P-type galvanized high-strength steel pipe laser repair welding fixture and method

Abstract

The application discloses a P-type galvanized high-strength steel pipe laser repair welding clamp, and relates to a P-type galvanized high-strength steel pipe laser repair welding clamp and method. The P-type steel pipe workpiece produced on a rolling production line may generate defective products due to welding production process conditions and other problems, and the defective products are characterized by insufficient weld penetration and width and even cracking. In view of the problem, the application provides a laser repair welding clamp and welding method. The welding device of the P-type steel pipe is provided with a clamping device, so that the P-type steel pipe workpiece can be tightly clamped on the welding clamp under the action of the limiting structure, thereby facilitating the laser welding of the P-type steel pipe workpiece by a welding robot, improving the stability and welding work efficiency during welding, solving the problem that the P-type high-strength steel is difficult to weld without being fixed, blowing the welding working surface by cooling gas, reducing the cooling time after welding, improving the production efficiency, and increasing the yield of P-type steel pipe products.

Description

Technical Field

[0001] This invention relates to the field of laser welding repair technology, and more specifically, to a P-type laser welding fixture for galvanized high-strength steel pipes. Background Technology

[0002] Galvanized steel sheets have long been widely used in automobile manufacturing, packaging, bridge construction, and industrial facilities due to their excellent corrosion resistance, good mechanical properties, and low price. Galvanizing forms a dense protective layer on the surface of a steel substrate, which not only shields against moisture and oxygen in the air but also provides electrochemical protection. Under natural conditions, the galvanized layer and the steel substrate can form a micro-battery, with zinc acting as the anode and being corroded, while iron acts as the cathode and is protected, greatly improving the corrosion resistance of the galvanized steel sheet.

[0003] With the increasing emphasis on energy conservation and environmental protection by the nation, the development of new energy vehicles is accelerating. Blade batteries using lithium iron phosphate technology are being applied in new energy vehicles. To effectively protect these batteries during operation, a battery tray is essential. This invention proposes a P-type steel pipe, which involves roll-forming a steel strip into a closed tubular structure and then laser-welding the tubular structure together to complete the steel pipe forming. The battery tray frame is then assembled using corresponding frame beams. However, due to equipment and process limitations during production, certain welding defects may occur. Defective products can be repaired through subsequent welding processes to improve the product qualification rate of P-type steel pipes. Therefore, the methods and equipment for repair welding are issues that need to be addressed.

[0004] No effective solutions have yet been proposed to address the problems in the relevant technologies. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a P-type laser welding fixture and method for galvanized high-strength steel pipes, which effectively reduces the impact of welding heat on the welded workpiece during laser welding, thereby solving the problems existing in the prior art.

[0007] (II) Technical Solution

[0008] To achieve the aforementioned function of effectively reducing the impact of welding heat on the welded workpiece during laser welding, the specific technical solution adopted by this invention is as follows:

[0009] A laser welding fixture for P-type galvanized high-strength steel pipes is disclosed. The fixture includes an installation structure, a limiting groove, a limiting structure, a pneumatic rotary structure, and an air-blowing structure. The installation structure comprises a base plate, a frame, and legs. The frame is fixedly connected to the bottom end of the base plate, and legs are fixedly connected to the four corners of the base plate. A limiting groove is formed on the base plate, and the limiting groove connects to the limiting structure. The pneumatic rotary structure is connected to the top end of the base plate. A P-type steel pipe workpiece is placed on one side of the pneumatic rotary structure, and the air-blowing structure is connected to both ends of the P-type steel pipe workpiece. The pneumatic rotary structure serves to fix the P-type steel pipe workpiece and press it into reverse deformation. Three identical sets of the pneumatic rotary structure and air-blowing structure are combined on the base plate to increase the number of welds and improve welding efficiency.

[0010] Furthermore, the limiting structure includes a limiting block, a sliding block, a connecting rod, an adjusting block, a sleeve rod, a spring, a threaded rod, a threaded sleeve, and a rotating head. The bottom end of the limiting block is fixedly connected to a sliding block, the sliding block is slidably connected in the limiting groove, the connecting rod is fixedly connected in the sliding block, and the end of the connecting rod is fixedly connected to an adjusting block.

