Double-layer welded structure and method of forming same

Abstract

The invention provides a double-layer welding structure and a forming method thereof, at least one laser welding seam is arranged in a fitting area formed by a first component and a second component, and a temporary operation space for laser incidence is formed between the first component and the second component; using the space to form at least one laser welding seam in the preset fitting area of the two components; and after welding, external force is applied to close the temporary operation space, the two components are attached to each other in the attaching area, and therefore a welding seam is embedded into the structure. According to the method, the limitation of the material thickness is broken through, high-speed and high-strength welding of the thick plate can be realized, the air tightness of a cavity structure can be ensured, a post-welding gap is eliminated through forced attachment, internal corrosion is prevented, and the durability and reliability of a product are improved.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, and more specifically, to a double-layer welded structure and a method for forming the same. Background Technology

[0002] In the manufacturing of metal components, joining two or more layers of sheet metal or profiles is a common process requirement, and laser lap welding is a widely used technique. Traditional laser lap welding typically uses a laser beam incident perpendicularly to the workpiece surface. The laser beam must first penetrate the upper layer of material before melting into the lower layer to form a connection. However, this method has several inherent drawbacks. First, welding efficiency and quality are severely limited by the material thickness. When the material is thick, the welding speed must be reduced to ensure sufficient penetration, which not only affects production efficiency but also increases the difficulty of process control, making it difficult to guarantee stable weld quality. Second, the characteristics of laser welding—high penetration depth and narrow weld width—mean that while pursuing penetration depth, the effective joint width is relatively limited, potentially leading to insufficient joint strength or susceptibility to welding cracks. Third, for enclosed cavity structures requiring airtightness, this penetrating welding method can compromise the structural integrity, posing a risk of leakage. Finally, when the welding position is set at the end of the contact area between the two components, after the workpiece is removed from the fixture, due to the release of welding stress, a tiny gap often forms on the other side of the contact area. This gap not only affects the assembly accuracy, but more seriously, it connects with the external environment, causing the interior of the contact area to rust in the absence of anti-corrosion protection, thus affecting the long-term service life of the product.

[0003] To address the accessibility issue of welding inside components, some existing technologies have proposed pre-forming the workpiece into a specific geometry, such as a top hat, using the permanent open spaces formed at its corners as incident channels for the laser beam, thereby forming a weld inside the component. However, the final structure created by this method inherently possesses a permanent uneven profile, failing to solve the problem of perfectly flat and fitted two components in the welding area. In many applications requiring surface flatness, such an uneven final structure is undesirable. Furthermore, this approach also fails to fundamentally address the potential for incomplete bonding due to uneven stress. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of this invention is to provide a double-layer welded structure and a method for forming the same.

[0005] According to the present invention, a double-layer welded structure includes a first component and a second component, wherein a bonding area is formed between the first component and the second component; the double-layer welded structure is provided with at least one laser weld for connecting the first component and the second component, wherein the laser weld is located inside the bonding area.

[0006] Preferably, the laser weld seam is spaced apart from the boundary of the bonding area by a distance H, wherein the distance H is greater than or equal to the larger of the material thickness of the first component and the second component.

[0007] Preferably, the first component is a plate-shaped component or a cavity component, and the second component is a plate-shaped component or a cavity component.

[0008] Preferably, a plurality of laser weld seams are provided inside the bonding area.

[0009] The present invention also provides a method for forming a double-layer welded structure, comprising the following steps: providing a first component and a second component; forming a temporary operating space for laser injection, the temporary operating space being disposed between the first component and the second component; using the temporary operating space, penetrating the first component or the second component with a laser beam to form at least one laser weld seam inside a predetermined bonding area of ​​the first component and the second component, thereby connecting the first component and the second component; after the laser weld seam is formed, applying an external force to the first component or the second component to close the temporary operating space, and causing the first component and the second component to bond together in the predetermined bonding area to form the bonding area.

[0010] Preferably, the step of forming the temporary operating space includes: tilting the first component relative to the second component by an angle θ.

[0011] Preferably, the angle θ is between 5° and 45°.

[0012] Preferably, the step of applying external force includes: applying the external force through a roller pressing device.

[0013] Preferably, the step of forming the temporary operating space includes: preforming the first component or the second component by a roll forming process.

[0014] Preferably, the first component is a plate-shaped component or a cavity component, and the second component is a plate-shaped component or a cavity component.

