Method for manufacturing fasteners for dissimilar metal welding and split fasteners

Abstract

The application provides a fastener manufacturing method for dissimilar metal welding and a split fastener thereof. The manufacturing method separately adopts different thickness of blank to independently stamp the thin-wall structure and the circular cone structure of the fastener. After stamping, the circular cone structure is installed on the center installation slot of the thin-wall structure in an interference fit mode to form the shaft part of the fastener. The split fastener realizes more flexible design and independent manufacturing effect of the thin-wall structure and the circular cone structure, reduces the manufacturing cost and improves the manufacturing precision. In addition, the strength and hardness of the circular cone structure can be improved by selecting the material and post-processing mode of the circular cone structure, the effect of the fastener shaft part in piercing the workpiece during welding is improved, and the quality of the fastener in welding dissimilar metals is improved.

Description

Technical Field

[0001] This invention belongs to the field of fastener manufacturing, specifically relating to a fastener manufacturing method for welding dissimilar metals and its composite fastener. Background Technology

[0002] With the development of lightweighting in automobiles and the rapid development and popularization of new energy vehicles, high safety and long driving range have become the focus of attention in the field. To improve vehicle safety while achieving lightweighting, thereby increasing driving range and reducing energy consumption, the use of multi-material hybrids, primarily aluminum and steel, in automobile body manufacturing has become an important approach. Therefore, there is a wide demand for dissimilar metal joining in hybrid body manufacturing. However, the significant differences in the physical and chemical properties of dissimilar metals make it difficult to obtain high-quality joints through welding technology, which limits the application of welding technology in hybrid material body manufacturing. To achieve efficient welding of dissimilar metals, CN114211104B discloses a welding method that uses an active induction technique to induce spatter in low-melting-point metals to remove low-melting-point material from the weld joint, and then uses electrode force to weld high-melting-point metals together. Regarding this welding process, to address the problem of actively induced spatter during welding, CN217316508U discloses a welding element with a receiving cavity, the cross-section of which is a "C"-shaped folded edge. CN116810111A discloses a welding element with a cap structure featuring a thin-walled cavity. These disclosed welding elements (referred to as fasteners in this invention) demonstrate good performance in welding dissimilar metals and also function to collect spattered metal. However, in the current technological context, to achieve low-cost and efficient manufacturing of fasteners, the mainstream manufacturing process for welding elements (fasteners) is cold stamping. However, the welding elements (fasteners) disclosed in CN217316508U and CN116810111A are integral structures, formed by stamping a single blank. Because the central region of the fastener is thicker than the outer region, it is difficult to achieve efficient stamping from a single blank. Especially in the thin areas, multiple stamping cycles are required to achieve the thinning effect, resulting in high manufacturing costs and low efficiency. Furthermore, the numerous stamping cycles can easily lead to cracks in the die core and fastener, and make dimensional accuracy difficult to control. Therefore, there is an urgent need in the art for a fastener manufacturing method that achieves efficient and low-cost manufacturing of fasteners, thereby ensuring the welding quality of dissimilar metals and reducing the welding cost of dissimilar metals. Summary of the Invention

[0003] The purpose of this invention is to provide a fastener manufacturing method for welding dissimilar metals and a splicing fastener thereof, thereby improving the manufacturing efficiency and reducing the manufacturing cost of fasteners, improving the weld quality of fasteners welding dissimilar metals, and reducing the manufacturing cost of weld joints.

[0004] To achieve the above objectives, a method for manufacturing fasteners for welding dissimilar metals is provided, characterized by comprising: using metal A with a thickness of less than 0.9 mm as a thin blank, repeatedly stamping the thin blank with a first forming die to form a cap-shaped thin-walled structure, wherein an annular mounting groove is formed in the central region of the thin-walled structure, and an arc-shaped curved area and a straight wall area are formed around the mounting groove; and using a rotary cutting die to cut the ends of the straight wall area to ensure that the dimensions of the thin-walled structure are compliant and the surface is flat; using metal B with a thickness of more than 2 mm as a thick blank, repeatedly stamping with a second forming die to form a frustum structure, and forming a mounting part on the side of one end of the bottom surface of the frustum structure, wherein the mounting part is interference-fitted with the mounting groove for installation.

[0005] Furthermore, during the stamping process, the thin-walled structure forces the material in the curved area to flow towards the straight wall area and both sides of the mounting groove, and the material in the central area of ​​the thin-walled structure flows towards the mounting groove, so that the minimum wall thickness of the curved area does not exceed that of the straight wall area, while the wall thickness in the area near the mounting groove is greater than the original thickness of the blank.