[0011] Furthermore, one end of a sleeve rod is fixedly connected to one side of the adjusting block, and a spring is sleeved on the sleeve rod. A threaded rod is provided on one side of the sleeve rod, and the threaded rod is threadedly connected to a threaded sleeve. One end of the threaded sleeve is fixedly connected to one side of the base plate, and the other end of the threaded rod is fixedly connected to a rotating head. The limiting structure can adjust the position of the limiting block through threaded adjustment, so that it can perform side clamping and fixing treatment on the P-shaped steel pipe workpiece. There are four sets of limiting structures, two sets on one side of the P-shaped steel pipe workpiece and the other two sets on the other side of the P-shaped steel pipe workpiece.

[0012] Furthermore, the pneumatic rotary structure includes a motor, a rotating shaft, a connecting rod, and a telescopic rod. The driving end of the motor is connected to the rotating shaft. The welded side consists of three pneumatic rotary structures, while the unwelded side consists of two pneumatic rotary structures. The pneumatic rotary structure is easy to operate and has low cost.

[0013] Furthermore, a connecting rod is fixedly connected to the rotating shaft, and a telescopic rod is connected to one end of the bottom side of the connecting rod. The pressure block at the driving end of the telescopic rod of the pneumatic rotary structure is provided with a rubber pad.

[0014] Furthermore, the air blowing structure includes a push block, an air pipe interface, an air port, and a cylinder. One side of the push block is connected to the air pipe interface, and the other side of the push block is connected to the air port. The two sides of the air pipe interface are connected to the drive rods of the cylinder. The cylinder is fixedly installed on the base plate. The air port is aligned with the port of the P-shaped steel pipe workpiece and extends into the welded workpiece tube to facilitate air blowing and cooling of the weld seam.

[0015] A laser welding method, characterized in that:

[0016] S1: Set process parameters such as laser power, robot running speed, and protective gas flow rate; set the oscillation width and frequency of the galvanometer welding head; place the high-strength steel pipe on the fixture; press it against the air blowing structure and the side limiting block; start the pneumatic rotary structure with one key; clamp the workpiece; fix the workpiece in the positioning position of the pneumatic rotary structure and the limiting structure; and clamp the workpiece.

[0017] S2: Open the robot to teach the weld seam, use the CCD and the laser red light to align the weld seam, adjust the defocus of the laser beam at the same time, clamp and start the welding robot signal, and the welding robot starts laser welding;

[0018] S3: Laser welding is performed on a certain weld seam of the workpiece, and then the next weld seam is welded at intervals until all weld seams on the fixture are completed. After laser welding is completed, the air blowing structure on the welding fixture is activated to increase the cooling rate of the workpiece.

[0019] S4: During the workpiece welding process, the air-cooling component dissipates heat from the workpiece, reducing the thermal deformation of the workpiece caused by laser welding. After the workpiece cools down, the pneumatic rotary structure is released, and the workpiece is unloaded.

[0020] Furthermore, the laser welding head is equipped with a coaxial vision CCD and a linear red light to facilitate the correction of the welding focus. Before laser welding, the weld seam is taught and pre-traced along the center line of the weld seam, ensuring that the error between the teaching point and the center line of the weld seam does not exceed 0.5mm. The output power of the laser is in the range of 0~6KW. The laser welding head uses a galvanometer with a coaxial vision CCD. The laser welding speed is 1m / min~5m / min.

[0021] Preferably, the laser beam defocusing range of the laser is -3 to 2 mm.

[0022] Preferably, the processing distance of the galvanometer welding head is 500mm, which reduces the damage to the welding head caused by welding spatter during long-distance processing.

[0023] Preferably, a protective gas nozzle is installed at a 45° angle above the welding center below the galvanometer welding head to provide inert gas protection to the welding surface. The gas flow rate is 15L / min to 25L / min to prevent oxidation of the welding surface and to blow out welding plasma cloud and welding spatter.

[0024] (III) Beneficial Effects

[0025] Compared with the prior art, the present invention provides a P-type laser welding fixture for galvanized high-strength steel pipes, which has the following advantages:

[0026] This invention, through its installation structure, limiting structure, and pneumatic rotation structure, can repair welded defective parts. During laser welding, it effectively reduces the impact of welding heat on the welded workpiece, improves the quality of laser welding, and transforms defective parts into qualified parts, thus bringing good economic benefits to enterprises. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the main structure of the P-type galvanized high-strength steel pipe laser repair welding fixture according to an embodiment of the present invention;

[0029] Figure 2 This is a side view of the main structure of the P-type galvanized high-strength steel pipe laser repair welding fixture according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the limiting structure of the P-type galvanized high-strength steel pipe laser repair welding fixture according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the pneumatic rotary structure of the P-type galvanized high-strength steel pipe laser repair welding fixture according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the air blowing structure of the P-type galvanized high-strength steel pipe laser repair welding fixture according to an embodiment of the present invention.

