Composite laser welding process and device for copper and stainless steel and application of composite laser welding process and device

Abstract

The invention relates to a copper and stainless steel composite laser welding process and device and application of the copper and stainless steel composite laser welding process and device. The copper and stainless steel composite laser welding process comprises the steps that after the end faces of a to-be-welded copper part and a to-be-welded stainless steel part are attached and assembled to form an abutted seam, a red-blue composite welding head forms a red-blue composite laser beam through an infrared laser beam and a blue laser beam; firstly, red and blue composite laser beams are used for carrying out pre-laser welding on one or more positions of an abutted seam path, the pre-laser welding comprises spot welding and / or segmented welding, and then the red and blue composite laser beams are used for carrying out laser welding along the abutted seam path to form a welding seam. During pre-laser welding and laser welding, a light spot formed by an infrared laser beam is controlled to swing, the swing center is located on an abutted seam path, and the center of a blue light spot of a blue light laser beam is controlled to deviate to one side, outside the abutted seam path, of the copper part; filling materials such as welding wires and welding rods are not needed, the welding efficiency and quality of copper pieces and stainless steel pieces with the thickness smaller than or equal to 3 mm can be effectively improved, the production cost is remarkably reduced, and a technical path is provided for large-scale mass production of copper and stainless steel vapor chambers and the like.

Description

Technical Field

[0001] This invention belongs to the field of laser welding technology, specifically relating to a composite laser welding process and apparatus for copper and stainless steel, and its application in the production of copper and stainless steel heat exchange plates. Background Technology

[0002] Copper possesses advantages such as high thermal conductivity, good ductility, and ease of processing, making it suitable for use as a heat-conducting and heat-dissipating component. Stainless steel, on the other hand, boasts advantages such as strong thermal barrier properties, high mechanical strength, and corrosion resistance, making it suitable for structural load-bearing and protection. Connecting copper and stainless steel together leverages the strengths of two dissimilar metals, compensating for the shortcomings of a single material. For example, a heat spreader formed by combining copper and stainless steel can create internal flow channels, utilizing copper's thermal conductivity for heat dissipation of chips and electronic devices while stainless steel maintains structural rigidity. However, mechanical connections often struggle to meet the high airtightness and fatigue resistance requirements of these flow channels. Therefore, the combination of copper and stainless steel... The encapsulation of heat spreaders made of dissimilar materials mostly adopts high-temperature brazing and high-temperature diffusion welding. However, the welding relies on high-cost silver-based materials. Not only does the material cost account for more than 50% of the weld cost, resulting in high welding costs, but the fundamental difference in physical properties between copper and stainless steel also leads to the problem. Copper has a thermal conductivity of 398 W / m·K, which is 26 times that of stainless steel, and the coefficient of linear expansion is nearly twice that of stainless steel. This results in concentrated thermal stress during welding, which can easily cause cracks and poses a risk of high-temperature desoldering. This is especially true for welding thin copper parts with a thickness of ≤3mm to thin stainless steel parts, which affects the quality and yield of the finished product and limits the large-scale mass production of heat spreaders.

[0003] While some welding methods for copper and stainless steel are disclosed in the prior art, such as the tungsten inert gas (TIG) welding process for copper and stainless steel parts disclosed in patent CN120133668A, which completes the welding of copper and stainless steel by opening a V-groove and using multiple filler wires, the cumbersome processes of filler wire and beveling increase the complexity of the equipment and limit the production space. At the same time, the filler wire calibration and wire feeding operations also make it difficult to increase the welding speed, resulting in high production costs and insufficient efficiency. Patent CN112775550A discloses a laser welding method for dissimilar materials T2 copper and 301 stainless steel, which pre-positions the tip of the welding wire above the welding plane and deflects the laser beam completely toward the 301 stainless steel base material to ignite the workpiece to be welded. While laser welding is possible, it still requires filler wire to complete the welding of 1-2mm thick copper and stainless steel, which limits production costs and efficiency. Without filler wire, if the miscibility between copper and iron at the metallurgical level is less than 4%, brittle Fe-Cu intermetallic compounds, such as the σ phase, are easily formed, causing the joint strength to drop sharply by 30%-50%. In addition, copper has a laser reflectivity of over 95% and a melting point 367℃ lower than stainless steel, making it extremely difficult to control the molten pool and easily causing defects such as incomplete fusion and porosity. Therefore, due to the differences in the thermophysical properties and poor metallurgical compatibility of copper and stainless steel during laser welding, and the additional sealing requirements for laser welding of heat exchange plates, laser welding of copper and stainless steel parts without filler materials such as welding wire and welding rods remains extremely challenging. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the above-mentioned technical problems. The present invention provides a composite laser welding process, device and application of copper and stainless steel, which does not require filler materials such as welding wire and welding rod, and can effectively improve the welding efficiency and quality of copper and stainless steel parts with a thickness of ≤3mm, significantly reduce production costs, and provide a technical path for the large-scale mass production of copper and stainless steel heat exchange plates, etc.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] The first aspect of this invention is to provide a composite laser welding process for copper and stainless steel, the welding process comprising:

[0007] After the copper and stainless steel parts to be welded are fitted together to form a seam, an infrared laser beam and a blue laser beam are used to form a red-blue composite laser beam. The red-blue composite laser beam is first used to perform pre-laser welding at one or more points along the seam path. The pre-laser welding includes spot welding and / or segmented welding. Then, the red-blue composite laser beam is used to perform laser welding along the seam path to form a weld. During the pre-laser welding and laser welding, the spot formed by the infrared laser beam is controlled to swing with the swing center located on the seam path. At the same time, the center of the blue laser beam spot is controlled to be biased towards the copper part outside the seam path.

[0008] In the preferred technical solution, the assembly gap between the end faces of the copper part to be welded and the stainless steel part is ≤0.3mm.

[0009] In a preferred embodiment, the copper part is provided with a groove for assembly with the stainless steel part, or the stainless steel part is provided with a groove for assembly with the copper part.