[0006] Preferably, the thickness of the thin blank ranges from 0.4 mm to 0.6 mm;

[0007] Optionally, metal A and metal B can be the same metal or different metals;

[0008] Preferably, metal A is made of alloys such as aluminum alloy and low-carbon steel, which have excellent ductility and low hardness, reducing the difficulty of stamping and manufacturing thin-walled structures and improving their deformation capacity during welding. The frustum structure is made of alloys such as medium-carbon steel (e.g., 45# steel), high-strength steel (e.g., duplex steel), and stainless steel, which improves the ability of the fastener shaft to pierce the workpiece to be welded and avoids excessive upsetting deformation of the fastener shaft during welding, thus reducing the mechanical locking capacity to the first metal.

[0009] Furthermore, the central region of the thin-walled structure is a hollow structure, and the mounting groove is disposed around the hollow structure.

[0010] Furthermore, it also includes post-processing of the frustum structure, including heat treatment, surface shot peening, surface nitriding, and surface carbon nitriding.

[0011] Preferably, the Vickers hardness of the thin-walled structure is less than 200 Hv, and the Vickers hardness of the frustum structure is greater than 1.2 times that of the thin-walled structure.

[0012] Preferably, the frustum structure is subjected to surface shot peening, carburizing, or carbonitriding to form a surface hardened layer, the thickness of which is less than 1 mm and the surface Vickers hardness is greater than 500 Hv.

[0013] Preferably, the fastener surface has an anti-corrosion coating, and the thickness and type of the anti-corrosion coating are different for the thin-walled structure and the frustum structure.

[0014] Furthermore, the first forming die is characterized by having four to seven first die cores, each first die core stamping the thin blank once, the first die core pressing down by no more than 0.25 mm each time, and the stamping force range being 80 to 120 tons; the second forming die is characterized by having three to five second die cores, each second die core stamping the thick blank once, the second die core pressing down by no more than 0.35 mm each time, and the stamping force range being 60 to 80 tons.

[0015] Preferably, the pressing amount of the first mold core is in the range of 0.1 to 0.18 mm each time, and the pressing amount of the second mold core is in the range of 0.12 to 0.22 mm each time.

[0016] Furthermore, the maximum wall thickness of the arc-shaped bending area is less than 0.5 mm, and the maximum thickness of the mounting groove area is less than 1.5 mm.

[0017] Furthermore, before welding, the thin-walled structure is placed in the first distributor and the frustum structure is placed in the second distributor. The first and second distributors move the thin-walled structure and the frustum structure into the assembly equipment one by one to realize the assembly and installation of the thin-walled structure and the frustum structure.

[0018] According to another aspect of the present invention, an interlocking fastener is provided, which is manufactured using the manufacturing method described above.

[0019] According to another aspect of the present invention, a method for laminating dissimilar metals is provided, wherein the first metal has a melting point of less than 750°C and the second metal has a melting point of greater than 1300°C. The method is characterized by employing the aforementioned composite fasteners for welding, wherein the end of the straight-walled region of the thin-walled structure of the fastener extends at least to the plane containing the end face of the solid shaft portion of the fastener. This ensures that when the fastener is pressed against the workpiece for welding, the end of the straight-walled region of the thin-walled structure remains in contact with the workpiece surface, thereby fully collecting the spatter metal ejected from the weld joint.

[0020] Preferably, after the fastener is welded with a dissimilar metal, the thin-walled structure carries the splashed metal and separates from the frustum structure.

[0021] The beneficial effects of this invention are:

[0022] (1) The thin-walled area on the periphery and the thick area in the center of the fastener are stamped separately. The thin-walled structure is stamped with a thin blank, and the central truncated cone structure is stamped with a thick blank. On the one hand, the difficulty of cold stamping manufacturing of the thin-walled structure is reduced, and the manufacturing efficiency and dimensional accuracy of the thin-walled structure are improved. On the other hand, it avoids the need for more stamping times to thin the periphery of the fastener when using a single thick blank for stamping, thereby reducing the wear rate of the mold and the risk of cracking in the thin-walled area.