[0033] In the picture:

[0034] 1. Installation structure; 101. Base plate; 102. Frame; 103. Support leg; 2. Limiting groove; 3. Limiting structure; 301. Limiting block; 302. Sliding block; 303. Through rod; 304. Adjusting block; 305. Sleeve rod; 306. Spring; 307. Threaded rod; 308. Threaded sleeve; 309. Rotating head; 4. Pneumatic rotary structure; 401. Motor; 402. Rotating shaft; 403. Connecting rod; 404. Telescopic rod; 5. Air blowing structure; 501. Pushing block; 502. Air pipe interface; 503. Air port; 504. Cylinder; 6. P-type steel pipe workpiece. Detailed Implementation

[0035] To further illustrate, the present invention is provided with accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0036] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figures 1-5 As shown, the laser welding fixture includes an installation structure 1, a limiting groove 2, a limiting structure 3, a pneumatic rotary structure 4, and an air blowing structure 5. The installation structure 1 includes a base plate 101, a frame 102, and support legs 103. The frame 102 is fixedly connected to the bottom end of the base plate 101, and support legs 103 are fixedly connected to the four corners of the base plate 101. A limiting groove 2 is opened on the base plate 101, and the limiting groove 2 is connected to the limiting structure 3. The pneumatic rotary structure 4 is connected to the top end of the base plate 101. A P-shaped steel pipe workpiece 6 is placed on one side of the pneumatic rotary structure 4, and the two ends of the P-shaped steel pipe workpiece 6 are connected to the air blowing structure 5. The laser welding fixture is adapted to a specific workpiece, namely the P-shaped steel pipe workpiece 6, with a steel pipe length of 1.2m-1.5m.

[0037] The entire welding fixture is placed on the ground. A limiting groove 2 is opened on the base plate 101, and a limiting block 301 is slidably connected. The relative positions of the limiting structure 3 and the air blowing structure 5 are adjusted according to the length and width of the steel pipe so that they are in the middle position of the workpiece.

[0038] The limiting structure 3 includes a limiting block 301, a sliding block 302, a connecting rod 303, an adjusting block 304, a sleeve rod 305, a spring 306, a threaded rod 307, a threaded sleeve 308, and a rotating head 309. The bottom end of the limiting block 301 is fixedly connected to the sliding block 302, which is slidably connected within the limiting groove 2. The connecting rod 303 is fixedly connected inside the sliding block 302. The end of the connecting rod 303 is fixedly connected to the adjusting block 304. One side of the adjusting block 304 is fixedly connected to one end of the sleeve rod 305. The sleeve rod 305 is sleeved with a spring 306. One side of the sleeve rod 305 is provided with a threaded rod 307. The rod 307 is threadedly connected to the threaded sleeve 308. One end of the threaded sleeve 308 is fixedly connected to one side of the base plate 101, and the other end of the threaded rod 307 is fixedly connected to the rotating head 309. The limiting structure 3 rotates the threaded rod 307 by adjusting the rotating head 309. Since one end of the threaded sleeve 308 is fixedly installed on one side of the base plate 101, the relative position of the threaded sleeve 308 and the threaded rod 307 is adjusted. Then, by driving the position of the adjusting block 304 and the through rod 303, the position of the sliding block 302 and the limiting block 301 are adjusted, so that the limiting block 301 can clamp and fix the workpiece from the side.

[0039] The pneumatic rotary structure 4 includes a motor 401, a rotating shaft 402, a connecting rod 403, and a telescopic rod 404. The driving end of the motor 401 is connected to the rotating shaft 402, and the connecting rod 403 is fixedly connected to the rotating shaft 402. The telescopic rod 404 is connected to one end of the connecting rod 403. The pressure block at the driving end of the telescopic rod 404 of the pneumatic rotary structure 4 is equipped with a rubber pad. The motor 401 can drive the rotating shaft 402, and the rotating shaft 402 drives the connecting rod 403 and the telescopic rod 404 to rotate and adjust. When the telescopic rod 404 rotates to the designated position, the pressure block is driven by the electric telescopic function to clamp and fix the top of the workpiece.