[0010] In a preferred embodiment, during the pre-laser welding, a pressure plate is placed on top of the copper and stainless steel parts; during the laser welding, the pressure of the pressure plate can be released.

[0011] In a preferred embodiment, the spot formed by the infrared laser beam oscillates in a ring, and the blue light spot intersects, deviates from, or is tangent to the ring oscillation trajectory of the spot formed by the infrared laser beam.

[0012] In a preferred embodiment, the spot formed by the infrared laser beam is circular and the diameter of the circular motion is 0.4-1.2 mm.

[0013] In the preferred technical solution, the offset distance of the center of the blue light spot to the copper part outside the splicing path is 0.5-1mm, and the diameter of the blue light spot is 0.5-2mm.

[0014] In a preferred embodiment, an infrared laser beam is formed by an infrared laser and a blue laser beam is formed by a blue laser. During laser welding, the power of the infrared laser and the blue laser is increased compared to pre-laser welding.

[0015] In a preferred embodiment, the wavelength of the blue laser beam is 450 nm, and the wavelength of the blue laser beam is 1064 nm.

[0016] In the preferred technical solution, during spot welding, the power of the infrared laser is 1200-1500W; the power of the blue laser is 300-500W, and the diameter of the blue laser spot is 0.5-1mm; the spot welding time is 100-200ms.

[0017] In the preferred technical solution, during the segmented welding, the power of the infrared laser is 1200-1500W; the power of the blue laser is 300-500W, the diameter of the blue laser spot is 0.5-1mm; and the segmented welding speed is 40-80mm / s.

[0018] In a preferred technical solution, during the segmented welding, the entire seam path is divided into multiple segments and the inter-segmented seam segments are welded in sequence, with the welding depth accounting for 40%-60% of the seam depth.

[0019] In the preferred embodiment, during laser welding, the power of the infrared laser is 3000-5000W; the power of the blue laser is 500-800W; the diameter of the blue laser spot is 1-2mm; and the laser welding speed is 40-80mm / s.

[0020] In the preferred technical solution, the pre-laser welding and laser welding are carried out under a protective gas. The gas is turned on 500-1000ms in advance before the laser welding begins, and the flow rate of the protective gas is 15-22L / min.

[0021] In a preferred embodiment, the protective gas is selected from at least one of nitrogen and argon.

[0022] In the preferred embodiment, the copper part is made of T1 copper or T2 copper; the stainless steel part is made of 304L stainless steel or 316L stainless steel.

[0023] In the preferred technical solution, the thickness of the copper part is ≤3mm; the thickness of the stainless steel part is ≤3mm; and the weld penetration depth is ≥ the joint depth.

[0024] A second aspect of the present invention is to provide a composite laser welding apparatus for copper and stainless steel, comprising a red-blue composite welding head having an infrared oscillation function, the red-blue composite welding head being used to perform pre-laser welding and laser welding according to the composite laser welding process for copper and stainless steel as described in any one of the above claims.

[0025] In a preferred embodiment, a carrier is included, which is used to support the copper and stainless steel parts to be welded. The carrier is provided with at least one pressure member, which includes a rotating module and a pressure plate. The rotating module is used to drive the pressure plate to rotate reciprocally.

[0026] A third aspect of the present invention is to provide an application of a composite laser welding process for copper and stainless steel, comprising using the composite laser welding process for copper and stainless steel described in any one of the above claims for the welding production of a heat spreader, wherein the heat spreader includes a copper base, a stainless steel cover plate and a copper guide nozzle, firstly spot welding is performed between the copper guide nozzle and the stainless steel cover plate, then segmental welding is performed between the copper base and the stainless steel cover plate, and finally laser welding is performed between the copper guide nozzle and the stainless steel cover plate and between the copper base and the stainless steel cover plate.

[0027] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0028] (1) The present invention uses an infrared laser beam and a blue laser beam to form a red-blue composite laser beam. The center of the light spot formed by the infrared laser beam is offset from the blue light spot towards the copper side by a special method. Compared with existing high-temperature brazing, argon arc welding, and filler laser welding processes, there is no need for cumbersome processes such as filler, filler wire, and beveling. The filler wire calibration and wire feeding time are eliminated, and the welding speed can be increased by 20%–40%, which greatly reduces production costs and improves production efficiency.

[0029] (2) This invention utilizes the biasing of the blue light spot to provide targeted heat supplementation to the copper parts. Combined with the fact that the swing center of the spot formed by the infrared laser beam is located at the joint path, it not only overcomes the problem of the increased difference in absorption rate of copper / stainless steel to long-wavelength lasers, but also avoids the high reflectivity of copper, such as copper, to infrared lasers, effectively improving the energy utilization rate. Combined with pre-laser welding of spot welding and / or segmented welding, and then laser welding to achieve the penetration depth, only a lower overall power is needed to meet the needs of composite laser welding, effectively avoiding material overheating. It can improve the welding efficiency and quality of copper and stainless steel parts with a thickness of ≤3mm, and avoid defects such as porosity and lack of fusion.

[0030] (3) The device of the present invention uses a red-blue composite welding head with infrared swing function to perform pre-laser welding and laser welding, eliminating the need for cumbersome processes such as filler, filler wire, and beveling, reducing the complexity of the equipment by more than 30%, and is especially suitable for space-constrained scenarios.

[0031] (4) The present invention provides a technical path for the mass production of copper and stainless steel heat exchange plates, which can not only ensure the original mechanical properties of copper / stainless steel heat exchange plates and improve the yield rate, but also has a simple process, low equipment cost, and significantly improves economic benefits. Attached Figure Description

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0033] Figure 1 This is a schematic diagram of the red-blue composite laser beam welding of the present invention.

[0034] Figure 2 This is a schematic diagram of the clamping state of the composite laser welding device in this invention.

[0035] Figure 3 This is a schematic diagram of the welding of the copper guide nozzle and the stainless steel cover plate in this invention.

[0036] Figure 4 This is a schematic diagram of the welding between the copper base and the stainless steel cover plate in this invention.

