickly and effectively stamp the ultrahigh-strength steel plate into the ultrahigh-strength steel plate workpiece, and any heating treatment is not needed, which is helpful to energy saving and carbon reduction.

Description

Technical Field

[0001] This invention relates to a steel plate forming method, specifically to a cold stamping manufacturing method for ultra-high strength steel plate workpieces. Background Technology

[0002] In recent years, due to heightened awareness of environmental issues, automakers have not only focused on lightweighting vehicle bodies to improve fuel efficiency, but have also developed a need to increase the strength of vehicle bodies to ensure crash safety. In order to balance lightweighting and crash safety, ultra-high strength steel sheets (strength greater than 980MPa) are used as vehicle body materials. However, the higher the strength of the steel sheet, the more difficult it is to press and form. This is because the higher the strength of the steel sheet, the lower its ductility, bending and expansion properties, and there will be springback after processing. All these factors make it difficult to process and form the steel sheet.

[0003] According to a report by the World Steel Association, using advanced high-strength steel (AHSS) can achieve a weight reduction of over 40% in vehicle bodies, thus achieving lightweighting. European automakers are also committed to research and development in materials and technologies. For example, in 2023, over 50% of Volvo's XC90 models used ultra-high-strength steel exceeding 980MPa, and over 35% used steel with a strength of 1.5GPa (i.e., 1500MPa). In particular, for 1.5GPa strength products, boron steel is currently the main material, and hot stamping technology is used to overcome the springback characteristics of the material. Phase transformation is used to increase the strength of the formed parts. However, the material has special composition requirements and high cost, resulting in high production costs. Furthermore, because the processing of ultra-high-strength steel sheets is prone to problems such as low ductility, low bending, and springback after processing, in practice, cold stamping has not yet been seen to process ultra-high-strength steel sheets.

[0004] Current hot stamping processes primarily involve heating steel plates with an initial strength of 500–600 MPa to 880–950°C, then stamping the steel plate in a mold to form the appearance of a part while maintaining pressure. Afterward, the steel plate is removed and rapidly quenched at a cooling rate of 20–300°C / s. Because the cooling process transforms the steel plate's microstructure from austenite to martensite, the strength of the cooled part can reach or exceed 1500 MPa. However, the heating operation in this hot stamping process consumes a significant amount of energy and also generates carbon dioxide. Specifically, for high-temperature heating operations above 900°C, this heating accounts for approximately 91% of the carbon emissions in the process. Overall, this hot stamping process is difficult to achieve in terms of energy and carbon reduction. Therefore, how to effectively process this ultra-high-strength steel plate while simultaneously achieving energy-saving and carbon-reducing advantages is a goal that the industry is striving to achieve. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a cold stamping manufacturing method for ultra-high strength steel plate workpieces, which uses cold stamping at room temperature to form an ultra-high strength steel plate, achieving not only fast and efficient steel plate processing, but also contributing to energy conservation and carbon reduction.

[0006] Therefore, the cold stamping manufacturing method for ultra-high strength steel plate workpieces of the present invention includes a preparation step, a stamping step, a shaping step, and a material handling step. The preparation step includes a planning operation, pre-setting a desired steel plate shape, the steel plate shape having a bottom surface and a side surface, and a predetermined angle formed between the bottom surface and the side surface. The preparation step also includes a material preparation operation, preparing an ultra-high strength steel plate with a strength of not less than 980 MPa, a stamping die with a stamping die head, and a forming die with a forming die head. The stamping die is used to reduce the springback of the ultra-high strength steel plate after stamping, and the forming die is used to eliminate springback so that the ultra-high strength steel plate is formed into the desired steel plate shape. The stamping die head has a stamping end surface and a stamping side surface connected to the stamping end surface, and a stamping die angle is formed between the stamping side surface and the stamping end surface. The angle is less than the predetermined angle and the difference between the two angles is not less than 30 degrees; the forming die has a forming end face and a forming side face connected to the forming end face, and a forming die angle is formed between the forming end face and the forming side face, and the forming die angle is equal to the predetermined angle; in the stamping step, the stamping die is used to cold stamp the ultra-high strength steel plate to form an initial workpiece, so that the initial workpiece has an initial bottom face and an initial side face, and the initial angle formed between the initial side face and the initial bottom face is less than the predetermined angle, which helps to reduce the springback of the initial workpiece during processing; in the shaping step, the forming die is used to cold stamp the initial workpiece to form a steel plate workpiece, and the condition that the forming die angle is equal to the predetermined angle makes the shape of the steel plate workpiece conform to the set appearance shape of the steel plate; finally, the unloading step removes the steel plate workpiece from the forming die, thus completing the stamping forming of the steel plate workpiece.