[0040] When welding P-shaped steel pipe workpiece 6, the workpiece is first placed on the laser welding fixture to position and clamp the workpiece, preventing the workpiece from shifting position during the welding process and affecting the welding accuracy. The limiting block 301 limits the side, the pneumatic rotary structure 4 limits the top, and the end of the workpiece is limited by the air blowing structure 5 to prevent excessive thermal deformation of the workpiece during welding, which would affect the flatness of the workpiece after welding.

[0041] The air blowing structure 5 includes a push block 501, an air pipe interface 502, an air port 503, and a cylinder 504. One side of the push block 501 is connected to the air pipe interface 502, and the other side is connected to the air port 503. Drive rods of the cylinder 504 are connected to both sides of the air pipe interface 502. The cylinder 504 is fixedly mounted on the base plate 101. The pneumatic adjustment function of the cylinder 504 can drive the push block 501 to perform linear position adjustment, so that after the workpiece is placed, the air port 503 is aligned with the workpiece port and fixed by the pushing action of the cylinder 504. During welding, cooling gas is introduced into the workpiece through the air pipe interface 502 and the air port 503 for cooling, reducing the temperature near the weld, minimizing thermal deformation of the workpiece, and improving the post-weld cooling efficiency. In a specific embodiment, an 8mm diameter air pipe is used, with a cooling gas pressure of 0.8MPa. A gas regulating valve is installed at the gas connection point, allowing the operator to adjust the pressure according to the actual welding conditions.

[0042] Incorporating oscillation into laser welding, the circular oscillation of the laser beam on the weld seam causes repeated remelting of parts of the weld, increasing the residence time of the molten metal in the weld pool. Simultaneously, the beam deflection increases the input heat per unit area, reduces the weld depth-to-width ratio, and facilitates the buoyancy of air bubbles, thus eliminating porosity. The weld metallographic morphology transforms from a sharp V-shape to a wide U-shape, ensuring penetration depth while increasing weld width and improving weld strength. Furthermore, the beam oscillation causes the aperture to oscillate accordingly, providing a stirring force to the weld pool, increasing convection and agitation, which is beneficial for eliminating porosity and reducing the impact of welding spatter on the steel pipe surface.

[0043] The laser welding method is as follows:

[0044] S1: Set process parameters such as laser power, robot running speed, and protective gas flow rate; set the oscillation width and frequency of the galvanometer welding head; place the high-strength steel pipe on the fixture; press it against the air blowing structure 5 and the side limiting block 301; start the pneumatic rotary structure 4 with one key; clamp the workpiece; fix the workpiece in the positioning position of the pneumatic rotary structure 4 and the limiting structure 3; and clamp the workpiece.

[0045] S2: Turn on the robot to teach the weld seam, use the CCD and laser red light to align the weld seam, adjust the defocus of the laser beam at the same time, clamp and start the welding robot signal, and the welding robot starts laser welding;

[0046] S3: Perform laser welding on a certain weld seam of the workpiece, and then continuously weld the next weld seam at intervals until all weld seams on the fixture are welded. After the laser welding is completed, the air blowing structure 5 on the welding fixture is activated to increase the cooling rate of the workpiece.

[0047] S4: During the workpiece welding process, the air blowing structure 5 dissipates heat from the workpiece, reducing the thermal deformation of the workpiece caused by laser welding. After the workpiece cools down, the pneumatic rotary structure 4 is released, and the workpiece is unloaded.

[0048] The laser welding method uses a six-axis robot as the motion unit, with a maximum processing area of ​​2m and a maximum load of 20kg, which meets the requirements for laser welding.

[0049] The laser welding head is equipped with a coaxial vision CCD and a linear red light to facilitate the correction of the welding focus. Before laser welding, the weld is taught and pre-traced along the center line of the weld, ensuring that the error between the teaching point and the center line of the weld does not exceed 0.5mm. The laser output power range is 0~6KW. The laser welding head uses a galvanometer with a coaxial vision CCD, and the laser welding speed is 1m / min~5m / min.