[0037] Figure 5 This is a schematic diagram of the oscillation of the infrared laser beam and the shift of the blue light beam formed in Embodiment 1 of the present invention;

[0038] Figure 6 This is a weld appearance diagram of Embodiment 1 of the present invention.

[0039] Figure 7 This is a metallographic image of the weld seam in Embodiment 1 of the present invention.

[0040] Figure 8 This is a schematic diagram of the oscillation of the infrared laser beam and the shift of the blue light beam in Embodiment 2 of the present invention;

[0041] Figure 9 This is a weld appearance diagram of Embodiment 2 of the present invention.

[0042] Figure 10 This is a metallographic image of the weld seam in Embodiment 2 of the present invention.

[0043] Figure 11 This is a schematic diagram of the oscillation of the infrared laser beam and the shift of the blue light beam in Embodiment 3 of the present invention.

[0044] Figure 12 This is a weld appearance diagram of Embodiment 3 of the present invention.

[0045] Figure 13 This is a metallographic image of the weld seam in Embodiment 3 of the present invention.

[0046] Figure 14 This is a schematic diagram of the oscillation of the infrared laser beam and the shift of the blue light beam in Embodiment 3 of the present invention.

[0047] Figure 15 This is a weld appearance diagram of Comparative Example 1 of the present invention.

[0048] Figure 16 This is a weld appearance diagram of Comparative Example 3 of the present invention.

[0049] The markings in the diagram are as follows: 1. Carrier; 2. Pre-welding trajectory; 3. First pressure plate; 4. First rotating module; 5. Weld point; 6. Second pressure plate; 7. Second rotating module; 8. Copper base; 9. Stainless steel cover plate; 10. Copper guide nozzle; 11. Copper guide nozzle welding trajectory; 12. Stainless steel cover plate welding trajectory; 13. Red-blue composite welding head; 14. Infrared laser beam; 15. Blue laser beam; 16. Copper part; 17. Stainless steel part; 18. Joint; 19. Red-blue composite laser beam; 20. Step groove; 21. Annular base; 22. Countersunk hole; φ1. Swing diameter; d. Offset distance; φ2. Blue light spot diameter; h. Detailed Implementation

[0050] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0051] In the description of this invention, it should be understood that the terms "center," "thickness," "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] Existing methods for welding copper and stainless steel require filler wire and filler, which limits production costs and efficiency. This is especially true for welding thin copper and stainless steel parts (≤3mm thick), where there is a risk of weld failure. While laser welding eliminates the need for filler wire, the differences in thermophysical properties and poor metallurgical compatibility between copper and stainless steel lead to defects such as incomplete fusion and porosity. This invention addresses this issue by using a red-blue composite laser beam formed by infrared and blue laser beams. A special method of offsetting the infrared laser beam's spot oscillation center with the blue laser spot towards the copper side achieves high-efficiency and high-quality laser welding. Figure 1 As shown, a preferred embodiment of the composite laser welding process for copper and stainless steel according to the present invention includes the following welding process: after assembling the end faces of the copper part 16 and the stainless steel part 17 to be welded to form a joint 18, an infrared laser beam 14 and a blue laser beam 15 are used to form a red-blue composite laser beam 19. The red-blue composite laser beam 19 is first used to perform pre-laser welding at one or more points along the path of the joint 18. The pre-laser welding includes spot welding and / or segmented welding. Then, the red-blue composite laser beam 19 is used to perform laser welding along the path of the joint 18 to form a weld. During the pre-laser welding and laser welding, the light spot formed by the infrared laser beam 14 is controlled to swing and the swing center is located on the path of the joint 18. At the same time, the center of the blue light spot of the blue laser beam 15 is controlled to be biased towards the copper part 16 outside the path of the joint 18.

[0054] The aforementioned composite laser welding process eliminates the need for filler wire, eliminating the cumbersome procedures of filler, filler wire, and beveling. After the end faces of the copper part 16 and the stainless steel part 17 to be welded are fitted together to form a joint 18, the self-fusion welding of copper and stainless steel can be directly achieved through the energy synergy of the red and blue composite laser beam 19.

[0055] On the one hand, addressing the differences in thermophysical properties between copper and stainless steel, two dissimilar metals, and the difficulty in controlling the metallurgical compatibility of copper and stainless steel after omitting the filler wire process, the aforementioned process utilizes the physical characteristics of copper—high absorption rate of blue light and high reflectivity of infrared laser beam 14 at low temperatures—during spot welding, segmented welding along the joint 18 path, or final laser welding. This controls the center of the blue light spot of the blue laser beam 15 to be biased towards the copper part 16 side outside the joint 18 path, allowing for targeted heat supplementation to the copper part 16 side. This ensures that the copper part 16 side reaches its melting temperature and avoids overheating of the stainless steel part 17 due to the center of the blue light spot directly irradiating the joint 18 path. Simultaneously, the increased temperature of the copper part 16 side due to blue light irradiation reduces its sensitivity to the infrared laser beam 14. With a reflectivity of 4, and the oscillation center of the spot formed by the infrared laser beam 14 located at the joint 18 path, the copper and stainless steel interface can be fully fused. The oscillation expands the heat coverage area, avoiding local overheating. This not only overcomes the problem of increased absorption rate difference between copper and stainless steel for long-wavelength lasers, but also avoids the high reflectivity of copper, such as pure copper, for infrared lasers, effectively improving energy utilization. It also suppresses the formation of brittle intermetallic compounds and avoids defects such as porosity and incomplete fusion. Compared with existing high-temperature brazing, argon arc welding, and filler laser welding processes, the above process is particularly suitable for space-constrained scenarios. It eliminates the need for filler wire calibration and wire feeding time, and the welding speed can be increased by 20%–40%, greatly reducing production costs and improving production efficiency.