[0007] As a further improvement of the present invention, the material preparation operation in the preparatory step is provided with a second mold. The second mold includes a second die head and a second bottom die disposed opposite to the second die head. The second bottom die has a second stamping groove. The second die head has a second end face and a second side face connected to the second end face. A second included angle is formed between the second side face and the second end face. The second included angle is smaller than the predetermined included angle but larger than the die included angle. An additional stamping step is added between the stamping step and the shaping step. The additional stamping step places the initial workpiece obtained in the stamping step into the second stamping groove and uses the second die head to move towards the second stamping groove to perform cold stamping on the initial workpiece. After the initial workpiece has undergone the additional stamping step, it is moved to the forming groove to perform the shaping step.

[0008] As a further improvement of the present invention, the composition of the ultra-high strength steel plate includes, by weight percentage, 0.1% to 0.38% carbon, 1% to 2.10% manganese, not more than 0.18% phosphorus, 0.1% to 0.57% silicon, not more than 0.005% sulfur, and the remainder being iron and other unavoidable components.

[0009] As a further improvement of the present invention, the radius of the fillet formed at the connection between the stamped side surface and the stamped end surface does not exceed 6 mm.

[0010] As a further improvement of the present invention, the side portion of the steel plate's external shape includes two side portions, and a plurality of the side portions extend outward from the bottom portion; the stamped side portion includes two stamped side portions, and a plurality of the stamped side portions extend outward from the stamped end portion; the formed side portion includes two formed side portions, and a plurality of the formed side portions extend outward from the formed end portion; the initial side portion includes two initial side portions, and a plurality of the initial side portions extend outward from the initial bottom portion; the steel plate workpiece has a workpiece bottom portion and two workpiece side portions extending outward from the workpiece bottom portion.

[0011] As a further improvement of the present invention, the second side portion includes two second side portions, and a plurality of the second side portions extend outward from the second end portion.

[0012] By implementing the above steps in sequence, no heating operation is required during the stamping process of the steel plate. Therefore, it is possible to quickly and effectively stamp out the steel plate workpiece with ultra-high strength, and also achieve the effect of energy saving and carbon reduction. Attached Figure Description

[0013] Figure 1 This is a flowchart of the first preferred embodiment of the present invention.

[0014] Figure 2This is a schematic diagram illustrating the implementation of the planning operation in the first preferred embodiment.

[0015] Figure 3 This is a structural schematic diagram of the stamping die and forming die of the first preferred embodiment.

[0016] Figure 4 This is a schematic diagram illustrating the material preparation and stamping steps of the first preferred embodiment.

[0017] Figure 5 This is a schematic diagram illustrating the shaping and material handling steps of the first preferred embodiment.

[0018] Figure 6 This is a flowchart of the second preferred embodiment of the present invention.

[0019] Figure 7 This is a schematic diagram illustrating the implementation of the additional stamping step in the second preferred embodiment.