[0050] The galvanometer can be oscillated in circular, linear, figure-eight, or infinite directions. The galvanometer oscillation parameters are set to an amplitude of 0.8mm and a frequency of 0.4mm. The weld seam is taught using laser red light, auxiliary linear red light, and a coaxial vision CCD, while ensuring the laser focus position is maintained. The weld seam deviation is <0.5mm. After teaching, the weld seam trajectory is simulated once. The laser power is set to 3200W, the robot welding speed to 2.4m / min, and the focus position to 0m. After parameter settings, the robot performs welding. Before laser emission, protective gas and lateral air curtains are pre-blown. After laser welding, cooling gas is blown into the steel pipe to lower its temperature, improving cooling efficiency and reducing cooling time. Once the steel pipe is completely cooled, the fixture is started with a single button, and the material is manually unloaded to complete the repair welding. After welding, the steel pipe is cut, ground, and etched. Metallographic analysis is performed, and the weld depth and width are measured under a metallographic microscope. The weld depth is >1mm, and the weld width is >1.3mm. The weld surface exhibits minimal spatter and thermal deformation.

[0051] To facilitate understanding of the above technical solutions of the present invention, the working principle or operation method of the present invention in actual process will be described in detail below.

[0052] In summary, with the aid of the above-mentioned technical solution of the present invention, the laser welding fixture is adapted to a specific workpiece, namely a P-shaped steel pipe workpiece 6, with a pipe length of 1.2m-1.5m. The entire welding fixture is placed on the ground, and a limiting groove 2 is provided on the base plate 101, with a sliding connection of the limiting block 301. According to the length and width of the steel pipe, the relative positions of the limiting structure 3 and the air blowing structure 5 are adjusted to place them in the middle position of the workpiece. The limiting structure 3 rotates the threaded rod 307 by adjusting the rotating head 309. Since one end of the threaded sleeve 308 is fixedly installed on one side of the base plate 101, the relative position of the threaded sleeve 308 and the threaded rod 307 is adjusted. Furthermore, by adjusting the position of the adjusting block 304 and the connecting rod 303, the positions of the sliding block 302 and the limiting block 301 are adjusted, so that the limiting block 301 can clamp and fix the workpiece from the side. When welding the P-shaped steel pipe workpiece 6, the workpiece is first placed on the laser welding fixture to position and clamp the workpiece, preventing the workpiece from shifting position during the welding process and affecting the welding accuracy. The limiting block 301 limits the side, the pneumatic rotary structure 4 limits the top, and the end of the workpiece is limited by the air blowing structure 5 to prevent excessive thermal deformation of the workpiece during welding, which would affect the flatness of the workpiece after welding. The pneumatic adjustment function of the cylinder 504... The cylinder 504 can drive the push block 501 to adjust its linear position, so that after the workpiece is placed, the cylinder 504 pushes the air port 503 to align with the workpiece end for docking and fixation. During the welding process, cooling gas is introduced into the workpiece through the air pipe interface 502 and the air port 503 for cooling, reducing the temperature near the weld, minimizing thermal deformation of the workpiece, and improving the cooling efficiency after welding. In a specific embodiment, an 8mm diameter air pipe is used, the cooling gas pressure is 0.8MPa, and a gas regulating valve is installed. The operator can adjust the pressure according to the actual welding situation. Oscillation is added to the laser welding process. The circular oscillation of the laser beam on the weld seam causes repeated remelting of some weld seams, increasing the residence time of the molten metal in the weld pool. At the same time, the deflection of the beam increases the input heat per unit area, reduces the depth-to-width ratio of the weld seam, and facilitates the buoyancy of air bubbles, thereby eliminating porosity. The weld metallographic morphology changes from a pointed V-shape to a wide U-shape, ensuring the penetration depth while increasing the weld width and improving the welding strength. On the other hand, the oscillation of the beam causes the aperture to oscillate accordingly, which in turn provides a stirring force to the weld pool, increasing convection and stirring of the weld pool, which is beneficial for eliminating porosity and can reduce the impact of welding spatter on the surface of the steel pipe.

