A hot stamping sheet forming process

Abstract

The application relates to a hot stamping sheet forming process and belongs to the metal forming field, which comprises the following steps: according to the strength requirement of a vehicle body sheet, a metal wire type of a required metal mesh sheet is selected; a weaving process and a weaving density of the metal mesh sheet are determined; the metal mesh sheet is produced in a small batch by using a weaving device; a metal mesh sheet profile required for forming is cut; the metal mesh sheet is heated to a set temperature and kept for a set time; after the metal mesh sheet is placed into a mold, the mold is closed and stamping forming is performed; the quality of a product generated after stamping forming of the metal mesh sheet is detected; if the quality is qualified, the metal mesh sheet is mass-produced for stamping forming, so that qualified products are mass-produced; if the quality is unqualified, the metal mesh sheet manufacturing process and the metal wire material are adjusted, and the above part of the operation is repeated until the products are qualified, and the qualified products are cyclically mass-produced. The application has the effect of reducing the damage of a double-layer material to a mold after stamping.

Description

Technical Field

[0001] This application relates to the field of metal forming, and in particular to a hot stamping sheet metal forming process. Background Technology

[0002] With the continuous advancement of the automotive industry, consumers have increasingly higher demands for vehicle safety, comfort, and exterior design. This has led to a growing variety of automotive body parts with increasingly complex and diverse shapes. As a crucial component of the vehicle body, the quality of the manufacturing process for body-in-white assemblies directly affects the overall quality and performance of the car. Currently, the vast majority of body-in-white assemblies are produced by stamping metal sheets of varying thicknesses using rolling processes. This process, to a certain extent, meets the needs of automotive manufacturing and drives the development of the automotive industry.

[0003] In traditional automotive body part stamping production, the manufacturing of body-in-white assembly parts typically employs metal sheets produced through rolling processes. Specifically, rolled metal sheets of varying thicknesses are placed in a stamping die, and pressure is applied using a press, causing the sheet to undergo plastic deformation under the die's action, thus obtaining the desired part shape. This method has long been a widely used and conventional approach in the automotive manufacturing industry, possessing a certain degree of maturity and stability. Furthermore, rolled steel sheets can, to a certain extent, meet the production needs of most simple-shaped body parts with relatively low strength requirements.

[0004] In the traditional mass stamping production of steel plates, if the product is not successfully removed from the mold and remains inside, the mold will press against a double layer of material as production continues. Once this happens, it can damage the die surface steel block, or even cause the casting mold frame to crack and deform, or even scrap the mold, resulting in wasted time and production interruptions. Summary of the Invention

[0005] To reduce the damage to the mold after stamping double-layer material, this application provides a hot stamping sheet metal forming process.

[0006] This application provides a hot stamping sheet metal forming process, which adopts the following technical solution:

[0007] A hot stamping sheet metal forming process includes the following steps: S1, selecting the type of metal wire for the required metal mesh sheet based on the strength requirements of the body panel; S2, determining the weaving process of the metal mesh sheet; S3, producing metal mesh sheets in small batches using weaving equipment; S4, cutting out the outline of the metal mesh sheet required for forming; S5, heating the metal mesh sheet to a set temperature and holding it at that temperature for a set time; S6, placing the metal mesh sheet into a mold and then stamping it; S7, inspecting the quality of the product generated after stamping the metal mesh sheet. If the quality is qualified, mass-producing metal mesh sheets for stamping, thereby mass-producing qualified products; if the quality is unqualified, adjusting the metal mesh sheet manufacturing process and the metal wire material, repeating operations S3-S6 until the product is qualified, and cyclically mass-producing qualified products.

[0008] By adopting the above technical solution, using metal mesh as the raw material for hot stamping sheet metal parts reduces forming defects such as cracking in complex-shaped products during hot forming stamping production, thus improving product quality. Simultaneously, the inherent gaps in the metal mesh itself reduce damage to the mold caused by double material pressing due to automation errors during mass production, protecting the mold and hot forming press equipment. Furthermore, by adjusting parameters such as the type of metal wire and the weaving process, metal mesh with different properties can be obtained, thereby producing various parts that meet strength requirements and achieving customized product strength functionality.

[0009] Optionally, the weaving density of the metal mesh can be adjusted according to product requirements.