[0020] Symbol explanation:

[0021] (This invention)

[0022] 3: Cold stamping manufacturing method for ultra-high strength steel plate workpieces

[0023] 31: Preparatory Steps

[0024] 31A: Planning Operations

[0025] 31B: Material Preparation Operations

[0026] 32: Stamping Steps

[0027] 33: Plastic Surgery Steps

[0028] 34: Material Retrieval Steps

[0029] 35: Additional stamping steps

[0030] 4: Ultra-high strength steel plate

[0031] 5: Steel plate workpiece

[0032] 6: Stamping Dies

[0033] 7: Molding mold

[0034] 8: Second mold

[0035] 41: Bottom surface

[0036] 42: Side profile

[0037] 42': Side view

[0038] 40: Initial workpiece

[0039] 401: Initial bottom surface

[0040] 402: Initial side profile

[0041] 402': Initial side view

[0042] 51: Bottom surface of the workpiece

[0043] 52': Side of the workpiece

[0044] 61: Stamping Die

[0045] 62: Stamping bottom die

[0046] 71: Forming die head

[0047] 72: Molding bottom mold

[0048] 81: Second mold head

[0049] 82: Second bottom mold

[0050] 611: Stamping end face

[0051] 612: Stamped side part

[0052] 612': Stamped side

[0053] 621: Stamping groove

[0054] 711: Molded end face

[0055] 712: Molded side surface

[0056] 712': Molded side

[0057] 721: Forming groove

[0058] 811: Second end face

[0059] 812: Second side profile

[0060] 812': Second side

[0061] 821: Second stamping groove

[0062] 4a: Predetermined included angle

[0063] 40a: Initial included angle

[0064] 5a: Workpiece included angle

[0065] 61a: Die included angle

[0066] 61r: Corner radius

[0067] 71a: Molding die included angle

[0068] 81a: Second included angle Detailed Implementation

[0069] The foregoing and other technical contents, features and effects of the present invention will become clear from the following detailed description of the preferred embodiments with reference to the accompanying drawings.

[0070] See Figure 1 The first preferred embodiment of the present invention is a cold stamping manufacturing method 3 for ultra-high strength steel plate workpieces, wherein a cold stamping means is used to process an ultra-high strength steel plate 4, and the processed ultra-high strength steel plate 4 is formed into an ultra-high strength steel plate workpiece 5; the cold stamping manufacturing method 3 sequentially includes a preparation step 31, a stamping step 32, a shaping step 33, and a material handling step 34; the preparation step 31 includes a planning operation 31A and a material preparation operation 31B, wherein the planning operation 31A is for pre-setting the appearance shape of a steel plate to be formed, such as Figure 2 As shown, the steel plate has a bottom portion 41 and a side portion 42 connected to the bottom portion 41. A predetermined angle 4a is formed between the side portion 42 and the bottom portion 41. In this embodiment, the side portion 42 may include two side portions 42', and multiple side portions 42' extend outward from the bottom portion 41. Therefore, each side portion 42' forms a predetermined angle 4a with the bottom portion 41. (See also...) Figure 3 The material preparation operation 31B includes an ultra-high strength steel plate 4, a stamping die 6, and a forming die 7, and if... Figure 4 The ultra-high strength steel plate 4 shown in (a) refers to the ultra-high strength steel plate 4 having a strength of not less than 980 MPa, that is, a strength equal to or greater than 980 MPa, and the ultra-high strength steel plate 4 being able to extend to a certain length.

[0071] The stamping die 6 includes a stamping die head 61 and a stamping bottom die 62 opposite to the stamping die head 61, on which a stamping groove 621 is recessed. The stamping die head 61 has a stamping end face 611 and a stamping side face 612 connected to the stamping end face 611. A die angle 61a is formed between the stamping side face 612 and the stamping end face 611. In this embodiment, the stamping side face 612 may include two stamping side faces 612', and multiple stamping side faces 612' extend outward from the stamping end face 611. Therefore, each stamping side face 612' forms a die angle 61a with the stamping end face 611. Furthermore, the die angle 61a is smaller than the outer shape of the steel plate. A predetermined included angle 4a is provided, and the value of the die included angle 61a differs from the value of the predetermined included angle 4a by no less than 30 degrees, that is, the difference between the two included angles is 30 degrees or more than 30 degrees. Preferably, the difference is 45 degrees. For example, when the planned predetermined included angle 4a is 120 degrees, the die included angle 61a does not exceed 90 degrees, and 75 degrees is particularly preferred as the die included angle 61a. In addition, a fillet radius 61r is defined at the connection between the stamping side surface 612 and the stamping end surface 611. The fillet radius 61r preferably does not exceed 6 mm, that is, it is equal to or less than 6 mm (≦6 mm). Therefore, the above conditions can help reduce the amount of springback and slow down the degree of springback, so that the ultra-high strength steel plate 4 can be successfully stamped in subsequent steps.