[0056] On the other hand, considering the poor rigidity of the copper part 16, especially when welding thin copper parts 16 with a thickness of ≤3mm to thin stainless steel parts 17, the weld seam 18 is prone to shift due to thermal deformation during welding. When welding without filler wire, the gap of the weld seam 18 or excessive heat input may affect the fusion quality or cause defects such as incomplete fusion. The above process uses pre-laser welding, including spot welding and / or segmented welding, to lock the relative position of the copper part 16 and stainless steel parts 17 with local energy, preventing the weld seam 18 from shifting due to thermal deformation during subsequent main welding. Then, continuous laser welding is performed along the path of the weld seam 18 to achieve the final weld formation and fusion quality. Only a lower overall power is required to meet the needs of composite laser welding, effectively avoiding material overheating and further improving the reliability of filler wire-free laser welding. This can effectively improve the welding efficiency and quality of copper parts 16 and stainless steel parts 17 with a thickness of ≤3mm and significantly reduce production costs.

[0057] Furthermore, the assembly gap between the end faces of the copper part 16 and the stainless steel part 17 to be welded is ≤0.3mm, which can further control the energy of the red-blue composite laser beam 19 to be concentrated on the interface between the copper and stainless steel, and improve the density of the weld.

[0058] Furthermore, the copper part 16 is provided with a groove for assembly with the stainless steel part 17, or the stainless steel part 17 is provided with a groove for assembly with the copper part 16, so that the copper and stainless steel can be quickly positioned and assembled through the groove.

[0059] Furthermore, during the pre-laser welding, a pressure plate is pressed on top of the copper part 16 and the stainless steel part 17; during the laser welding, the pressure of the pressure plate can be released; for example, by attaching multiple pressure plates on top of the copper part 16 and the stainless steel part 17, deformation can be further suppressed, and releasing the pressure of the pressure plate during laser welding can avoid affecting the continuous laser welding along the joint 18 path.

[0060] Furthermore, the spot formed by the infrared laser beam 14 oscillates in a ring. This ring-shaped oscillation of the spot can establish a stable deep-melting channel and a uniform thermal field at the seam 18, avoiding undermelting and overheating. The ring-shaped oscillation trajectory of the blue light spot intersects, separates from, or is tangent to the ring-shaped oscillation trajectory of the infrared laser beam 14. This relationship between the blue light spot and the ring-shaped oscillation trajectory can further promote the flow and homogenization of the molten pool, reducing defects caused by uneven fusion.

[0061] Furthermore, the spot formed by the infrared laser beam 14 is oscillating in a ring with an oscillation diameter φ1 of 0.4-1.2 mm. The ring oscillation stirs the molten pool, which can make the infrared energy fully act on the interface of the joint 18, avoiding insufficient melting depth and thermal field caused by an excessively large oscillation diameter φ1, and avoiding overheating and deformation caused by an excessively small oscillation diameter φ1.

[0062] Furthermore, the offset distance d of the center of the blue light spot towards the copper part 16 outside the path of the joint 18 is 0.5-1mm, and the diameter φ2 of the blue light spot is 0.5-2mm. The energy of the molten pool on the copper side can be further controlled by controlling the offset distance d and the diameter φ2 of the blue light spot, thereby reducing defects such as incomplete fusion and porosity, optimizing the flow of the molten pool and the formation of the weld, avoiding local overheating deformation caused by an excessively small offset distance d or an excessively large diameter φ2 of the blue light spot, and avoiding the impact of an excessively large offset distance d or an excessively small diameter φ2 of the blue light spot on the good connection of the molten pool.

[0063] Furthermore, an infrared laser beam 14 is formed by an infrared laser and a blue laser beam 15 is formed by a blue laser. During laser welding, the power of the infrared and blue lasers is increased compared to pre-laser welding. During pre-laser welding, the power of the infrared and blue lasers is lower, which can fix the assembly position of the copper part 16 and the stainless steel part 17 through small-area, low-energy melting, and suppress the deviation of the joint 18 caused by thermal deformation or displacement during subsequent laser welding. Afterward, the overall heat input is increased by increasing the power during laser welding, so that the molten metal on the copper part 16 side and the molten pool on the stainless steel part 17 side can be fully fused, so that the weld reaches the required penetration depth. Preferably, the laser wavelength of the blue laser beam is 450nm and the laser wavelength of the blue laser beam 15 is 1064nm, which can further improve the energy utilization of welding two dissimilar metals.

[0064] Furthermore, during spot welding, the infrared laser power is 1200-1500W; the blue laser power is 300-500W, and the blue laser spot diameter φ2 is 0.5-1.5mm; the spot welding time is 100-200ms. For example, multiple spaced weld points 5 can be set on the annular seam 18 path. The power control of the infrared laser can quickly form sufficient penetration between the copper part 16 and the stainless steel part 17, while avoiding excessive deformation due to excessive penetration. The power of the blue laser can prevent under-melting on the copper part 16 side due to insufficient energy, while avoiding porosity and spatter due to excessive penetration. The blue laser spot diameter φ2 can form sufficient energy density and effective range, avoiding excessive energy concentration in local areas due to excessive penetration, and avoiding excessive heat-affected zone due to excessive penetration. The spot welding time is combined with the connection and heat control requirements.

[0065] Furthermore, during the segmented welding, the infrared laser power is 1200-1500W; the blue laser power is 300-500W, and the blue laser spot diameter φ2 is 0.5-1.5mm; the segmented welding speed is 40-80mm / s. For example, during the segmented welding, the entire seam 18 path is divided into multiple segments and the interleaved seam segments are welded. The power control of the infrared laser can quickly form sufficient penetration between the copper part 16 and the stainless steel part 17, while avoiding excessive deformation caused by excessive penetration; the power of the blue laser can prevent the copper part 16 from being damaged. Six sides may experience under-melting due to insufficient energy, while avoiding excessive energy to prevent porosity and spatter; the blue light spot diameter φ2 can form sufficient energy density and effective range, avoiding excessive energy concentration in local areas due to too small a spot, and avoiding excessive heat-affected zone due to too large a spot; the welding speed of the segmented welding is combined with the connection and heat control requirements to balance welding efficiency, and the welding depth is preferably 40%-60% of the joint depth h, which lays the foundation for subsequent welding. This avoids weak connection at the segmented welding due to insufficient welding depth, and premature complete fusion of the weld root due to excessive welding depth, thereby reducing the risk of defects.