[0010] By adopting the above technical solution, the weaving density can be achieved by adjusting the weaving spacing of the metal wires. When a double-layer metal mesh plate is pressed, the appropriate weaving density can disperse the stress of the double-layer plate thickness when the mold presses to the bottom through the density of the metal mesh, so that the excess material is pressed into the mesh position of the metal mesh, avoiding damage to the mold due to the mold pressing double material.

[0011] Optionally, the weaving process of the metal mesh plate in S2 includes at least flexible mesh, twisted mesh, and square hole mesh.

[0012] By adopting the above technical solutions, a variety of metal mesh weaving processes are available for selection, which can further adjust the weaving density and physical properties of the metal mesh to better meet the strength requirements of different body panels and improve the molding quality and strength customization flexibility of the products.

[0013] Optionally, the set temperature in S5 is higher than 930°C, and the heat preservation set time is 290-310 seconds.

[0014] By adopting the above technical solution, in the hot stamping sheet metal forming process, heating the metal mesh plate to above 930℃ and holding it at that temperature for 290-310 seconds can austenitize the metal mesh plate material's metallographic structure. After the stamping mold is closed to the bottom and the forming is completed and cooled, it transforms into a martensitic state, which improves the tensile strength of the product, reduces forming defects such as cracking in complex-shaped products in hot stamping production, and improves product quality.

[0015] Optionally, the stamping equipment in S6 is a press with a capacity of not less than 1000T.

[0016] By adopting the above technical solution and using a press with a capacity of not less than 1000T for stamping, the forming process of the metal mesh can be better coordinated, ensuring the stability and reliability of the metal mesh stamping process and helping to produce products that meet quality requirements.

[0017] Optionally, during the stamping process in S6, the mesh structure of the metal mesh plate allows the metal wires in the ultra-thick area to undergo radial displacement.

[0018] By adopting the above technical solution, the metal wire in the ultra-thick area is radially displaced during the stamping process, which can compensate for the damage to the mold after stamping the double-layer material, avoid damage to the mold due to the mold pressing the double material, reduce the time cost of mold repair and the impact on the production process, and improve production efficiency.

[0019] Optionally, the tensile strength of the qualified product in S7 is greater than 1300 MPa.

[0020] By adopting the above technical solutions, it is ensured that qualified products produced by the hot stamping sheet metal forming process have high tensile strength, meet the strength requirements of automotive body panels, and improve product quality and reliability.

[0021] Optionally, the product generated after the metal mesh plate is stamped in step S7 is brought into the molding software to simulate the molding result. After molding, the product thinning does not exceed -15%, the formability is good, and it is judged to be qualified.

[0022] By adopting the above technical solution, it is possible to accurately determine whether the products after metal mesh stamping are qualified, ensure that the products put into mass production have good formability, avoid forming defects, and improve the overall quality of the products.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. By using metal mesh as the raw material for hot stamping sheet metal parts, the forming defects such as cracking of complex-shaped products in hot forming stamping production are reduced, the product quality is improved, and the products meet the strength requirements of vehicles.

[0025] 2. Select the type of metal wire, weaving process and weaving density according to the strength requirements of the body panels to produce metal mesh panels of different strengths to meet the strength requirements of different models and different parts of the body;

[0026] 3. When double-layer metal mesh is pressed, the mesh openings of the metal mesh can disperse the stress of the double-layer plate thickness, preventing damage to the mold due to the pressing of double materials and improving production efficiency. Attached Figure Description

[0027] Figure 1 This is a process flow diagram of a hot stamping sheet metal forming process.

[0028] Figure 2 This is a schematic diagram of the structure of a flexible network.

[0029] Figure 3 This is a structural diagram of twisted wire mesh.

[0030] Figure 4 This is a schematic diagram of the structure of a square hole mesh.

[0031] Figure 5 This is a schematic diagram of the stamping device.

[0032] Figure 6 This is a picture showing the test results after ordinary steel plate is stamped and formed.

[0033] Figure 7 This is a picture of the test results after the metal mesh is stamped.

[0034] Explanation of reference numerals in the attached diagram: 1. Upper slide block of the press; 2. Lower bed of the press; 3. Upper die; 4. Lower die. Detailed Implementation

[0035] The present application will be further described in detail below with reference to all the accompanying drawings.

[0036] This application discloses a hot stamping sheet metal forming process.