[0072] See also Figure 3 The molding die 7 has a molding die head 71 and a molding bottom die 72 disposed opposite to the molding die head 71 and having a molding groove 721 recessed thereon. The molding die head 71 has a molding end face 711 and a molding side face 712 connected to the molding end face 711. At the same time, a molding die included angle 71a is formed between the molding side face 712 and the molding end face 711. The molding die included angle 71a is equal to a predetermined included angle 4a of the appearance shape of the steel plate. In this embodiment, the molding side face 712 may include two molding side faces 712'. Multiple molding side faces 712' extend outward from the molding end face 711, so each molding side face 712' and the molding end face 711 form a molding die included angle 71a.

[0073] To achieve cold stamping, in this embodiment, the composition of the ultra-high strength steel plate 4 may include, by weight percentage, 0.1% to 0.38% carbon, 1% to 2.10% manganese, no more than 0.18% phosphorus, 0.1% to 0.57% silicon, no more than 0.005% sulfur, with the remainder being iron and other unavoidable components. The composition can be adjusted according to the strength of the ultra-high strength steel plate 4, i.e., the content of carbon, manganese, phosphorus, silicon, and sulfur, as listed in Table 1. In this embodiment, a steel plate with a strength of 980 MPa is used as an example.

[0074] Table 1

[0075] Strength (MPa) Carbon (C) Manganese (Mn) Phosphorus (P) Silicon (SI) Sulfur (S) 980 0.10～0.17 1.60～1.70 Below 0.009 0.30～0.40 Below 0.001 1200 0.15～0.25 1.90～2.10 0.012 or less 0.45～0.57 Below 0.005 1300 0.15～0.21 1.50～1.65 Below 0.007 0.30～0.40 0.002 or less 1300 0.22～0.25 1.15～1.35 Below 0.015 0.15～0.25 0.002 or less 1400 0.16～0.25 1.60～1.65 Below 0.009 0.15～0.30 Below 0.001 1400 0.26～0.38 1.15～1.30 Below 0.018 0.30～0.40 0.003 or less 1500 0.20～0.25 1.07～1.12 Below 0.015 0.18～0.23 Below 0.001 1500 0.34～0.38 1.15～1.30 Below 0.018 0.20～0.30 0.003 or less 1500 0.25～0.30 1.65～1.70 Below 0.015 0.20～0.30 Below 0.004 1700 0.30～0.38 1.00～1.05 Below 0.010 0.2～0.25 Below 0.001

