Forming process and stamping dies for high-strength plate beams

Abstract

This invention proposes a forming process and stamping die for high-strength plate beam components. The forming process includes: A) providing plate beam blanks; B) preforming, stamping out a molded integral component with an external flange at the groove opening, the integral component including a first preform, a second preform, and a reserved shearing strip located at the center of the groove width of the integral component. The first and second preforms beside the reserved shearing strip have low process protrusions or shallow process recesses on their edges; C) flattening stamping, stamping to remove the process protrusions or process recesses; D) blanking and parting, stamping to cut off the reserved shearing strip. The design of the process protrusions or process recesses in this invention significantly reduces the springback value of the blanking edge after the high-strength plate beam blank is blanked into two finished beams, and without the addition of solidification ribs, it enhances its collision safety performance.

Description

Technical Field

[0001] This invention relates to the field of stamping technology, specifically to a forming process and stamping die for high-strength plate beams. Background Technology

[0002] High-strength steel beams are widely used in automobiles and play a crucial role in vehicle safety performance, such as floor beams and body longitudinal beams. During the manufacturing process of high-strength steel beams, the high yield strength of these components makes springback during molding a persistent challenge in the manufacturing industry. This is especially true for beams in the automotive floor area, where collision safety considerations prevent the addition of reinforcing ribs to avoid them becoming impact-inducing ribs, making it even more difficult to control the amount of springback generated during manufacturing.

[0003] Taking the car floor crossbeam as an example, such as Figure 1 , 2 As shown, existing production processes typically employ a one-out-two molding process, that is, first molding one cross-section... A high-strength beam a1 in the shape of a slot is then cut along the center of its slot width to form symmetrical cross-sections. Two crossbeams a2 are formed from a high-strength beam, and after further processing, two finished crossbeams are obtained. Due to the high strength of the high-strength beam a1, CAE calculations show that the pressure required to directly form the upper surface of the high-strength beam a1 into the ideal state is extremely high. Generally, the pressure provided by the forming die's pressure gauge is far less than the ideal value calculated by CAE. Finally, after the high-strength beam a1 is cut into two crossbeams a2, the cut edges of the upper surface of the crossbeams a2 exhibit a wavy springback. This wavy springback phenomenon cannot be compensated for by conventional springback compensation methods, resulting in a failure to improve the quality of the finished crossbeams.

[0004] The patent disclosed in CN102172735A, entitled "A Process for Solving the Twisting Springback Problem in Longitudinal Beam Forming Using Local Deformation," involves machining at least two protrusions, one larger than the other, at the pre-forming station of the longitudinal beam forming mold. The larger end of the protrusion is located inside the side wall of the mold. However, this method, with the protrusions positioned on both sides of the formed longitudinal beam, fails to address the edge springback problem that occurs after cutting high-strength beams. Summary of the Invention

[0005] The purpose of this invention is to provide a forming process and stamping die for high-strength plate beams, thereby reducing springback at the edges of high-strength plate beams by optimizing the stamping process.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a forming process for high-strength plate beams, comprising the following forming steps:

[0007] A. Provide flat plate beam blanks;

[0008] B. Pre-forming: Stamping out a pre-formed integral part, which includes a first pre-formed part and a second pre-formed part. The overall cross-section of the pre-formed integral part is a groove shape with an outward flange at the opening. The first and second preforms are mirror images of each other with the center of the groove width of the integral part as the center of symmetry. The connection between the first and second preforms is a reserved shearing strip. The edges of the first and second preforms next to the reserved shearing strip are pre-set with low process protrusions or shallow process depressions.

[0009] C. Flattening and stamping to remove process protrusions or process depressions;

[0010] D. Punching and parting, punching and shearing off the reserved shearing strip.

[0011] A stamping die for forming high-strength plate beam parts includes a pressure plate holder located above the plate beam blank and a punch located below the plate beam blank. The pressure plate holder has forming blades arranged on both sides along the width direction of the plate beam blank. The pressure plate holder is driven by a nitrogen spring connected to its top. The bottom of the pressure plate holder and the top of the punch have protrusions or recesses that correspond to the process protrusions or process recesses, respectively.

[0012] This invention primarily involves adding a step during the preforming process: pre-setting process protrusions or recesses on the edges of the first and second preforms next to the pre-reserved shear strip, then flattening these protrusions or recesses, and finally punching and separating the beams to obtain the finished crossbeams. The design of these protrusions or recesses significantly reduces the springback value of the punched edges after the high-strength plate beam blank is punched into two finished crossbeams. This effectively suppresses springback and, without the need for hardening ribs during forming, also enhances the collision safety performance of the crossbeams. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of cutting a high-strength beam into two crossbeams in the prior art;

[0014] Figure 2 This is a schematic diagram illustrating the process of processing the slab beam blank into the first and second preformed parts;

[0015] Figure 3 This is a schematic diagram of the plate beam blank before processing in step A;

[0016] Figure 4 This is a schematic diagram of the initial pressing and forming process in step B1;