[0015] Preferably, the predetermined bonding area is inspected using a visual inspection device, and the operating parameters of the laser device and the rolling device are adjusted based on the inspection results.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention breaks through the thickness limitation and improves efficiency and strength. By using lateral internal welding instead of vertical penetration, the welding process is no longer directly limited by the material thickness, enabling high-speed and high-strength welding of thick plates. At the same time, by flexibly designing the weld length, it can ensure that the weld strength is not lower than the strength of the base material.

[0017] 2. This invention can ensure airtightness and structural integrity. Since the welding process does not penetrate the thickness direction of the component, the original outer surface of the component is completely preserved. Therefore, it is particularly suitable for cavity products with high requirements for airtightness, and fundamentally avoids the air leakage problem that may be caused by traditional through welding.

[0018] 3. This invention can eliminate the gaps in the joint and prevent internal corrosion. The invention adopts a unique process of "welding with an opening first, then closing and compacting". The weld is set inside the structure and external force is applied to force the surfaces of the two components to finally fit completely. This effectively avoids the small gaps caused by stress release in traditional end welding, and completely seals the weld and the joint area, preventing moisture intrusion and internal corrosion, and significantly improving the durability and reliability of the product.

[0019] 4. The present invention is flexible in design and widely applicable. The position and number of welds in the present invention can be flexibly set within the bonding area according to the strength and sealing requirements. It is suitable for various structural combinations such as plate-plate, plate-cavity, and complex profiles, providing greater freedom for product structure design. It is also easy to integrate with efficient processes such as roll forming and has good prospects for industrial application. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of conventional laser cladding technology in the prior art; Figure 2 This is a schematic diagram illustrating defects caused by end welding in existing technologies. Figure 3 A schematic diagram of the core parameters of the double-layer welded structure; Figure 4 Structural diagram when both the first and second components are plate-shaped Figure 1 ; Figures 5 to 9 This is a flowchart illustrating the method for forming a double-layer welded structure. Figure 10 Structural diagram when both the first and second components are plate-shaped Figure 2 ; Figure 11This is a schematic diagram of a double-layer welded structure where the first component is plate-shaped and the second component is a single-cavity structure. Figure 1 ; Figure 12 This is a schematic diagram of a double-layer welded structure where the first component is plate-shaped and the second component is a single-cavity structure. Figure 2 ; Figure 13 This is a schematic diagram of a double-layer welded structure where the first component is plate-shaped and the second component is a single-cavity structure. Figure 3 ; Figure 14 This is a schematic diagram of a double-layer welded structure where the first component is plate-shaped and the second component is a single-cavity structure. Figure 4 ; Figure 15 A schematic diagram of a double-layer welded structure with multiple weld locations; Figure 16 This is a schematic diagram illustrating the use of visual inspection equipment.

[0021] The diagram shows: 1. Upper plate; 2. Lower plate; 3. Weld nugget; 4. Weld width; 5. Weld depth; 6. Weld seam; 7. Gap; 8. Internal weld seam; 9. External weld seam; 10. First component; 11. Second component; Detailed Implementation The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Before describing the embodiments of the present invention in detail, the problems existing in the prior art will be briefly explained. (See also...) Figure 1 This demonstrates the traditional laser shing method in existing technologies. Whether or not... Figure 1 The semi-penetration weld shown in (a) is still... Figure 1 (b) In the full penetration welding shown, the laser beam must penetrate vertically through the upper plate 1 and melt the lower plate 2 to form the weld nugget 3. In this method, the penetration depth 5 and weld width 4 are significantly affected by the material thickness, especially when processing thick plates; to ensure penetration depth, the welding speed must be reduced. Furthermore, full penetration welding can compromise the structural integrity of the lower plate, therefore it is not suitable for applications requiring airtightness. See also... Figure 2This invention illustrates a defect arising from end welding in another prior art. A T-joint consisting of a first component 10 and a second component 11 is connected at its ends by a weld 6. After welding, due to the release of welding heat stress during cooling, a small gap 7 often forms at the root of the contact area between the two components. This gap 7 is open to the external environment, easily allowing moisture and corrosive media to penetrate, causing internal corrosion in the contact area, thus seriously affecting the durability and reliability of the product. In view of this, the present invention provides a technical solution aimed at solving the above-mentioned problems.

[0023] Example 1 This embodiment illustrates a double-layer welded structure and its formation method, which is particularly suitable for plate-to-plate connection applications, such as T-joints.