[0066] Furthermore, during laser welding, the infrared laser power is 3000-5000W; the blue laser power is 500-800W, the blue laser spot diameter φ2 is 1-2mm, and the laser welding speed is 40-80mm / s. Using a higher infrared laser power allows for rapid formation of a deeper molten pool, overcoming the thickness limitations of the stainless steel side and ensuring the weld reaches the desired depth, while avoiding excessive heat leading to burn-through or excessive expansion of the heat-affected zone. Using a higher blue laser power with an appropriate blue laser spot diameter φ2 allows for efficient fusion and weld formation on the copper side, while avoiding excessively high power or a small blue laser spot diameter φ2, which could lead to localized overheating and burn-out. An appropriate laser welding speed balances welding efficiency and defect control, avoiding insufficient penetration due to excessive speed and deformation defects and inefficiency due to excessively slow speed.

[0067] Furthermore, the pre-laser welding and laser welding are carried out under a protective gas, which is selected from at least one of nitrogen and argon. The gas is turned on 500-1000ms in advance before the laser welding begins, and the flow rate of the protective gas is 15-22L / min, which can form a stable inert protective atmosphere and suppress air interference.

[0068] Furthermore, the copper part 16 is made of T1 copper or T2 copper; the stainless steel part 17 is made of 304L stainless steel or 316L stainless steel, which can meet the needs of industrial production.

[0069] Furthermore, the copper part 16 has a thickness ≤ 3mm, the stainless steel part 17 has a thickness ≤ 3mm, and the weld penetration depth is ≥ joint depth h, which can adapt to the processing requirements of copper and stainless steel heat spreaders and other processes, and is suitable for mass production.

[0070] Based on the same inventive concept, a preferred embodiment of the composite laser welding device for copper and stainless steel described in this invention is as follows: Figure 1 and Figure 2 As shown, it includes a red-blue composite welding head 13 with infrared oscillation function; the red-blue composite welding head 13 is used to perform pre-laser welding and laser welding according to the composite laser welding process of copper and stainless steel described in any of the above-mentioned methods; since there is no need for cumbersome processes such as filler, filler wire, and beveling, the complexity of the equipment is reduced by more than 30%, which is especially suitable for space-constrained scenarios.

[0071] Furthermore, it includes a carrier 1, which is used to support the copper part 16 and the stainless steel part 17 to be welded. The carrier 1 is provided with at least one pressing component, which includes a rotating module and a pressure plate. The rotating module is used to drive the pressure plate to rotate back and forth. For example, the rotating module is a rotary cylinder. After the end faces of the copper part 16 and the stainless steel part 17 are placed in contact with each other at the center of the carrier 1, the pressure plate can be driven to rotate by the rotary cylinder so that the pressure plate presses on the copper part 16 and the stainless steel part 17. The pressure can be released by driving the pressure plate to rotate in the opposite direction by the rotary cylinder.

[0072] Based on the same inventive concept, a preferred embodiment of the copper-stainless steel composite laser welding process of the present invention includes using the copper-stainless steel composite laser welding process and apparatus described in any one of the above claims for the welding production of a heat spreader plate. The heat spreader plate includes a copper base 8, a stainless steel cover plate 9, and a copper guide nozzle 10. First, spot welding is performed between the copper guide nozzle 10 and the stainless steel cover plate 9. Then, segmented welding is performed between the copper base 8 and the stainless steel cover plate 9. Finally, laser welding is performed between the copper guide nozzle 10 and the stainless steel cover plate 9, and between the copper base 8 and the stainless steel cover plate 9. For example, specifically, the process may include the following steps:

[0073] Step 1: Prepare copper part 16 and stainless steel part 17:

[0074] like Figure 2 As shown, the copper component 16 is a copper base 8 and two copper guide nozzles 10 made of T1 or T2 copper. The copper base 8 has an open top and a stepped groove 20 on its edge, which serves as a recess. The two copper guide nozzles 10 are hollow inside and have a raised bottom to form an annular base 21. The stainless steel component 17 is a U-shaped stainless steel cover plate 9 made of 304L or 316L stainless steel. The edge of the stainless steel cover plate 9 can fit with the stepped groove 20. The height of the stepped groove 20 is the same as the thickness of the stainless steel cover plate 9. The two ends of the U-shape of the stainless steel cover plate 9 are respectively provided with countersunk holes 22, which serve as recesses. The annular base 21 can fit with the countersunk holes 22. The height of the countersunk holes 22 is adapted to the thickness of the annular base 21. The surfaces of the copper base 8, the stainless steel cover plate 9, and the corresponding copper guide nozzles 10 are cleaned with acetone / anhydrous ethanol to obtain the copper component 16 and the stainless steel component 17 to be welded.

[0075] Step Two, as follows Figure 2 As shown, the copper part 16 to be welded obtained in step one is fitted together with the end face of the stainless steel part 17 to form a joint 18:

[0076] The bottom of the copper base 8 is placed in the center of the carrier 1. The stainless steel cover plate 9 is placed in the stepped groove 20 of the copper base 8, so that the outer contour of the stainless steel cover plate 9 and the inner contour of the stepped groove 20 form a joint 18. Then, the annular base 21 of the copper guide nozzle 10 is placed in the countersunk hole 22 reserved in the stainless steel cover plate 9, so that the outer contour of the annular base 21 and the inner contour of the countersunk hole 22 form a joint 18. The carrier 1 is provided with two pressure members on both sides in front of the copper guide nozzle 10. The two pressure members are the first pressure plate 3 driven by the first rotating module 4 and the second pressure plate 6 driven by the second rotating module 7. The first pressure plate 3 closes first, and when closing, it rotates 180° clockwise. The second pressure plate 6 then closes, and when closing, it rotates 180° counterclockwise, rotating until it is close to the stainless steel cover plate 9 to prevent the stainless steel cover plate 9 from shifting.