[0017] Figure 5 This is an isometric view of the pressure feeder;

[0018] Figure 6This is a top view of the molded one-piece component in step B;

[0019] Figure 7 for Figure 6 A schematic diagram of the preforming process at the LL section;

[0020] Figure 8 for Figure 6 A schematic diagram of the material pressing and forming process at the LL section;

[0021] Figure 9 for Figure 6 A schematic diagram of the leveling process at section LL;

[0022] Figure 10 for Figure 6 A schematic diagram showing the completed leveling process at section LL. Detailed Implementation

[0023] See Figure 1-10 The forming process for the high-strength plate beam-like components shown is as follows:

[0024] A. Provide flat plate beam blank 10a1;

[0025] B. Pre-forming: Stamping out the formed integral part 10, which includes a first pre-formed part 11 and a second pre-formed part 12. The overall cross-section of the formed integral part 10 is a groove shape with an outward flange at the opening. The first preform 11 and the second preform 12 are mirror images of each other with the center of the groove width of the molded integral part 10 as the center of symmetry. The connection between the first preform 11 and the second preform 12 is a reserved shearing strip 30. The first preform 11 and the second preform 12 on the side of the reserved shearing strip 30 are pre-set with low process protrusions 20a or shallow process recesses 20b.

[0026] C. Flattening and stamping, stamping to remove process protrusions 20a or process depressions 20b;

[0027] D. Blanking and parting, stamping and shearing off the reserved shearing strip 30.

[0028] In the above scheme, after the plate beam blank 10a1 is stamped into a formed integral part 10, the symmetrical first preform 11 and second preform 12 are obtained by cutting the reserved shear strip 30 at the center of its groove width. Since the plate beam blank 10a1 is a high-strength plate, CAE calculations show that a pressure of 300T is required to achieve one-time forming. However, the existing stamping die can only provide a pressure of about 50T, which is far less than the pressure required by the CAE calculation. Therefore, the forming can only be achieved by the die finally being pressed shut. The pressure plate 50 cannot provide sufficient pressure in the early stage of forming, which will cause large waves to appear on the cut edges of the first preform 11 and the second preform 12 obtained after stamping. Therefore, in order to reduce the springback value of the cut edge, the present invention adds a step in the preforming process, that is, while stamping the integral part 10, process protrusions 20a or process recesses 20b are stamped on the edges of the first preform 11 and the second preform 12 next to the reserved shear strip 30. Then, the process protrusions 20a or process recesses 20b are flattened by stamping again. After stamping and shaping, the final beam product is obtained.

[0029] The process protrusions 20a or process recesses 20b can improve the stress distribution on the surface of the molded integral part 10 during the molding process, thereby effectively reducing the springback value of the cut edges of the first preform 11 and the second preform 12. This process does not add curing ribs to the first preform 11 and the second preform 12, which can simultaneously improve the vehicle's collision safety performance.

[0030] Specifically, the preforming process in step B further includes:

[0031] B1. Preliminary pressing and forming yields a cross-section that is flat in the center and concave on both sides. Transitional forming part (10a2);

[0032] B2. Trimming and punching;

[0033] B3. Lateral shaping to obtain an overall cross-section that is... 10. Shaped integral parts.

[0034] In step B1, the stamping die for preliminary pressing and forming includes a pressure plate 50 located above the plate beam blank 10a1 and a punch 40 located below the plate beam blank 10a1. Forming blades 51 are arranged on both sides of the pressure plate 50 along the width direction of the plate beam blank 10a1. The pressure plate 50 is driven by a nitrogen spring 52 connected to its top. The bottom of the pressure plate 50 and the top of the punch 40 have protrusions or recesses corresponding to the process protrusions 20a or process recesses 20b, respectively. In this scheme, the pressure plate 50 can only press the plate beam blank 10a1 into shape using the forming blades 51. The transition part 10a2 is obtained by shaping it. Step B2 is performed to trim, punch, and stamp out process protrusions 20a or process recesses 20b. Then, the transition part 10a2 is transferred to another set of molds and step B3 is performed to obtain the overall cross-section through side shaping. The shaped integral part 10 is then formed, and then the flat stamping process in step C is performed to remove the process protrusions 20a or process depressions 20b.

[0035] In step B, step B1 cannot be skipped, and the slab beam blank 10a1 cannot be directly stamped into a cross-section in one go. The molded integral part 10 should be shaped properly; otherwise, it will increase the stress accumulation on the external flange and make it easier to produce processing quality defects.

[0036] The specific solution is that the stamping die for the upsetting stamping includes a second pressure plate 50a located above the forming integral part 10 and a second punch 40a located below the forming integral part 10. The pressure surfaces of the second pressure plate 50a and the second punch 40a are flat to perform the upsetting process.