[0024] Please see Figure 3 This embodiment provides a double-layer welded structure composed of a first component 10 and a second component 11. In this embodiment, both the first component 10 and the second component 11 are plate-shaped pieces, specifically high-strength steel plates with a thickness of t=4mm. The first component 10 and the second component 11 are connected in a T-shape, forming a contact area with a predetermined contact length L. A technical feature of this embodiment is that the laser weld used to connect the first component 10 and the second component 11, i.e., the internal weld 8, is not located at the end of the contact area, but is completely located inside the contact area. Figure 4 As shown, after the first component 10 and the second component 11 are fully bonded together, an external weld 9 can be formed at the end after the internal weld is formed.

[0025] Specifically, such as Figure 3 and Figure 4 As shown, the boundary between the internal weld 8 and the bonding area, particularly the open end on the laser incident side, is separated by a specific distance H. To ensure that the weld area can be completely and reliably closed in the subsequent closing process, this distance H must meet specific conditions. As a preferred embodiment, the value of distance H is greater than or equal to the larger of the material thicknesses of the first component 10 and the second component 11. In this embodiment, since both components are 4mm thick, the distance H is set to 5mm, satisfying the condition H≥t (t=4mm). This setting ensures that after the first component 10 is flattened and closed, there is still a sufficiently wide base material area on the outside of the internal weld 8 to form a tight physical contact, thereby completely isolating the internal weld 8 from the external environment. In this embodiment, the total bonding length L is set to 20mm, and the effective connection length of the internal weld 8 is designed to be 4mm. This length is greater than or equal to 0.8 times the material thickness t (i.e., 4mm ≥ 4mm * 0.8 = 3.2mm), ensuring that the strength of the welded joint is not lower than the strength of the base material.

[0026] The following is combined with Figures 5 to 9 As shown, the method for forming the above-mentioned double-layer welded structure is described.

[0027] First, through Figures 5 to 8 In the first to 18th passes, the first component 10 and the second component 11 are formed, aligning the first component 10 and the second component 11 with an angle of inclination. For example... Figure 9 As shown, in the 19th pass, through tooling fixture positioning or pre-forming process, the end of the first component 10 to be welded is tilted at a preset angle θ relative to the mating surface of the second component 11, thereby forming a wedge-shaped temporary operating space between them for laser injection. The angle θ needs to be set in a way that balances two aspects: first, ensuring that the laser welding head and its nozzle can enter unimpeded and be aligned with the welding position at a suitable angle; second, avoiding an excessively large angle that would require excessive external force during subsequent flattening and closing or cause excessive material deformation. In this embodiment, the angle θ is set to 15°, which is within the preferred range of 5° to 45°, effectively balancing welding accessibility and forming economy.

[0028] Subsequently, as Figure 9 As shown, in the 20th pass, lateral internal welding is performed. After forming a temporary operating space, the workpiece is transported to the laser welding station. The laser welding head extends from the opening with an angle θ of 15°, and the laser beam is precisely aligned with the predetermined welding position located inside the mating area in a lateral incident manner. The distance between this position and the end of the opening is H=5mm. The laser is activated, and continuous welding is performed along the length of the workpiece to form the internal weld 8. Since the welding process is performed on the side of the component, the laser energy is mainly used to melt the contact interface between the two components without penetrating the entire material thickness, thus a higher welding speed can be used. In this embodiment, for a 4mm thick steel plate, the welding speed can reach 6m / min, which is significantly higher than that of traditional through-welding. It should be noted that a protective gas (such as argon) can be used as needed during the welding process to prevent weld oxidation and ensure welding quality.

[0029] Finally, as Figure 9 As shown, in the 21st pass, flattening and closing are performed. After welding, the workpiece is conveyed to the next station. At this station, a device that applies external force, such as a roller press, applies a vertically downward pressure to the first component 10, which is in an inclined state. Under this external force, the first component 10 undergoes plastic deformation, rotates around its root, and presses downward toward the second component 11 until the previously formed temporary operating space is completely closed. Finally, the bottom surface of the first component 10 and the top surface of the second component 11 achieve a complete and tight fit along the entire bonding length L. At this point, the internal weld 8 is completely "embedded" and sealed between the two components, forming a final stable and sealed T-shaped welded structure.