[0053] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser welding method, applied to a laser welding fixture, characterized in that... : The laser welding fixture includes: a mounting structure (1), a limiting groove (2), multiple limiting structures (3), a pneumatic rotary structure (4), and an air blowing structure (5). The mounting structure (1) includes a base plate (101), on which a limiting groove (2) is formed. The limiting groove (2) is connected to the limiting structure (3). The top of the base plate (101) is connected to the pneumatic rotary structure (4). A P-shaped steel pipe workpiece (6) is placed on one side of the pneumatic rotary structure (4). The two ends of the P-shaped steel pipe workpiece (6) are connected to the air blowing structure (5). The limiting structure (3) includes multiple limiting blocks (301), sliding blocks (302), and connecting rods. (303) and adjusting block (304); the bottom end of the limiting block (301) is fixedly connected to a sliding block (302), the sliding block (302) is slidably connected in the limiting groove (2), the sliding block (302) is fixedly connected to a connecting rod (303), the end of the connecting rod (303) is fixedly connected to an adjusting block (304), the limiting block (301) is used to clamp and fix the P-type steel pipe workpiece (6) from the side; the air blowing structure (5) includes a pushing block (501) and an air port (503), the air port (503) is used to dock with the port of the P-type steel pipe workpiece (6) and fix the port of the P-type steel pipe workpiece (6); The method includes the following steps: S1: Set the laser output power, welding robot running speed, protective gas flow rate, galvanometer welding head swing width and frequency, place the P-type steel pipe workpiece (6) on the fixture, close the air blowing structure (5) and the side limiting block (301), start the pneumatic rotary structure (4) with one key, clamp the P-type steel pipe workpiece (6), fix the P-type steel pipe workpiece (6) in the positioning position of the pneumatic rotary structure (4) and the limiting structure, and clamp the P-type steel pipe workpiece (6); S2: Turn on the welding robot to teach the weld seam. Use the coaxial vision CCD and the laser red light to align the weld seam respectively. At the same time, adjust the defocus of the laser beam. After the P-type steel pipe workpiece (6) is clamped, start the welding robot signal and the welding robot starts laser welding. S3: Laser welding is performed on a certain weld of the P-type steel pipe workpiece (6), and then the next weld is continuously welded at intervals until all welds on the fixture are completed. After the laser welding is completed, the air blowing structure (5) is activated to increase the cooling speed of the P-type steel pipe workpiece (6). S4: During the welding process of P-type steel pipe workpiece (6), the air blowing structure (5) is used to dissipate heat from the P-type steel pipe workpiece (6) to reduce the thermal deformation of the P-type steel pipe workpiece (6) caused by laser welding. After the P-type steel pipe workpiece (6) cools down, the pneumatic rotating structure (4) is released and the P-type steel pipe workpiece (6) is unloaded.

2. The laser welding method according to claim 1, characterized in that, The limiting structure (3) also includes a sleeve rod (305), a spring (306), a threaded rod (307), a threaded sleeve (308), and a rotating head (309); one end of the sleeve rod (305) is fixedly connected to one side of the adjusting block (304), the spring (306) is sleeved on the sleeve rod (305), a threaded rod (307) is provided on one side of the sleeve rod (305), the threaded rod (307) is threadedly connected to the threaded sleeve (308), one end of the threaded sleeve (308) is fixedly connected to one side of the base plate (101), and the other end of the threaded rod (307) is fixedly connected to the rotating head (309).

3. The laser welding method according to claim 2, characterized in that, The pneumatic rotary structure (4) includes a motor (401), a rotating shaft (402), a connecting rod (403), and a telescopic rod (404). The driving end of the motor (401) is connected to the rotating shaft (402).

4. The laser welding method according to claim 3, characterized in that, A connecting rod (403) is fixedly connected to the rotating shaft (402). A telescopic rod (404) is connected to the bottom end of one end of the connecting rod (403). The driving end pressure block of the telescopic rod (404) of the pneumatic rotary structure (4) is provided with a rubber pad.

5. The laser welding method according to claim 4, characterized in that, The air blowing structure (5) also includes an air pipe interface (502) and a cylinder (504). One side of the push block (501) is connected to the air pipe interface (502), and the other side of the push block (501) is connected to an air port (503). The two sides of the air pipe interface (502) are connected to the drive rods of the cylinder (504), and the cylinder (504) is fixedly installed on the base plate (101).

6. The laser welding method according to claim 1, characterized in that, The galvanometer welding head is equipped with a coaxial vision CCD and a linear red light to facilitate the correction of the welding focus. Before laser welding, the weld is taught and pre-traced along the center line of the weld, ensuring that the error between the teaching point and the center line of the weld does not exceed 0.5mm. The output power of the laser is in the range of 0~6KW. The galvanometer welding head is a galvanometer lens with a coaxial vision CCD, and the laser welding speed is 1m / min~5m / min.

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