[0077] Step 3: The red-blue composite welding head 13 with infrared oscillation function uses a 6000W continuous infrared fiber laser for infrared lasers and a 1000W BlueMoo Laser blue laser. An infrared laser beam 14 is formed from the infrared laser, and the blue laser beam has a wavelength of 450nm. A blue laser beam 15 is formed from the blue laser, with a wavelength of 1064nm. The infrared laser beam 14 and the blue laser beam 15 together form a red-blue composite laser beam 19. Figure 3 As shown in Figure a, a circular welding trajectory 11 for the copper guide nozzle 10 is set along the joint 18 between the copper guide nozzle 10 and the stainless steel cover plate 9, as follows: Figure 2 and Figure 4 As shown in Figure a, a welding trajectory 12 for the stainless steel cover plate is set along the joint 18 path between the copper base 8 and the stainless steel cover plate 9. During pre-laser welding and laser welding, the spot formed by the infrared laser beam 14 is controlled to swing in a ring shape with the swing center located on the joint 18 path, i.e., the corresponding welding trajectory. At the same time, the center of the blue spot of the blue laser beam 15 is controlled to be biased towards the copper part 16 outside the joint 18 path, i.e., the copper base 8 / copper guide nozzle 10 side, with an offset distance d of 0.5-1mm. Argon is selected as the protective gas, and the protective gas flow rate is 15~22L / min. The gas is turned on 500-1000ms in advance before the laser welding. The following pre-laser welding and laser welding are all performed under these conditions.

[0078] First, a pre-laser welding process is performed between the copper guide nozzle 10 and the stainless steel cover plate 9 using a red-blue composite laser beam 19. During spot welding, the power of the infrared laser is 1200-1500W, and the oscillation diameter φ1 is 0.4-1.2mm; the power of the blue laser is 300-500W, and the blue light spot diameter φ2 is 0.5-1.5mm; the spot welding time is 100-200ms for both processes. Figure 3 As shown in b, a weld point 5 is welded on each of the left and right sides of the copper guide nozzle welding trajectory 11.

[0079] Pre-laser welding, performed by a red-blue composite laser beam 19 in segments between the copper base 8 and the stainless steel cover plate 9: (e.g.) Figure 4 As shown in b, the entire stainless steel cover plate welding trajectory 12 is divided into 12 segments and 6 interlocking seam segments are welded. These 6 interlocking seam segments are the pre-welding trajectory 2. During segmented welding, the power of the infrared laser is 1200-1500W and the swing diameter φ1 is 0.4-1.2mm; the power of the blue laser is 300-500W and the blue light spot diameter φ2 is 0.5-1.5mm; the segmented welding speed is 40-80mm / s, the welding length of each segment is 20-40mm, and the welding depth accounts for 40%-60% of the seam depth h.

[0080] Next, the second pressure plate 6 is first released, and the second pressure plate 6 is rotated 180° clockwise. Then, the first pressure plate 3 is released, and the first pressure plate 3 is rotated 180° counterclockwise. Then, the red-blue composite laser beam 19 performs laser welding between the copper guide nozzle 10 and the stainless steel cover plate 9, and between the copper base 8 and the stainless steel cover plate 9, to form a weld. Figure 3 As shown in Figure c, a weld seam is formed between the copper guide nozzle 10 and the stainless steel cover plate 9 by laser welding along the copper guide nozzle welding trajectory 11; as shown in Figure c. Figure 4 As shown in Figure c, a weld seam is formed between the copper base 8 and the stainless steel cover plate 9 by laser welding along the welding trajectory 12 of the stainless steel cover plate. During these two laser welding operations, the power of the infrared laser is 3000-5000W, the swing diameter φ1 is 0.4-1.2mm, the power of the blue laser is 500-800W, the blue light spot diameter φ2 is 1-2mm, and the laser welding speed is 40-80mm / s. Finally, the entire copper and stainless steel heat exchange plate is removed from the carrier 1. A flow channel that can be used for the flow of heat exchange medium is formed between the stainless steel cover plate 9 and the interior of the copper base 8 of the heat exchange plate. Two copper nozzles 10 serve as the outlet and inlet of the flow channel, respectively.

[0081] The process parameters for each embodiment are shown in Table 1 below:

[0082] Table 1. Process parameters for different embodiments

[0083]

[0084] In Example 1, when the red-blue composite laser beam 19 performs spot welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the oscillation of the light spot formed by the infrared laser beam 14 and the offset of the blue light spot are shown in the diagram. Figure 5 As shown in Figure a; during segmented welding between the copper base 8 and the stainless steel cover plate 9 using the red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue laser beam is shown in Figure a. Figure 5 As shown in b; when the red-blue composite laser beam 19 performs laser welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the schematic diagram of the oscillation of the spot formed by the infrared laser beam 14 and the offset of the blue light spot is shown in Figure 14. Figure 5 As shown in c; during laser welding between the copper base 8 and the stainless steel cover plate 9 using a red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue light spot is shown in the figure. Figure 5 As shown in d; it can be seen that the circular oscillation trajectory of the blue light spot intersects with that of the spot formed by the infrared laser beam 14. A sealing test was performed on the heat spreader plate after welding in Example 1. One copper guide nozzle 10 was randomly sealed, and another copper guide nozzle 10 was purged with compressed air at 0.6 MPa for 5 minutes. The results showed no air leakage, indicating that a good heat spreader plate was obtained. This process was repeated multiple times, and a heat spreader plate product was randomly selected. The surface and cross-section of the weld between the copper base 8 and the stainless steel cover plate 9 were observed under a microscope. The appearance of the weld surface is as shown in d. Figure 6 As shown, the weld is smooth, without spatter or pores; the weld cross-section is as follows. Figure 7 As shown in the figure, this embodiment achieves a weld penetration depth of ≥1mm, which is greater than the joint depth h, indicating a good bond.