[0023] (2) The outer thin-walled structure and the central shaft of the fastener are manufactured separately. The thin-walled structure is made of a material with excellent plasticity, which is beneficial for thinning and forming during manufacturing. In addition, it can also improve the plastic deformation capacity of the thin-walled structure during the welding process and avoid the thin-walled structure interfering with the process of the central shaft piercing the workpiece. The frustum structure can be made of a metal material with higher strength than the thin-walled structure, which not only ensures better manufacturing effect, expands the breadth of manufacturing material selection, but also improves the efficiency of the fastener shaft piercing the workpiece and the welding quality.

[0024] (3) The present invention manufactures thin-walled structure and frustum structure independently. By welding dissimilar metal materials of different thicknesses into fasteners, different sizes of frustum structures can be switched more flexibly under the premise of using the same thin-walled structure, thereby improving the flexibility of fastener use.

[0025] (4) Thin-walled structure and frustum structure are manufactured by stamping independently, which is beneficial to set a hardening layer on the surface of frustum structure, improve the strength of fastener shaft, and improve the ability of fastener shaft to pierce the workpiece to be welded.

[0026] (5) The fasteners formed by combining the thin-walled structure and the frustum structure can remove the thin-walled structure and the spatter metal contained therein after welding, thereby reducing the flatness of the weld point.

[0027] (6) It is convenient to set different anti-corrosion coatings for thin-walled structures and frustum structures. Under the premise of ensuring that the joint has the best anti-corrosion effect, more flexible coating design can be achieved, thereby reducing the manufacturing cost of the coating. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the fastener manufacturing method disclosed herein;

[0029] Figure 2 This is a schematic diagram of the thin-walled structure stamping process disclosed herein;

[0030] Figure 3 This is a schematic diagram of material flow during the stamping of the thin-walled structure disclosed herein.

[0031] Figure 4 This is a schematic diagram of the stamping process for the frustum structure disclosed herein.

[0032] Figure 5 This is a schematic diagram of the material flow during the stamping of the frustum structure disclosed herein.

[0033] Figure 6 This is a schematic diagram of the fastener assembly in one embodiment of the present disclosure.

[0034] Figure 7 This is a cross-sectional schematic diagram of a fastener in one embodiment of the present disclosure;

[0035] Figure 8 This is a cross-sectional schematic diagram of a fastener in another embodiment of the present disclosure;

[0036] Figure 9 This is a cross-sectional schematic diagram of a fastener in yet another embodiment of the present disclosure;

[0037] Figure 10 This is a schematic diagram of fasteners used for different welding combinations in another embodiment of the present disclosure;

[0038] Figure 11 A schematic diagram showing the relationship between welding current, electrode pressure and time during dissimilar metal resistance spot welding of the assembled fasteners of this disclosure.

[0039] Figure 12 This is a schematic diagram illustrating the welding process of the assembled fasteners disclosed herein.

[0040] Figure 13 This is a schematic diagram showing the separation of the thin-walled structure and the weld point after welding of the assembled fasteners disclosed in this invention.

[0041] Figure 14 The splicing fastener in Embodiment 1 of this disclosure;

[0042] Figure 15 Metallographic profile of the joint section of dissimilar metals welded in the assembled fasteners of Embodiment 1 of this disclosure. Detailed Implementation

[0043] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] like Figure 1 The diagram illustrates a method for manufacturing fasteners for dissimilar metal welding. Two stamping presses are used to manufacture a thin-walled structure and a frustum structure of the fastener, respectively. A first forming die 30 is mounted on a first stamping press. A metal A with a thickness less than 0.9 mm is fed into the first forming die 30 as a thin blank 10. Five first die cores 31 on the first forming die are used to stamp the thin blank 10 to form a cap-shaped thin-walled structure 103. Then, a rotary cutting die 50 is used to cut the end 103D of the straight wall region Z2 on the thin-walled structure (e.g., ...). Figure 7This ensures that the thin-walled structure has compliant dimensions and a smooth surface. Subsequently, the thin-walled structure 103 is placed in the first distributor 70, so that the thin-walled structure 103 can be transported in an orderly manner to the fastener assembly equipment 90.

[0045] Figure 2 The diagram illustrates the stamping process of the first forming die 30. Die core 31A performs blanking and a first deep drawing on the blank; die core 31B performs a second deep drawing to form a curved cap shape; die core 31C performs a third deep drawing and bulges the area near the mounting groove; die core 31D performs a fourth deep drawing and bulges the area near the mounting groove; and die core 31E punches a hole in the center area of ​​the blank and performs final dimensional control. Finally, the end of the straight-walled section of the blank is trimmed by a rotary cutting die 50 to form a thin-walled structure 103.