[0037] Reference Figure 1 A hot stamping sheet metal forming process includes steps such as selecting the type of metal wire according to the strength requirements of the body panel, determining the weaving process and density, small-batch weaving production, cutting the outline, heating and heat preservation, stamping, and quality inspection and subsequent production. Through the reasonable arrangement and operation of these steps, the forming defects of complex shaped products can be effectively solved, the product strength can be customized, and the mold and hot forming press equipment can be protected.

[0038] Specifically, in the step of evaluating the strength requirements of the body panels and selecting the appropriate type of wire for the metal mesh, stainless steel wire, aluminum alloy wire, etc., can be used. Stainless steel wire has high strength and corrosion resistance, making it suitable for body panels with high strength and corrosion resistance requirements; aluminum alloy wire, on the other hand, is lightweight and has good formability, making it suitable for body parts with lightweight requirements. Different metal wires have different physicochemical properties and trace element content ratios. By selecting suitable metal wires, the initial physical properties of the metal woven mesh can be altered, and its forming limits optimized to meet the different strength requirements of different vehicle models and different parts of the body.

[0039] Reference Figure 2 , Figure 3 and Figure 4 When determining the weaving process and density of the metal mesh, the weaving process should include at least three types: flexible mesh, twisted mesh, and square-hole mesh. Flexible mesh is woven from intersecting metal wires using a special connection method. Its mesh size can be adjusted as needed, offering greater flexibility and adaptability to different shapes and sizes of car body panels. For example, flexible mesh can better conform to the shape of irregularly shaped car body panels. Twisted mesh is woven by twisting metal wires together, providing strong stability and resistance to deformation. It better maintains its shape during stamping and is suitable for car body panels requiring high shape precision. Square-hole mesh is woven from metal wires in a regular grid pattern. Its regular mesh size facilitates precise control of the metal mesh's strength and forming performance, making it ideal for car body panels requiring precise strength and forming effect control. The weaving density can be adjusted by changing the spacing between the metal wires. When pressing double-layer metal mesh, a suitable weaving density can distribute the stress of the double-layer plate thickness under the die through the density of the metal mesh, allowing excess material to be pressed into the mesh openings and preventing damage to the die due to pressing double material. By changing parameters such as the metal wire material and weaving density of the woven metal mesh, raw materials with different properties can be obtained. Through the stamping process, products with corresponding strengths can be obtained, achieving the effect of product customization.

[0040] When producing metal mesh sheets in small batches using weaving equipment, the equipment can be an automated weaving machine capable of precisely weaving the metal mesh sheets according to a set weaving process and density. During the weaving process, it is essential to ensure that the metal wires are neatly arranged and tightly woven to guarantee the quality of the metal mesh sheets.

[0041] When cutting out the outline of the metal mesh required for forming, equipment such as a laser cutter can be used. Laser cutters have the advantages of high cutting precision and high speed, and can accurately cut out the outline of the metal mesh according to the design requirements, preparing it for subsequent stamping.

[0042] Before stamping and forming, the metal mesh plate is heated to above 930°C by a heating device to make the metallographic structure of the material austenitize, and insulated for 290 - 310 seconds to fully austenitize the material. The heating device can be a high-temperature heating furnace. During the heating process, the temperature and time should be strictly controlled to ensure that the performance of the metal mesh plate reaches the best state.

[0043] Refer to Figure 5 , after the metal mesh plate is placed in the mold through a conveying equipment device such as a manipulator and then the mold is closed for stamping and forming, the stamping and forming equipment uses a press with a specification not less than 1000T. Each component of the entire upper die 3 is fixed to each other, and the entire upper die 3 is fixed on the upper slider 1 of a press with a specification not less than 1000T. During production, the upper die 3 makes up-and-down stamping motions along with the upper slider 1 of the press; the entire lower die 4 is integrally fixed on the lower workbench of a press with a specification not less than 1000T. During the stamping process, the mesh hole structure of the metal mesh plate allows the metal wires in the ultra-thick area to generate radial displacement, which enables the metal mesh plate to better adapt to complex shapes during the stamping process and eliminates the problem of necking and cracking in the forming of complex products.