[0076] See Figure 3 and related references Figure 4 , Figure 5 The process of cold stamping a steel sheet workpiece 5 first involves stamping step 32, which involves stamping a high-strength steel sheet 4 (such as...) to be processed. Figure 4 As shown in (a), the steel plate 4 is placed in the stamping groove 621 of the stamping die 62, and then the stamping die head 61 moves toward the stamping groove 621. When the stamping end face 611 and the stamping side face 612 of the stamping die head 61 enter the stamping groove 621, the steel plate 4 is directly stamped by the stamping die head 61 at room temperature, and the stamped part moves toward the interior of the stamping groove 621. In this way, the shape of the ultra-high strength steel plate 4 can be changed to form an initial workpiece 40 (such as...). Figure 4 As shown in (b); the initial workpiece 40 has an initial bottom portion 401 and an initial side portion 402 connected to the initial bottom portion 401, and the initial included angle 40a formed between the initial side portion 402 and the initial bottom portion 401 is smaller than the predetermined included angle 4a. In this embodiment, the initial side portion 402 includes two initial side portions 402', and a plurality of initial side portions 402' extend outward from the initial bottom portion 401 respectively. Therefore, each initial side portion 402' forms an initial included angle 4a with the initial bottom portion 401. Therefore, after the initial workpiece 40 is formed by cold stamping the ultra-high strength steel plate 4 with the stamping die 6, the initial side portion 402 of the initial workpiece 40 produces a slight elastic recovery (e.g. Figure 4 (See arrow (c)); after the stamping die head 61 exits the stamping bottom die 62, the initial workpiece 40 is then removed from the stamping groove 621. After the initial workpiece 40 leaves the stamping die 6, the initial side portion 402 will experience partial springback, that is, the initial side portion 402 will experience elastic recovery to some extent (e.g., Figure 4(d) The dashed line in the figure shows, for example, when the initial workpiece 40 is just stamped in the stamping groove 621, the initial included angle 40a is initially about 90 degrees (as shown by the dashed line in the figure). Figure 4 As shown in (c), after the initial workpiece 40 is removed from the stamping groove 621, the initial included angle 40a of the initial workpiece 40 may spring back and become 100 to 120 degrees (as shown in (c)). Figure 4 (as shown in (d)).

[0077] See Figure 5 This can be achieved by the shaping step 33, which occurs after the initial side surface 402 of the initial workpiece 40 has elastically recovered (e.g., Figure 5 As shown in (a), the initial workpiece 40 is then moved into the forming groove 721 of the forming bottom mold 72 (as shown in (a)). Figure 5 As shown in (b), the forming die 71 moves directly towards the forming groove 721 to cold stamp the initial workpiece 40, so that the initial workpiece 40 is stamped by the forming die 71 to form a steel plate workpiece 5; in addition, the forming of the steel plate workpiece 5 is limited by the shape of the forming groove 721, and the shape of the stamped steel plate workpiece 5 conforms to the forming end face 711 and the forming side face 712 of the forming die 71, that is, the appearance of the steel plate workpiece 5 will form a workpiece bottom face 51 and a workpiece side face 52, and also form a workpiece angle 5a equal to the forming die angle 71a (e.g., Figure 5 As illustrated in (c), the side portion 52 of the workpiece may have two side portions 52' extending outward from the bottom portion 51 of the workpiece, such that each side portion 52' and the bottom portion 51 of the workpiece form a workpiece angle 5a; therefore, by the cold stamping of the forming die 7, and the forming die angle 71a being equal to the predetermined angle 4a, the shape of the steel plate workpiece 5 is made to conform to the appearance shape of the steel plate in the planning operation 31A.

[0078] Finally, in the material handling step 34, the forming die head 71 is first withdrawn from the forming bottom die 72 (e.g., Figure 5 (as shown by arrow (c)), then remove the steel plate workpiece 5 from the forming groove 721 to obtain the complete steel plate workpiece 5 (as shown by arrow (c)). Figure 5 As shown in (d), this completes the cold stamping manufacturing method 3.

[0079] According to the above, the ultra-high strength steel plate 4 is first subjected to the stamping force of the stamping die 6 at room temperature (i.e., stamping step 32). Under the condition that the difference in phase is not less than 30 degrees in the preparatory step 31, the initial included angle 40a of the initial workpiece 40 obtained in the stamping step 32 can be made smaller than the predetermined included angle 4a, thereby helping to reduce the initial springback of the initial workpiece 40. Then, the initial workpiece 40 is cold-stamped using the forming die 7 (i.e., shaping step 33). Under the condition that the included angle 71a of the forming die is equal to the predetermined included angle 4a, the shaping step 33 can have The forming process effectively eliminates the springback of the initial workpiece 40 after its initial springback. That is, at room temperature, the stamping force of the forming die 7 directly shapes the initial workpiece 40 and prevents further elastic springback. In summary, the stamping step 32 mainly helps to reduce springback after stamping, while the shaping step 33 mainly helps to eliminate springback after stamping to overcome the springback characteristics of the initial workpiece 40. Furthermore, no heating is required during the stamping process, which not only achieves rapid stamping but also avoids unnecessary energy consumption due to the absence of heating, thereby contributing to energy conservation and carbon reduction.