[0046] Figure 3 The diagram illustrates the control of material flow during the stamping process of a thin-walled structure. When the upper die core 31' and lower die core 31" press against the blank, they force the curved bending area Z3 to bend and deform. Simultaneously, the material in this area flows towards the straight wall areas Z4 and the mounting groove area Z2 on both sides, while the material in the central area Z1 of the blank flows towards the mounting groove area Z2. This results in a reduction in the wall thickness of the curved area Z2, an increase in the wall thickness of the area near the mounting groove Z2, and a wall thickness greater than the original thickness of the blank. The wall thickness of the straight wall area Z4 is also slightly increased.

[0047] like Figure 1 As shown, the second forming die 40 is mounted on the second stamping press. Four second die cores 41 are provided on the second forming die. Metal B with a thickness greater than 2 mm is continuously stamped and formed as a thick blank 20 to obtain a frustum structure 101 with a mounting portion on one side of its bottom surface. The frustum structure 101 is placed in a heating furnace 60 for heat treatment. After heat treatment, the frustum structure 101 is placed in the second feeder 80 and continuously conveyed to the fastener assembly equipment 90.

[0048] Figure 4 The diagram illustrates the stamping process of the second forming die 40 for a frustum structure. Die core 41A performs blanking and initial shaping of the blank; die core 41B performs secondary shaping; die core 41C performs tertiary shaping; and die core 41D performs bulging shaping to finally obtain the circular structure 101. During the shaping of the thick blank by the second die core, the material flow direction is controlled as follows... Figure 5As shown in A1, the die core presses against the inclined sidewall of the frustum, causing the sidewall material to flow upward and downward simultaneously. The downward-flowing material expands to form the mounting portion 102, while the upward-flowing material protrudes from the end face to form a raised structure 101'. Therefore, the die cores 41A to 41C have corresponding grooves 101" to accommodate the raised material 101'. The final die core 41D eliminates the groove 101" and instead has an annular groove 102" on the sidewall. After the die core performs the final bulging and stamping on the blank, the raised material 101' is flattened, forcing the material to flow downward and simultaneously forming a second raised structure 102' in the annular groove 102". The second raised structure 102' is used for limiting and engaging when the frustum structure 101 and the thin-walled structure 103 are installed.

[0049] The fastener assembly equipment 90 assembles the thin-walled structure 103 and the frustum structure 101 to form an assembled fastener 100. During fastener assembly, the frustum structure 101 is placed from one side into the hollow structure on the thin-walled structure 103 (e.g., ...). Figure 6 (B1), and then a certain preload is applied to make the frustum structure 101 fully engage with the thin-walled structure 103 (e.g., ...). Figure 6 (B2), so that the mounting part 102 of the frustum structure and the mounting groove 104 of the thin-walled structure 103 are completely locked together by interference fit (e.g., Figure 7 Of course, to improve the assembly strength of the two parts, in some preferred embodiments, interlocking annular structures are provided on their mating surfaces, such as... Figure 7 As shown.

[0050] Another preferred embodiment of the present invention provides a splicing fastener such as Figure 8 As shown, the thin-walled structure 103 is generally shaped like a "pot lid". The mounting groove 104' in the central region of the thin-walled structure 103 is a closed structure. The end of the frustum structure 101 engages with the mounting groove, as shown. Figure 8 As shown in C1. In some preferred embodiments, the frustum structure 101 and the thin-walled structure 103 are further reinforced by welding, such as... Figure 8 As shown in C2, for example, resistance spot welding is used to form a weld nugget 106 between the frustum structure and the thin-walled structure to enhance the connection between them.

[0051] In another preferred embodiment of the present invention, the fastener provided is as follows: Figure 9 As shown, a concave mounting groove 104 is provided in the central area of ​​the thin-walled structure 103, and the frustum structure 101 is fitted into the concave mounting groove. The side wall of the frustum structure is securely engaged with the thin-walled structure by providing a mounting part 102.

[0052] For the case where the mounting groove in the central area of ​​the thin-walled structure 103 is a closed structure, such as Figure 8 and Figure 9As shown, the frustum structure 101 and the thin-walled structure 103 are made of the same alloy, which avoids the problem of dissimilar metal welding caused during the welding process of the fastener shaft.