[0030] Using the structure and method of this embodiment, high-speed, high-strength welding of 4mm thick steel plates can be achieved. The final product exhibits a tight fit between the first component 10 and the second component 11 in the mating area, with no visible gaps, thus avoiding… Figure 2 The gap 7 shown is generated. Because the internal weld 8 is completely enclosed within the structure and is not directly affected by the external environment, the structure has excellent corrosion resistance and long-term structural stability, significantly improving the product's service life and reliability.

[0031] like Figure 10 As shown, this is another welded structure where both the first component 10 and the second component 11 are plate-shaped, which can also be formed by the above method.

[0032] like Figure 16 As shown, this embodiment includes an online weld seam internal monitoring system installed before the welding equipment. This high-precision visual inspection device employs advanced CCD technology (with a charge-coupled device image sensor) to efficiently identify defects such as cracks and porosity that are prone to occur during the welding process at the internal bonding positions. The system feeds back real-time data signals collected by the weld seam monitoring system to a servo motor mounted on the roller pressing device, enabling precise and flexible control of the gap or angle between the temporary space between the first and second components in the 19th pass, further improving the internal weld seam quality. Simultaneously, by utilizing welding technology database cards and controlling and adjusting welding process parameters such as welding speed, welding power, spot diameter, defocusing amount, and shielding gas, the weld seam quality is further improved, and the stability of the entire welding process is ensured.

[0033] During the 20th and 21st bonding processes, preheated protective gas is sprayed onto the fused internal weld seam, with the temperature set between 80 and 150 degrees Celsius. This prevents the high temperature from causing a low-temperature tempering effect on the material and altering its properties. At the same time, the protection of a certain temperature reduces the cooling rate after welding, thereby eliminating or reducing the stress generated during the bonding process.

[0034] Example 2 This embodiment demonstrates the application of the technical solution of this application in connecting plate-shaped parts and cavity parts, and reflects its advantages in ensuring the airtightness of the cavity structure.

[0035] Please see Figures 11 to 14 This embodiment provides a double-layer welded structure, consisting of a plate-shaped first component 10 and a closed cavity-shaped second component 11 with a rectangular cross-section. Such structures are commonly found in applications such as welded reinforcing plates for vehicle body frames or connecting brackets, where maintaining the airtightness of the cavity component is crucial for corrosion protection, dust prevention, or achieving specific functions.

[0036] Similar to Embodiment 1, the connection in this embodiment also relies on an internal weld 8 located within the mating area, which securely welds the plate-shaped first component 10 to the side wall of the second component 11. Crucially, the entire welding process does not penetrate the cavity wall of the second component 11.

[0037] The method for forming this structure follows the same core process as in Embodiment 1. First, a prefabricated plate-shaped first component 10 and a closed cavity-shaped second component 11 are provided. In the step of forming a temporary operating space, the plate-shaped first component 10 can be pre-bent or clamped with a tool in the area to be welded, tilting it at an angle θ relative to the flat sidewall of the second component 11. As an optional implementation, to provide more ample operating space for the laser head, the angle θ can be set to 30°, which is also within the preferred range of 5° to 45°.

[0038] Next, in the lateral internal welding step, the laser beam enters from the 30° temporary operating space and welds at the predetermined contact area between the sidewalls of the first component 10 and the second component 11, forming an internal weld 8. By optimizing welding parameters (such as power, speed, defocusing amount, etc.), a reliable connection with sufficient penetration depth and width is ensured between the two components, while precisely controlling the penetration depth of the laser energy to prevent it from melting through the wall thickness of the second component 11. This is fundamentally different from... Figure 1 The traditional through-welding method shown avoids compromising the integrity of the cavity.

[0039] After welding is completed, the flattening and closing step is carried out. External force is applied to the inclined first component 10 by means of rolling or stamping, so that it is flattened and tightly attached to the outer wall of the second component 11, thereby closing the temporary operating space and sealing the internal weld 8 inside.

[0040] The airtightness of the welded structural components manufactured using the method of this embodiment was tested, and the results demonstrated the beneficial effects of this solution. Specifically, the second component 11 (cavity component) was filled with compressed air at a certain pressure, and then the entire structural component was immersed in water for observation. Under the test pressure, the cavity structure remained intact, and no bubbles were observed to escape, proving that the welding method of this application can achieve high-strength external component connections without compromising the airtightness of the cavity.

[0041] like Figure 15 As shown, in other embodiments, there are also profile structures with multiple weld locations, which can also be formed into corresponding welded structures using the above method.