[0037] In areas where reinforcing structures or other functional structures are provided on the surface of the first preform 11 or the second preform 12, the springback value of the adjacent cut edges will be significantly greater than that of other flat areas. To address this distribution pattern, the process protrusions 20a or process recesses 20b described in step B are densely distributed in areas with high springback values ​​along the edges of the first preform 11 and the second preform 12, and sparsely distributed in areas with low springback values. This arrangement makes the overall springback distribution of the board surface more balanced and stable.

[0038] In order to obtain two crossbeams with identical molding quality, the process protrusions 20a or process recesses 20b described in step B are symmetrically distributed on the bottom surface of the groove of the molded integral part 10 relative to the reserved shear band 30.

[0039] As a preferred embodiment, the process protrusions 20a and process recesses 20b on the edges of the first preform 11 and the second preform 12 are alternately distributed in the length direction of the reserved shear strip 30, which can further improve the stress distribution on the plate surface during the molding process.

[0040] Preferably, in step B, the diameter of the process protrusion 20a or process recess 20b is 10mm, and the distance between two adjacent process protrusions 20a or process recesses 20b distributed along the reserved shear band 30 is 30mm. The shape of the process protrusion 20a or process recess 20b is a hollow spherical crown.

[0041] The process protrusions 20a or process recesses 20b are linearly distributed along the edges of the first preform 11 and the second preform 12. In areas with high springback values ​​along the edges of the first preform 11 and the second preform 12, the process protrusions 20a or process recesses 20b are arranged in two rows. The linear distribution of the process protrusions 20a or process recesses 20b can make the stress distribution along the edges of the board surface more even during the molding process. The two rows of protrusions 20a or process recesses 20b are more densely distributed, which can effectively reduce the springback value along the edges of the board surface.

Claims

1. A forming process for high-strength plate beam components, characterized in that... The molding process is as follows: A. Provide flat plate beam blanks (10a1); B. Pre-forming: Stamping out the formed integral part (10), the formed integral part (10) includes a first pre-formed part (11) and a second pre-formed part (12). The cross-section of the formed integral part (10) is generally a groove shape with an external flange at the groove opening. The first preform (11) and the second preform (12) are mirror images of each other with the center of the groove width of the integral part (10) as the center of symmetry. The connection between the first preform (11) and the second preform (12) is a reserved shearing strip (30). The first preform (11) and the second preform (12) on the side of the reserved shearing strip (30) have low process protrusions (20a) or shallow process recesses (20b). C. Pressing and stamping to remove process protrusions (20a) or process depressions (20b); D. Blanking and parting, stamping and shearing off the reserved shearing strip (30).

2. The forming process for high-strength plate beams according to claim 1, characterized in that: The process protrusions (20a) or process recesses (20b) described in step B are symmetrically distributed on the bottom surface of the groove of the molded integral part (10) relative to the reserved shear band (30).

3. The forming process for high-strength plate beams according to claim 2, characterized in that: The process protrusions (20a) and process recesses (20b) on the first preform (11) and the second preform (12) are alternately distributed in the length direction of the reserved shear strip (30).

4. The forming process for high-strength plate beams according to claim 1, characterized in that... The preforming process in step B further includes: B1. Preliminary pressing and forming yields a cross-section that is flat in the center and concave on both sides. Transitional forming part (10a2); B2. Trimming and punching; B3. Lateral shaping to obtain an overall cross-section that is... A molded integral part (10) in the shape of a single piece.

5. The forming process for high-strength plate beams according to claim 1, characterized in that: In step B, the process protrusions (20a) or process recesses (20b) are densely distributed in areas with high springback values ​​and loosely distributed in areas with low springback values ​​along the edges of the first preform (11) and the second preform (12).

6. The forming process for high-strength plate beams according to claim 1, characterized in that: In step B, the diameter of the process protrusion (20a) or process recess (20b) is 10mm, and the distance between two adjacent process protrusions (20a) or process recesses (20b) distributed along the reserved shear band (30) is 30mm.

7. The forming process for high-strength plate beams according to claim 5, characterized in that: The process protrusions (20a) or process recesses (20b) are distributed in a straight line along the edges of the first preform (11) and the second preform (12). In the area where the springback value is large along the edges of the first preform (11) and the second preform (12), the process protrusions (20a) or process recesses (20b) are arranged in two rows.

8. A stamping die for the forming process of high-strength plate beams as described in claim 4, characterized in that: The initial pressing die includes a pressure plate (50) located above the plate beam blank (10a1) and a punch (40) located below the plate beam blank (10a1). The pressure plate (50) has forming blades (51) arranged on both sides along the width direction of the plate beam blank (10a1). The pressure plate (50) is driven by a nitrogen spring (52) connected to its top. The bottom of the pressure plate (50) and the top of the punch (40) are respectively provided with protrusions or recesses corresponding to process protrusions (20a) or process recesses (20b).

9. The stamping die according to claim 8, characterized in that: The stamping die for the flat stamping includes a second pressure plate (50a) located above the forming integral part (10) and a second punch (40a) located below the forming integral part (10), with the pressure surfaces of the second pressure plate (50a) and the second punch (40a) being flat.

Images