[0053] Since the fastener composed of the thin-walled structure 103 and the frustum structure 101 is assembled, when facing dissimilar metal combinations of different thicknesses to be welded, the same thin-walled structure can be used, and the welding effect can be achieved by changing the frustum structure of different sizes, thereby improving the flexibility of fastener use and reducing the manufacturing cost of fasteners. Figure 10 As shown in D1, when welding a first metal 200 and a second metal 300 with a thickness of T1, a fastener with a frustum structure and a total height of H1 is used for welding. When the thickness of the first metal 200 to be welded decreases to T2, the fastener can be replaced with a frustum structure with a total height of H2, as shown in Figure D1. Figure 10 As shown in D2.

[0054] According to one aspect of the present invention, a method for laminating dissimilar metals is provided, wherein dissimilar metals with a first metal melting point less than 750°C and a second metal melting point greater than 1300°C are welded. During the welding process, a composite fastener composed of a thin-walled structure 103 and a frustum structure 101 is used. The end 103D of the straight-walled region on the outer periphery of the thin-walled structure extends at least to the plane containing the end face 105 of the solid shaft portion of the fastener (e.g., ...). Figure 7 This ensures that when the fastener is pressed against the workpiece during welding, the end of the straight-walled area of ​​the thin-walled structure remains in contact with the workpiece surface, thus fully collecting any spatter metal ejected from the weld joint. For example... Figure 11 The preferred welding process is shown below. The welding process is as follows: Figure 12As shown. Specifically, it includes a preheating stage (t1~t2), a fastener piercing stage (t3~t4), and a connection stage (t5~t6). In the preheating stage, a current intensity of 3~6 kA is preferably input and maintained for 80~200 ms to improve the contact state of each contact surface within the solder joint, and to form a closed annular cavity between the surfaces of the frustum structure 101, the thin-walled structure 103, and the first metal 200, preparing for the collection of spattered metal to be discharged during the next fastener piercing stage. In the fastener piercing stage, a short-duration high current is input, for example, three pulse currents, each pulse having a current intensity of 17 kA and a duration of 48 ms. A short burst of high current rapidly heats the solder joint. The low-melting-point first metal 200 within the solder joint melts rapidly under the instantaneous surge of resistance heat, forming a large molten zone 201. Under the pressure of the electrode force and the expansion force of the molten zone 201 itself, the molten first metal forms a spatter 202 that is ejected at high speed from the solder joint and enters the closed annular cavity formed by the fastener. As the molten first metal is discharged from the solder joint, the fastener pierces the first metal 200 at high speed and forms a contact surface 301 with the second metal 300, creating conditions for subsequent connection. During the connection stage, a moderate current, such as 12 kA, is input to the solder joint and maintained for 270 ms, allowing the contact surface 301 to fully melt and form a molten nugget 302, achieving a firm weld between the fastener and the second metal. The first metal, on the one hand, engages the joint through a mechanical locking effect, and on the other hand, forms a metallurgical connection with the fastener in the molten zone 201 surrounding the fastener shaft, enhancing the connection strength between the first metal, the fastener, and the second metal.

[0055] like Figure 13 The welding process of yet another embodiment is illustrated. A ring-shaped gripping mechanism 500 is provided around the upper welding electrode 400. Before welding, the ring-shaped gripping mechanism grips and holds the fastener below the upper welding electrode 400, and then, driven by the welding machine, moves it to the welding position of the first metal 200 and second metal 300 stacked structure. Figure 13 As shown in E1. The upper and lower welding electrodes apply pressure to the weld joint and input welding current, causing spatter metal 202 to be discharged into the receiving cavity formed by the fastener thin-walled structure 103. The fastener frustum structure 101 pierces the first metal and forms a weld nugget 302 with the second metal, as shown. Figure 13 As shown in E2. After welding is completed, the annular gripping mechanism 500 applies clamping and pulling forces to the thin-walled structure 103, achieving the effect of separating the thin-walled structure 103 carrying the spatter metal 202 from the weld point, thereby improving the flatness of the weld point, as shown in E2. Figure 13 As shown in E3. In this embodiment, the thin-walled structure of the assembled fastener is preferably made of aluminum alloy, and the central area of ​​the thin-walled structure is hollow, which is beneficial for the separation of the thin-walled structure from the weld point after welding.

