Pipeline welding device for laser welding and welding method

Abstract

The invention relates to a pipeline welding device for laser welding and a welding method.The pipeline welding device comprises a first fixing plate, three air cylinders are arranged on the first fixing plate, the output ends of the air cylinders are jointly provided with a supporting plate, a rack plate is rotationally arranged in the supporting plate, two supporting plates are arranged on the rack plate, and welding arms are installed on the supporting plates correspondingly; under the condition that the air cylinder pushes the pushing supporting plate, the welding arm is adjusted to the gap distance between the two pipelines so as to perform adaptive adjustment; when a joint between two pipelines needs to be welded, the air cylinder can push the supporting plate, so that the welding arm can be gradually close to a gap between the two pipelines, in the process, the welding arm can accurately adjust the gap distance between the two pipelines through the synergistic effect of the rack plate and the supporting plate, and therefore adaptive adjustment is achieved; the welding precision and efficiency are improved, and the whole welding process is more flexible and controllable.

Description

Technical Field

[0001] The invention belongs to the technical field of laser welding, and relates to a pipeline welding device and a welding method for laser welding. Background Art

[0002] The automatic welding of existing pipelines usually adopts the method of aligning and fixing two sections of pipelines to be welded with a certain gap, and then using a welding robot to perform filler welding on the gap between the two pipelines.

[0003] For example, a Chinese patent with application number: 2023117943435 discloses a ring welding robot for pipeline welding, including a strip plate that can be bent into a ring, a track for a mobile unit to slide is arranged at intervals on one side of the strip plate, and a welding arm is installed on the mobile unit. The present invention overcomes the shortcomings of the prior art, has a reasonable design and a compact structure, connects the strip plates end to end, so that the support column is against the outer wall of the circular tube, at this time the strip plate and the track are in a circular ring shape, and then the welding arm is driven by the mobile unit to perform circular welding on the outer wall of the circular tube, and the strip plate is bent in the reverse direction, and the strip plate is connected end to end, and the support column is supported outward to the inner wall of the circular tube, so that the strip plate and the track are in a circular ring shape; although the technical solution can realize circular welding in a small space, in the technical solution, once the strip plate is fixed on the outer wall of the pipeline, the gap distance between the welding arm and the two pipelines cannot be adjusted, thereby causing the limitation of the technical solution. Summary of the invention

[0004] The object of the present invention is to provide a pipeline welding device and a welding method for laser welding, which can solve the problems raised by the background technology.

[0005] According to the technical solution provided by the present invention, a laser welding device for pipes comprises a first fixed plate, three cylinders are arranged on the first fixed plate, a support plate is arranged at the output ends of the cylinders, a rack plate is arranged inside the support plate for rotation, two support plates are arranged on the rack plate, welding arms are respectively installed on the support plates, and the welding arms are adjusted to the gap distance between the two pipes to make adaptive adjustment when the cylinders push the support plates;

[0006] A motor is installed on the support plate, and a gear meshing with the rack plate is sleeved on the output shaft of the motor, and driven by the gear, the rack plate is driven to move in the support plate; a group of tooth connecting plates are respectively provided at both ends of the rack plate, and each tooth connecting plate is respectively provided with teeth, and the tooth connecting plates on each group are hinged in turn and meshed with the gear.

[0007] Preferably, the support plate is provided with a first groove and a second groove, the first groove is in an L-shaped structure, and the first groove is communicated with the second groove; the rack plate and each tooth connecting plate are provided with a clamping block, and the clamping block is adapted to the first groove.

[0008] Preferably, a second fixing plate is provided below the first fixing plate, and two first bolts are provided between the second fixing plate and the first fixing plate. The two first bolts cooperate with each other to fix and clamp the second fixing plate and the first fixing plate to the outer wall of the pipeline.