[0042] Example 3 This embodiment provides a double-layer welding structure and method, specifically a laser welding structure and processing method between plates and between a plate and a cavity. Instead of the traditional laser penetration welding perpendicular to the plane of the plate, it is designed as a structure parallel to one side of the plate and the other side of the plate or cavity. It is set at any position inside the two-layer bonding position and laser welding is used to ensure the stability of the welding process, improve the welding speed, and ensure more stable welding quality.

[0043] In traditional double-layer welding technology, the laser incident angle is perpendicular to the plane. It is necessary to penetrate the first layer of material first, and then penetrate the second layer of material by at least 1 / 2 thickness t, or even completely penetrate both layers. The effect is to fuse the materials together at the joint of the two layers to ensure the welding is achieved. However, the welding speed v is related to the material fusion depth t. The thicker the material t, the slower the speed v and the more difficult it is to achieve. The connection strength Rm of the two layers mainly depends on the width b of the double-layer joint. Since the laser welding has a large penetration depth / penetration width ratio, the deeper the penetration depth, the narrower the penetration width, and the lower the connection strength.

[0044] Traditional lap welding connections are susceptible to defects such as weld cracks, low weld strength, and poor airtightness due to process conditions, affecting product quality. During welding, the parts are perfectly bonded between the two layers of material within the welding mold, without gaps. However, once the parts leave the mold and lose external constraints, a certain bonding length L exists at the bonding point. If the welding point is located at the end of the bonding area, a gap 'a' will remain after the welding constraint is released on the other side. This prevents the two layers from fully bonding. Typically, when applying an anti-corrosion coating later, the coating cannot be applied to the bonding area. Even a small gap 'a' at one end will lead to rusting after prolonged contact with air. Therefore, proper welding techniques and placement are needed to ensure proper bonding between the two layers. Thus, one or more welds need to be placed inside the two layers to effectively prevent rusting caused by gaps.

[0045] This embodiment presents a novel approach to the structure and method of roll forming and welding under a double-layer material structure. The structure consists of a plate-like side and a plate-like or cavity-like side. The bonding positions can be one or multiple, and the weld seam must be embedded inside the structure. The length of the bonding position is L, and the welding position is far from the closed end of the material (the side where the laser is incident) and at a certain distance H from the outside of the double-layer material, where H ≥ material thickness t. The weld seam can be arbitrarily arranged between H and Lt, and the effective connection length of the weld seam is ≥ material thickness 0.8t.

[0046] During the welding process, since the weld is located inside the structure, it is necessary to set up the laser incident space on one or both sides. The plate on one side and the center line of the welding are at a certain angle, where the angle θ is 0 to 90 degrees, preferably >5° to 45°, so as to achieve welding. After the welding is completed, the plate material on one side is pressed against the plate or cavity plane on the other side by a roller pressing mold to achieve the embedding of the weld inside the structure.

[0047] The other end of the weld must be connected to the plate or cavity through a connecting structure. The connecting structure can be a bent arc, a bent cavity, or a double-layered, gapless fit, and continue to connect to the plate or cavity on the other side. This structure is closed at one end and open at the other end for welding.

[0048] like Figure 3 , Figure 4 , Figure 10 As shown, this is a welded structure with one side being plate-shaped and the other side also being plate-shaped. For example... Figures 11 to 14 As shown, this is a welded structure with a plate-like structure on one side and a single-cavity structure on the other. For example... Figure 15 As shown, this is a welded structure with multiple weld locations.

[0049] Traditional laser lap welding has an upper limit on thickness. Beyond a certain range, such as 3mm or more, welding becomes difficult or the welding speed is very low. The process is difficult, the welding strength is low, and the weld is prone to breakage and cracking. With the structure and method of this embodiment, there is no thickness limitation. Even thick plates can achieve efficient and stable quality welding with high welding strength and fast welding speed, which can exceed 5m / min.

[0050] Penetration welding requires the material to penetrate in the thickness direction to achieve welding. Therefore, for products with high airtightness requirements, airtightness problems such as air leakage are prone to occur. With the structure and method of this embodiment, the material does not suffer through-penetration damage in the thickness direction, ensuring the integrity of the material. At the same time, the effective connection length of the welding position can exceed the material thickness, ensuring that the welding strength is not lower than the material strength. This ensures both the integrity of the material and the airtightness of the structure, while also meeting the welding strength requirements.