[0085] In Example 2, when the red-blue composite laser beam 19 performs spot welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the oscillation of the light spot formed by the infrared laser beam 14 and the offset of the blue light spot are shown in the diagram. Figure 8 As shown in Figure a; during segmented welding between the copper base 8 and the stainless steel cover plate 9 using the red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue laser beam is shown in Figure a. Figure 8 As shown in b; when the red-blue composite laser beam 19 performs laser welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the schematic diagram of the oscillation of the spot formed by the infrared laser beam 14 and the offset of the blue light spot is shown in Figure 14. Figure 8 As shown in c; during laser welding between the copper base 8 and the stainless steel cover plate 9 using a red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue light spot is shown in the figure. Figure 8 As shown in d; the circular oscillation trajectory of the blue light spot and the infrared laser beam 14 is visible, either outwardly separated or outwardly tangent. A sealing test was performed on the heat spreader plate after welding in Example 2. One copper guide nozzle 10 was randomly sealed, while the other copper guide nozzle 10 was purged with 1MPa compressed air for 5 minutes. The results showed no air leakage, indicating a good heat spreader plate was obtained. This process was repeated multiple times, and a heat spreader plate product was randomly selected. The surface and cross-section of the weld between the copper base 8 and the stainless steel cover plate 9 were observed under a microscope. The weld surface appearance is as shown... Figure 9 As shown, the weld is smooth, without spatter or pores; the weld cross-section is as follows. Figure 10 As shown in the figure, this embodiment achieves a weld penetration depth of ≥2mm, which is greater than the joint depth h, indicating a good bond.

[0086] In Example 3, when the red-blue composite laser beam 19 performs spot welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the oscillation of the light spot formed by the infrared laser beam 14 and the offset of the blue light spot are shown in the diagram. Figure 11 As shown in Figure a; during segmented welding between the copper base 8 and the stainless steel cover plate 9 using the red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue laser beam is shown in Figure a. Figure 11 As shown in b; when the red-blue composite laser beam 19 performs laser welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the schematic diagram of the oscillation of the spot formed by the infrared laser beam 14 and the offset of the blue light spot is shown in Figure 14. Figure 11 As shown in c; during laser welding between the copper base 8 and the stainless steel cover plate 9 using a red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue light spot is shown in the figure. Figure 11 As shown in d; the circular oscillation trajectory of the blue light spot and the light spot formed by the infrared laser beam 14 is visible. A sealing test was performed on the heat spreader plate after welding in Example 3. One copper guide nozzle 10 was randomly sealed, and the other copper guide nozzle 10 was purged with compressed air at 1.5 MPa for 5 minutes. The results showed no air leakage, indicating a good heat spreader plate was obtained. This process was repeated multiple times, and a heat spreader plate product was randomly selected. The surface and cross-section of the weld between the copper base 8 and the stainless steel cover plate 9 were observed under a microscope. The appearance of the weld surface is as shown in the image. Figure 12 As shown, the weld is smooth, without spatter or pores; the weld cross-section is as follows. Figure 13 As shown in the figure, this embodiment achieves a weld penetration depth of ≥3mm, which is greater than the joint depth h, indicating a good bond.

[0087] In Example 4, when the red-blue composite laser beam 19 performs spot welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the oscillation of the light spot formed by the infrared laser beam 14 and the offset of the blue light spot are shown in the diagram. Figure 14 As shown in Figure a; during segmented welding between the copper base 8 and the stainless steel cover plate 9 using the red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue laser beam is shown in Figure a. Figure 14 As shown in b; when the red-blue composite laser beam 19 performs laser welding between the copper guide nozzle 10 and the stainless steel cover plate 9, the schematic diagram of the oscillation of the spot formed by the infrared laser beam 14 and the offset of the blue light spot is shown in Figure 14. Figure 14 As shown in c; during laser welding between the copper base 8 and the stainless steel cover plate 9 using a red-blue composite laser beam 19, the schematic diagram of the oscillation of the infrared laser beam 14 and the offset of the blue light spot is shown in the figure. Figure 14As shown in d, the circular oscillation trajectory of the blue light spot intersects with that of the infrared laser beam 14, and the blue light spot intersects with the welding trajectory 11 of the copper guide nozzle or the welding trajectory 12 of the stainless steel cover plate. A sealing test was performed on the heat spreader plate after welding in Example 4. One copper guide nozzle 10 was randomly sealed, and another copper guide nozzle 10 was purged with compressed air at 0.6 MPa for 5 minutes. The results showed no air leakage, indicating a good heat spreader plate was obtained. This process was repeated multiple times, and a heat spreader plate product was randomly selected. The surface and cross-section of the weld between the copper base 8 and the stainless steel cover plate 9 were observed under a microscope. The weld was smooth, without spatter or bursting. In this example, the weld penetration depth reached ≥1 mm, which is greater than the joint depth h, indicating a good bond.

[0088] The following comparative example is set up according to Example 1, using the same copper base 8, stainless steel cover plate 9 and copper guide nozzle 10 as in Example 1, for heat spreader welding:

[0089] The difference between Comparative Example 1 and Example 1 is that the blue laser was turned off during both pre-laser welding and laser welding; that is, only the spot formed by the infrared laser beam 14 was used, and the center of the oscillation was located on the path of the weld seam 18. Since the absorption rates of stainless steel and copper for the wavelength of 1064nm are 40% and 5% respectively, copper cannot form an effective penetration depth under the same parameters, and the weld surface appearance is as follows. Figure 14 As shown, welding produces a lot of spatter and defects, resulting in extremely poor weld formation and making it impossible to produce a good product.

[0090] The difference between Comparative Example 2 and Example 1 is that the infrared laser was turned off during both pre-laser welding and laser welding, that is, only the blue laser beam 15 was used for welding. The results showed that the penetration depth could only reach 0.3 mm, accounting for 30% of the plate thickness. The bonding strength was weak, and it was impossible to form a penetration depth through the stainless steel cover plate 9, so it could not be used.