[0080] See Figure 6 , Figure 7 The second preferred embodiment of the present invention still includes the preparation step 31, stamping step 32, shaping step 33 and material handling step 34 of the first embodiment, the details of which can be referred to the relevant paragraphs above; in particular, in the second preferred embodiment, the material preparation operation 31B of the preparation step 31 is further provided with a second mold 8, the second mold 8 including a second mold head 81, a second bottom mold 82 disposed opposite to the second mold head 81 and having a second stamping groove 821 recessed thereon, the second mold head 81 having a second end face 811 and a second side face 812 connected to the second end face 811, and a second included angle is formed between the second side face 812 and the second end face 811. 81a, and in this embodiment, the second side surface 812 may include two second side surfaces 812', and a plurality of the second side surfaces 812' extend outward from the second end surface 811 respectively, so each of the second side surfaces 812' and the second end surface 811 forms a second included angle 81a; furthermore, the second included angle 81a is between the predetermined included angle 4a and the die included angle 61a, that is, the second included angle 81a is smaller than the predetermined included angle 4a but larger than the die included angle 61a. For example, when the planned predetermined included angle 4a is 120 degrees and the die included angle 61a of the stamping die 6 is set to 75 degrees, the second included angle 81a of the second die 8 can be set between 76 degrees and 119 degrees.

[0081] In another preferred embodiment, an additional stamping step 35 is added between the stamping step 32 and the shaping step 33. This additional stamping step 35 places the initial workpiece 40 obtained in the stamping step 32 into the second stamping groove 821, and uses the second die head 81 to move towards the second stamping groove 821 to perform another cold stamping on the initial workpiece 40. After undergoing this additional stamping step 35, the initial workpiece 40 is then moved to the forming groove 721 to perform the shaping step 33. Therefore, if the material preparation operation 31B uses ultra-high strength steel plates... 4 (e.g., strength not less than 1400MPa), the stamping force of the stamping step 32 may not be sufficient to effectively reduce the springback characteristics of the initial workpiece 40. Therefore, the additional stamping step 35 can perform cold stamping again to further reduce the springback characteristics of the initial workpiece 40, thereby helping the shaping step 33 to eliminate springback so that the initial workpiece 40 can be directly cold stamped to form the ultra-high strength steel plate workpiece 5. The above stamping process does not require any heating operation, which not only achieves rapid stamping and forming, but also avoids unnecessary energy consumption without heating operation, thereby achieving the effect of energy saving and carbon reduction.

[0082] In summary, the cold stamping manufacturing method for ultra-high strength steel plate workpieces of the present invention mainly includes a stamping step and a forming step, each performing a cold stamping operation. These cold stamping operations are further complicated by specific conditions: the die angle of the stamping die is less than a predetermined angle, and the difference between the die angle and the predetermined angle is not less than 30 degrees; and the forming die angle of the forming die is equal to the predetermined angle. These operations and conditions allow the ultra-high strength steel plate to not only reduce its springback during the forming process from the initial workpiece to the final steel plate workpiece, but also to eliminate it altogether. Therefore, the steel plate workpiece can be stamped and formed effectively and quickly without any heating operation, thus achieving energy and carbon reduction and environmental protection.