[0051] Traditional spot welding involves intermittent placement, which cannot achieve continuous full welding, thus failing to meet airtightness requirements. Furthermore, spot welding has structural limitations, requiring sufficient welding space for the welding torch and restricting the placement of weld points. For structures with one cavity, welding is impossible or requires large through-holes for the welding torch, leading to structural damage and reduced strength. The structure and method of this embodiment effectively solve these problems. By designing a plate-like structure on one side and a cavity structure on the other, and applying extrusion pressure to both sides using a roller pressing die, continuous full welding can be achieved, ensuring airtightness.

[0052] The structure and method of this embodiment can realize a new approach to roll forming and welding of double-layer structural materials. The structure is plate-shaped on one side and plate-shaped or cavity-shaped on the other side. The type and thickness of the material are not limited. The weld seam can be set in multiple locations. The laser welding incident angle is set from 0 to 90 degrees. The weld seam is set within the double-layer bonding range L, preferably far from the outer end of the bonding. H > material thickness t. It can realize high-speed, high-quality, high-strength laser welding between materials. The structure is complete, the connection strength is high, the structure design is diverse, and the technical manufacturing feasibility is more friendly.

[0053] In this embodiment, the two layers of material are bonded over a larger area, and the welding positions are all within the bonding area. In addition to ensuring welding strength, the weld is mainly designed to ensure that the two layers can be completely bonded together, preventing a tiny gap from forming at the bonding position due to stress release after the mold constraint disappears.

[0054] In this embodiment, the structure and method allow for arbitrary adjustment of the welding position and quantity within the bonding process, with the ultimate goal of eliminating gaps in the double-layer bonding.

[0055] This invention provides a double-layer welded structure and its formation method, belonging to the field of metal processing technology. The invention aims to solve the problems of traditional lap welding, such as difficulty in welding thick plates, inability to guarantee airtightness, and susceptibility to internal corrosion due to stress-induced gaps after welding. The double-layer welded structure of this invention has at least one laser weld seam inside the mating area formed by the first and second components. The method of forming this structure includes: forming a temporary operating space between the first and second components for laser injection; using this space, forming at least one laser weld seam inside the predetermined mating area of ​​the two components; after welding, applying external force to close the temporary operating space, causing the two components to fit together in the mating area, thereby embedding the weld seam inside the structure. This invention overcomes the limitations of material thickness, enabling high-speed, high-strength welding of thick plates, ensuring the airtightness of the cavity structure, and eliminating post-weld gaps through forced mating, preventing internal corrosion and improving the durability and reliability of the product.

[0056] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0057] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A double-layer welded structure, characterized in that, It includes a first component and a second component, and a mating area is formed between the first component and the second component; The double-layer welded structure is provided with at least one laser weld for connecting the first component and the second component, and the laser weld is located inside the bonding area.

2. The double-layer welded structure according to claim 1, characterized in that, The laser weld seam is separated from the boundary of the bonding area by a distance H, the distance H being greater than or equal to the larger of the material thickness of the first component and the second component.

3. The double-layer welded structure according to claim 1 or 2, characterized in that, The first component is a plate-shaped component or a cavity component, and the second component is a plate-shaped component or a cavity component.

4. The double-layer welded structure according to claim 1 or 2, characterized in that, Multiple laser weld seams are provided inside the bonding area.

5. A method for forming a double-layer welded structure, characterized in that, Includes the following steps: Provide the first component and the second component; A temporary operating space for laser injection is formed, the temporary operating space being disposed between the first component and the second component; Using the temporary operating space, a laser beam is penetrated through the first component or the second component to form at least one laser weld seam inside a predetermined mating area of ​​the first component and the second component, so as to connect the first component and the second component; After the laser weld is formed, an external force is applied to the first component or the second component to close the temporary operating space and to make the first component and the second component fit together in the predetermined fitting area to form the fitting area.

6. The method for forming a double-layer welded structure according to claim 5, characterized in that, The steps to form a temporary operating space include: tilting the first component relative to the second component by an angle θ.

7. The method for forming a double-layer welded structure according to claim 6, characterized in that, The angle θ is between 5° and 45°.

8. The method for forming a double-layer welded structure according to any one of claims 5 to 7, characterized in that, The steps for applying external force include: applying external force through a roller pressing device.

9. The method for forming a double-layer welded structure according to claim 5, characterized in that, The steps for forming a temporary operating space include: preforming the first component or the second component by a roll forming process.

10. The method for forming a double-layer welded structure according to claim 5, 6, 7, or 9, characterized in that, The first component is a plate-shaped component or a cavity component, and the second component is a plate-shaped component or a cavity component.

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