[0091] The difference between Comparative Example 3 and Example 1 is that during pre-laser welding and laser welding, the center of the blue light spot did not independently deviate towards the copper part 16. That is, the spot formed by the infrared laser beam 14 oscillated in a ring, and the oscillation center of the infrared laser beam 14 and the center of the blue light spot of the blue laser beam 15 were both located on the path of the seam 18. Because stainless steel absorbs dual lasers more readily than copper, the stainless steel cover plate 9 overheated under the same parameters, failing to form a continuous and stable weld. This resulted in the product failing to seal properly upon inspection. Figure 15 As shown, voids are randomly formed in the weld.

[0092] The comparison results between Example 1 and Comparative Examples 1 and 2 show that by using an infrared + blue light composite laser and precise process settings, and by offsetting the center of the infrared laser beam 14 with the blue light beam towards the copper side, high-efficiency and high-quality laser welding can be achieved. Only a low overall power is required to meet the welding needs, effectively avoiding material overheating. The comparison results between Example 1 and Comparative Example 3 show that by utilizing the physical property of high absorption rate of copper for blue light, the present invention controls the center of the blue light beam 15 to be offset towards the copper part 16 outside the splice 18 path, which can provide targeted heat supplementation to the copper part 16 side, overcoming the problem of increased difference in absorption rate of copper / stainless steel for long-wavelength lasers, avoiding the reflection of infrared laser by copper, and effectively improving energy utilization.

[0093] As can be seen from the results of Examples 1-3, the present invention can effectively improve the welding efficiency and quality of copper parts 16 and stainless steel parts 17 with a thickness of ≤3mm without the need for filler materials such as welding wire and welding rod, and significantly reduce production costs. It provides a technical path for the large-scale mass production of copper and stainless steel heat spreaders, etc. It can not only ensure the original mechanical properties of copper / stainless steel heat spreaders and improve the yield rate, but also has a simple process, low equipment cost, and significantly improve economic benefits.

[0094] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite laser welding process for copper and stainless steel, characterized in that, Its welding process includes: After the copper part (16) to be welded and the stainless steel part (17) are fitted together to form a joint (18), an infrared laser beam (14) and a blue laser beam (15) are used to form a red-blue composite laser beam (19). The red-blue composite laser beam (19) is used to perform pre-laser welding at one or more points along the joint (18) path. The pre-laser welding includes spot welding and / or segmented welding. Then, the red-blue composite laser beam (19) is used to perform laser welding along the joint (18) path to form a weld. During the pre-laser welding and laser welding, the light spot formed by the infrared laser beam (14) is controlled to swing and the swing center is located on the joint (18) path. At the same time, the center of the blue light spot of the blue laser beam (15) is controlled to be biased towards the copper part (16) outside the joint (18) path.

2. The composite laser welding process for copper and stainless steel according to claim 1, characterized in that, The assembly gap between the end faces of the copper part (16) and the stainless steel part (17) to be welded is ≤0.3mm; the copper part (16) is provided with a groove for assembly with the stainless steel part (17), or the stainless steel part (17) is provided with a groove for assembly with the copper part (16); during the pre-laser welding, the pressure plate is pressed on top of the copper part (16) and the stainless steel part (17); the pressure plate can be released during the laser welding.

3. The composite laser welding process for copper and stainless steel according to claim 1, characterized in that, The infrared laser beam (14) forms a spot that swings in a ring and the swing diameter φ1 is 0.4-1.2 mm. The offset distance d of the center of the blue light spot toward the copper part (16) outside the path of the seam (18) is 0.5-1 mm, and the diameter φ2 of the blue light spot is 0.5-2 mm. An infrared laser beam (14) is formed by an infrared laser and a blue laser beam (15) is formed by a blue laser. During laser welding, the power of the infrared laser and the blue laser is increased compared to that during pre-laser welding.

4. The composite laser welding process for copper and stainless steel according to claim 3, characterized in that, During spot welding, the power of the infrared laser is 1200-1500W; the power of the blue laser is 300-500W, and the diameter of the blue laser spot φ2 is 0.5-1.5mm; the spot welding time is 100-200ms.

5. The composite laser welding process for copper and stainless steel according to claim 3, characterized in that, During the segmented welding, the power of the infrared laser is 1200-1500W; the power of the blue laser is 300-500W, and the diameter of the blue laser spot φ2 is 0.5-1.5mm; the segmented welding speed is 40-80mm / s; during the segmented welding, the entire seam (18) path is divided into multiple segments and the seam segments are welded in sequence, and the welding depth accounts for 40%-60% of the seam depth h.

6. The composite laser welding process for copper and stainless steel according to claim 5, characterized in that, During laser welding, the power of the infrared laser is 3000-5000W; the power of the blue laser is 500-800W; the diameter of the blue laser spot φ2 is 1-2mm; and the laser welding speed is 40-80mm / s.

7. The composite laser welding process for copper and stainless steel according to claim 3, characterized in that, The pre-laser welding and laser welding are carried out under a protective gas, which is selected from at least one of nitrogen and argon. The gas is turned on 500-1000ms in advance before the laser welding begins, and the flow rate of the protective gas is 15-22L / min.

8. The composite laser welding process for copper and stainless steel according to claim 1, characterized in that, The copper part (16) is made of T1 copper or T2 copper; the stainless steel part (17) is made of 304l stainless steel or 316l stainless steel; the thickness of the copper part (16) is ≤3mm, the thickness of the stainless steel part (17) is ≤3mm, and the weld penetration depth is ≥ the joint depth h.

9. The application of the composite laser welding process for copper and stainless steel according to any one of claims 1 to 8, characterized in that, The process includes welding production for a heat spreader plate, which includes a copper base (8), a stainless steel cover plate (9), and a copper nozzle (10). First, spot welding is performed between the copper nozzle (10) and the stainless steel cover plate (9). Then, segmented welding is performed between the copper base (8) and the stainless steel cover plate (9). Finally, laser welding is performed between the copper nozzle (10) and the stainless steel cover plate (9) and between the copper base (8) and the stainless steel cover plate (9).

10. A composite laser welding device for copper and stainless steel, characterized in that, The invention includes a red-blue composite welding head (13) with infrared oscillation function, which is used to perform pre-laser welding and laser welding in the composite laser welding process of copper and stainless steel according to any one of claims 1 to 8.

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