[0044] When detecting the quality of the product generated after the metal mesh plate is stamped and formed, the product generated after the metal mesh plate is stamped and formed is brought into the forming software to simulate the forming result. After forming, the thinning of the product does not exceed -15%, and the formability is good, so it is judged as qualified. The tensile strength of the qualified product is greater than 1300MPa. If the quality is qualified, mass production of the metal mesh plate is carried out for stamping and forming, so as to mass-produce qualified products; if the quality is unqualified, adjust the manufacturing process of the metal mesh plate and the material of the metal wire, and repeat the operations of small-batch weaving production, cutting the contour, heating and insulation, and stamping and forming until the product is qualified, and then carry out mass production in a cycle.

[0045] In this application, a comparative test is carried out on the products after stamping and forming of ordinary steel plates and metal mesh plates. The specific process and results are as follows:

[0046] Experiment 1, using an ordinary steel plate for stamping and forming, bringing it into the forming software to simulate the forming result, refer to Figure 6 It can be seen that there is a problem that the local thinning of the product after forming exceeds -15%, and it is judged that there are forming defects. In the actual production process, the corresponding position of the product will crack, and there are forming defects. And by improving and optimizing the forming process, this regional thinning of the product cannot be completely eliminated. The products of the conventional forming and production process cannot meet the customer requirements.

[0047] Experiment 2, using a metal woven mesh plate for stamping and forming, bringing it into the forming software to simulate the forming result, refer to Figure 7 It can be seen that the thinning of the product after forming does not exceed -15%, and the formability is good. It is judged that there are no forming defects, and the mold development and production and subsequent mass stamping production can be started.

[0048] The implementation principle of the hot stamping sheet metal forming process in this application embodiment is as follows: This hot stamping sheet metal forming process, by rationally selecting the type of metal wire, weaving process and density, and utilizing the easy forming characteristics of metal woven mesh, is suitable for some complex-shaped automotive sheet parts with deep forming depth and small stamping angles. When ordinary steel sheets cannot form qualified parts, metal mesh is used for stamping to achieve the purpose of producing qualified parts. This reduces forming defects such as cracking in complex-shaped products in hot stamping production and improves product quality. At the same time, by adjusting the materials of different metal wires and the metal weaving process, metal mesh with different strengths can be obtained, realizing the customization function of product strength. The metal mesh itself has gaps, which can greatly reduce the damage to the mold caused by double material pressing due to automation errors during batch stamping production, protecting the mold and hot forming press equipment, improving production efficiency, and has good practicality and innovation. It is an important improvement to the existing stamping process.

[0049] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A hot stamping sheet metal forming process, characterized in that, The process includes the following steps: S1, assess the strength requirements of the vehicle body panels and select the type of metal wire for the required metal mesh; S2, determine the weaving process for the metal mesh; S3, use weaving equipment to produce metal mesh in small batches; S4, cut out the outline of the metal mesh required for forming; S5, heat the metal mesh to a set temperature and hold it at that temperature for a set time; S6, place the metal mesh into a mold and press it into shape, filling the mesh openings with material through pressing; S7, inspect the quality of the product after the metal mesh is pressed. If the quality is qualified, mass-produce metal mesh for pressing to produce qualified products. If the quality is unqualified, adjust the metal mesh manufacturing process and the metal wire material, and repeat steps S3-S6 until the product is qualified, and then cyclically mass-produce qualified products.

2. The hot stamping sheet metal forming process according to claim 1, characterized in that: The weaving density of the metal mesh can be adjusted according to product requirements.

3. The hot stamping sheet metal forming process according to claim 1, characterized in that: The weaving process of the metal mesh plate in S2 includes at least flexible mesh, twisted mesh, and square hole mesh.

4. The hot stamping sheet metal forming process according to claim 1, characterized in that: The set temperature in S5 is higher than 930℃, and the heat preservation set time is 290-310 seconds.

5. The hot stamping sheet metal forming process according to claim 1, characterized in that: The stamping equipment in S6 uses a press with a capacity of not less than 1000T.

6. The hot stamping sheet metal forming process according to claim 1, characterized in that: During the stamping process in S6, the mesh structure of the metal mesh plate allows the metal wires in the ultra-thick area to undergo radial displacement.

7. The hot stamping sheet metal forming process according to claim 1, characterized in that: The tensile strength of the qualified product in S7 is greater than 1300 MPa.

8. The hot stamping sheet metal forming process according to claim 1, characterized in that: The product generated after the metal mesh plate in S7 is stamped and formed is brought into the forming software to simulate the forming result. The product thinning after forming does not exceed -15%, the formability is good, and it is judged to be qualified.

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