[0009] Preferably, connecting plates are respectively provided at the extending parts at both ends of the second fixing plate, a fourth fixing plate is commonly provided on the two connecting plates, a third fixing plate is provided above the fourth fixing plate, two second bolts are provided between the third fixing plate and the fourth fixing plate, the two second bolts cooperate with each other to fix and clamp the third fixing plate and the fourth fixing plate on the outer wall of the pipe, and cooperate with the use of the second fixing plate and the first fixing plate to keep the two sections of the pipe coaxial.

[0010] Preferably, the first fixing plate, the second fixing plate, the third fixing plate and the fourth fixing plate are all arc-shaped to cooperate with the pipeline, and the opening ends of the four respectively extend outward to form extension parts, and the extension parts are respectively provided with threaded holes to facilitate the use with the first bolt and the second bolt.

[0011] Preferably, reinforcing rods are respectively provided at the lower ends of the connecting plates, and both ends of the reinforcing rods extend to the extension parts of the second fixing plate and the fourth fixing plate respectively to increase the stability and firmness of the connecting plates.

[0012] Preferably, a slot and two first threaded holes are provided at the bottom of one group of the tooth connecting plates, and an insert plate adapted to the slot and two second threaded holes are provided at the bottom of another group of the tooth connecting plates, and third bolts are respectively screwed to the second threaded holes. When the insert plate is inserted into the slot, the threaded end of the third bolt is screwed to the first threaded hole, so that the tooth connecting plate and the rack plate form a circle and surround the outer wall of the pipe.

[0013] Preferably, three first rolling balls are embedded in the inner wall of the rack plate, and second rolling balls are respectively embedded in the two tooth connecting plates on each group, and the second rolling balls and the first rolling balls are in contact with the outer wall of the pipe to reduce the friction between the tooth connecting plate, the rack plate and the outer wall of the pipe, so as to improve the smoothness of the rotation of the tooth connecting plate and the rack plate on the outer wall of the pipe.

[0014] Preferably, a grinding rod is provided on the rack plate, and a fourth bolt is screwed on the central axis of the grinding rod. By rotating the fourth bolt, the grinding rod is fixed to the rack plate to form a fixed connection between the grinding rod and the rack plate. By rotating the fourth bolt, the grinding rod can be removed and replaced.

[0015] A pipeline welding method for laser welding comprises the following steps:

[0016] S1. First, put the first fixing plate on the outer wall of the pipe, and then put the fourth fixing plate on the outer wall of the pipe, and align the second fixing plate and the third fixing plate with the first fixing plate and the fourth fixing plate in turn through the first bolt and the second bolt, and fix them on the outer wall of the pipe. At this time, the gap between the two pipes is located in the middle of the first fixing plate and the third fixing plate.

[0017] S2. After the fixation is completed, the first rolling ball and the second rolling ball contact the outer wall of the pipe, and under the push of the cylinder, the support plate is pushed forward so that the two welding arms are located in the gap between the two pipes.

[0018] S3. At this time, the plug plate is matched with the slot, and the third bolt is rotated, and the third bolt is screwed with the first threaded hole and the second threaded hole, so that the tooth connecting plate and the rack plate form a circle and are attached to the outer wall of the pipe.

[0019] S4. Restart the motor. During the operation of the motor, the gears are driven to rotate. As the gears rotate, the rack plate and the tooth connecting plate rotate around the outer wall of the pipe. At the same time, the grinding rod also rotates with the rack plate and grinds the places that need to be welded to ensure the firmness of the welding.

[0020] S5. After grinding, the welding arm is powered on. The welding arm welds the gap between the two pipes as the rack plate rotates. During the welding process, the grinding rod grinds the oxide layer left after welding. After welding, the grinding rod is driven by the rack plate to circle around the oxide layer after welding and grind off the oxide layer to ensure the durability of the welding point.

[0021] The positive effects of this application are:

[0022] The embodiments of the present invention provide a pipeline welding device and a welding method for laser welding, which have the following advantages:

[0023] 1. When welding the joint between two pipes, the cylinder will push the support plate so that the welding arm can gradually approach the gap between the two pipes. In this process, the synergistic effect of the rack plate and the support plate enables the welding arm to accurately adjust to the gap distance between the two pipes, thereby achieving adaptive adjustment, which not only improves the welding accuracy and efficiency, but also makes the entire welding process more flexible and controllable.