[0083] The above description is only for illustrating preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the specification of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A cold stamping manufacturing method for ultra-high strength steel plate workpieces, characterized in that, It includes: A preliminary step includes a planning operation and a material preparation operation. The planning operation pre-defines the desired shape of a steel plate, which has a bottom portion and a side portion connected to the bottom portion, with a predetermined angle between the bottom portion and the side portion. The material preparation operation prepares an ultra-high strength steel plate with a strength of not less than 980 MPa, a stamping die, and a forming die. The stamping die includes a stamping head and a stamping bottom die opposite to the stamping head, the stamping bottom die having a stamping groove, and the stamping head having a stamping end face. The die has a forming end face and a forming side face connected to the forming end face. The forming side face and the forming end face form a die angle, which is smaller than a predetermined angle and the difference between the die angle and the predetermined angle is not less than 30 degrees. The forming die has a forming head and a forming bottom die opposite to the forming head. The forming bottom die has a forming groove. The forming head has a forming end face and a forming side face connected to the forming end face. The forming side face and the forming end face form a die angle equal to the predetermined angle. In a stamping step, the ultra-high strength steel plate is placed in the stamping groove of the stamping die, and the stamping die head moves directly towards the stamping groove to cold stamp the ultra-high strength steel plate, so that the ultra-high strength steel plate is formed into an initial workpiece by the stamping of the stamping die head. The appearance of the initial workpiece after stamping has an initial bottom part and an initial side part connected to the initial bottom part. An initial included angle is formed between the initial side part and the initial bottom part. The initial included angle is smaller than a predetermined included angle. After the stamping die head completes the cold stamping, the stamping die head exits the stamping die, and the initial workpiece is removed from the stamping groove. In a shaping step, after the initial side surface of the initial workpiece elastically recovers, the initial workpiece is moved into the forming groove of the forming mold, and the forming die head moves directly towards the forming groove to perform cold stamping on the initial workpiece. This causes the initial workpiece to be stamped by the forming die head to form a steel plate workpiece. The stamped steel plate workpiece further forms a workpiece angle equal to the forming die angle. Because the forming die angle is equal to the predetermined angle, the shape of the steel plate workpiece conforms to the planned steel plate appearance shape. The first step of material handling involves first removing the forming die head from the forming bottom die, and then taking the steel plate workpiece out of the forming groove, thus completing the cold stamping manufacturing method.

2. The cold stamping manufacturing method for ultra-high strength steel plate workpieces according to claim 1, characterized in that, In the material preparation process of this preparatory step, a second mold is provided. The second mold includes a second die head and a second bottom mold disposed opposite to the second die head. The second bottom mold has a second stamping groove. The second die head has a second end face and a second side face connected to the second end face. A second included angle is formed between the second side face and the second end face. The second included angle is smaller than the predetermined included angle but larger than the die included angle. An additional stamping step is added between the stamping step and the shaping step. In the additional stamping step, the initial workpiece obtained in the stamping step is placed in the second stamping groove, and the second die head is moved towards the second stamping groove to perform cold stamping on the initial workpiece. After the initial workpiece has undergone the additional stamping step, it is moved to the forming groove to perform the shaping step.

3. The cold stamping manufacturing method for ultra-high strength steel plate workpieces according to claim 1, characterized in that, The composition of this ultra-high strength steel plate, by weight percentage, includes 0.1% to 0.38% carbon, 1% to 2.10% manganese, no more than 0.18% phosphorus, 0.1% to 0.57% silicon, no more than 0.005% sulfur, and the remainder being iron and other unavoidable components.

4. The cold stamping manufacturing method for ultra-high strength steel plate workpieces according to claim 1, characterized in that, The radius of the fillet formed at the connection between the stamped side surface and the stamped end surface shall not exceed 6 mm.

5. The cold stamping manufacturing method for ultra-high strength steel plate workpieces according to claim 1, characterized in that, The side portion of the steel plate's external shape includes two side portions, and multiple side portions extend outward from the bottom portion; the stamped side portion includes two stamped side portions, and multiple stamped side portions extend outward from the stamped end portion; the formed side portion includes two formed side portions, and multiple formed side portions extend outward from the formed end portion; the initial side portion includes two initial side portions, and multiple initial side portions extend outward from the initial bottom portion; the steel plate workpiece has a workpiece bottom portion and two workpiece side portions extending outward from the workpiece bottom portion.

6. The cold stamping manufacturing method for ultra-high strength steel plate workpieces according to claim 2, characterized in that, The second side portion includes two second sides, and a plurality of the second sides extend outward from the second end portion.

Images