[0056] Example 1:

[0057] In this embodiment, a modular fastener is used to weld dissimilar metals. For example... Figure 14 This image shows the assembled effect of the frustum structure 101 and thin-walled structure 103 of the modular fastener, where they are tightly locked together. During welding, the first metal 200 is made of 2.5 mm thick 6-series aluminum alloy, and the second metal 300 is made of 1.5 mm thick aluminum-silicon coated hot-formed steel with a strength of 1500 MPa. There are no pre-drilled process holes at the welding location before welding. The electrode pressure is maintained at 5.5 kN during welding. The preferred welding process is... Figure 11 The multi-stage welding process is shown. In the preheating stage, the effective value and duration of current I1 are set to 3 kA and 100 ms, respectively. In the fastener piercing stage, current I2 is set with three current pulses, each with an effective value of 16 kA and a duration of 50 ms, and a 25 ms cooling time interval between each pulse. In the joining stage, the effective value and duration of current I3 are set to 12 kA and 200 ms, respectively. The cross-sectional morphology of the welded joint is shown below. Figure 15 As shown, after welding, the frustum structure 101 successfully pierces the first metal 200 and forms a common weld nugget 302 with the second metal workpiece 300, achieving a strong welding effect. The molten first metal discharged from the weld point is completely contained by the cavity formed by the thin-walled structure 103.

[0058] It should be understood that the above embodiments are only intended to illustrate the technical concept of the present invention to facilitate understanding by those skilled in the art, and are not intended to limit the scope of protection of the present invention. Within the scope of the claims of the present invention, any improvements and equivalent substitutions to the parts, structures, or method steps involved in the above embodiments, especially combinations of different embodiments without causing structural or principle conflicts, fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing fasteners for welding dissimilar metals, characterized in that, include: Using metal A with a thickness of less than 0.9 mm as a thin blank, the thin blank is stamped multiple times using a first forming die to form a cap-shaped thin-walled structure. An annular mounting groove is formed in the central area of ​​the thin-walled structure, and an arc-shaped bending area and a straight wall area are formed around the mounting groove. The ends of the straight wall area are cut using a rotary cutting die to make the dimensions of the thin-walled structure compliant and the surface flat. Metal B with a thickness greater than 2 mm is used as a thick blank. A frustum structure is formed by multiple stampings using a second forming die. A mounting part is formed on the side of one end of the bottom surface of the frustum structure. The mounting part and the mounting groove are installed with an interference fit. During the stamping process, the thin-walled structure forces the material in the arc-shaped bending area to flow towards the straight wall area and both sides of the mounting groove, while the material in the central area of ​​the thin-walled structure flows towards the mounting groove, so that the minimum wall thickness of the bending area does not exceed that of the straight wall area, and the wall thickness of the area near the mounting groove is greater than the original thickness of the blank. The central region of the thin-walled structure is a hollow structure, and the mounting groove is located around the hollow structure.

2. The fastener manufacturing method for dissimilar metal welding according to claim 1, characterized in that, It also includes post-processing of the frustum structure, including heat treatment, surface shot peening, surface nitriding, and surface carbon nitriding.

3. The fastener manufacturing method for dissimilar metal welding according to claim 1, characterized in that, The first forming die has four to seven first die cores, each first die core stamping the thin blank once, the first die core pressing down by no more than 0.25 mm each time, and the stamping force ranges from 80 to 120 tons; the second forming die has three to five second die cores, each second die core stamping the thick blank once, the second die core pressing down by no more than 0.35 mm each time, and the stamping force ranges from 60 to 80 tons.

4. The fastener manufacturing method for dissimilar metal welding according to claim 1, characterized in that, The maximum wall thickness of the arc-shaped bending area is less than 0.5 mm, and the maximum thickness of the mounting groove area is less than 1.5 mm.

5. The method for manufacturing fasteners for welding dissimilar metals according to any one of claims 1-4, characterized in that, Before welding, the thin-walled structure is placed in the first distributor and the frustum structure is placed in the second distributor. The first and second distributors move the thin-walled structure and the frustum structure into the assembly equipment one by one to realize the assembly and installation of the thin-walled structure and the frustum structure.

6. An interlocking fastener, manufactured using any one of the manufacturing methods described in claims 1-5.

7. A method for laminating dissimilar metals, wherein the first metal has a melting point less than 750°C and the second metal has a melting point greater than 1300°C, characterized in that, When welding is performed using the composite fastener as described in claim 6, the end of the straight wall region on the outer periphery of the thin-walled structure of the composite fastener extends at least to the plane where the end face of the solid shaft portion of the fastener is located, ensuring that when the fastener is pressed against the workpiece for welding, the end of the straight wall region on the outer periphery of the thin-walled structure can always be in contact with the workpiece surface, thereby achieving full collection of the spatter metal discharged from the weld point.

Images