[0024] 2. The connecting plates act as a bridge, connecting the second fixing plate with the subsequent fixing structure, and they also ensure the stability and firmness of the entire structure; at the same time, the third fixing plate and the fourth fixing plate are fixedly clamped on the outer wall of the pipe, and in conjunction with the second fixing plate and the first fixing plate, the entire fixation forms a complete, three-dimensional fixing system, which not only ensures the coaxiality of the two sections of the pipe at the connection, that is, their center lines perfectly coincide, thereby avoiding problems such as fluid leakage or pipe damage caused by axis deviation.

[0025] 3. The setting of the grinding stick can be used to treat the surface of the pipe that needs to be welded. It not only removes the dirt and oxides on the surface of the pipe, but also increases the roughness of the welding surface, thereby greatly improving the firmness and reliability of the welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a perspective view of the present invention.

[0027] Figure 2 It is a schematic diagram of the connection between the rack plate and the tooth connecting plate of the present invention.

[0028] Figure 3 It is a schematic diagram of a cutaway portion of a tooth connecting plate of the present invention.

[0029] Figure 4 It is a schematic diagram of the connection between the plugboard and the slot of the present invention.

[0030] Figure 5 It is a schematic cross-sectional view of a support plate of the present invention.

[0031] Figure 6 It is a top view of the present invention.

[0032] Figure 7 It is a front view of the present invention.

[0033] Figure 8 It is a side view of the present invention.

[0034] Fig. 9 It is a schematic cross-sectional view of the present invention.

[0035] In the figure: a first fixing plate 1; a second fixing plate 11; a first bolt 12; a connecting plate 13; a third fixing plate 14; a fourth fixing plate 15; a second bolt 16; a reinforcing rod 17; a cylinder 2; a support plate 22; a first groove 221; a second groove 222; a rack plate 23; a motor 24; a gear 25; a support plate 26; a welding arm 27; a tooth connecting plate 3; a tooth 31; a slot 32; a first threaded hole 33; a plug plate 34; a second threaded hole 35; a third bolt 36; a grinding stick 4; a fourth bolt 41; a first rolling ball 42; a second rolling ball 43; a block 5. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0037] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0038] like Figure 1-9 As shown, the present invention is a pipeline welding device for laser welding, comprising a first fixed plate 1, on which three cylinders 2 are arranged, and output ends of the cylinders 2 are commonly provided with a support plate 22, and a rack plate 23 is provided for rotation inside the support plate 22, and two support plates 26 are provided on the rack plate 23, and welding arms 27 are respectively installed on the support plates 26, and when the cylinders 2 push the support plate 22, the welding arms 27 are adjusted to the gap distance between the two pipelines to make adaptive adjustments;

[0039] The first fixing plate 1 is a basic supporting structure of the entire welding device and is firmly installed at the required working position. The three cylinders 2 are arranged in a certain layout to ensure that they can work together to provide a stable driving force;

[0040] When it is necessary to weld the joint between two pipes, the cylinder 2 will push the support plate 22 so that the welding arm 27 can gradually approach the gap between the two pipes. In this process, the coordinated action of the rack plate 23 and the support plate 26 enables the welding arm 27 to accurately adjust to the gap distance between the two pipes, thereby achieving adaptive adjustment, which not only improves the welding accuracy and efficiency, but also makes the entire welding process more flexible and controllable.

[0041] The support plate 22 is provided with a motor 24, and the output shaft of the motor 24 is sleeved with a gear 25 meshing with the rack plate 23, and driven by the gear 25, the rack plate 23 is driven to move in the support plate 22; a group of tooth connecting plates 3 are respectively provided at both ends of the rack plate 23, and each tooth connecting plate 3 is respectively provided with teeth 31, and the tooth connecting plates 3 on each group are hinged in sequence and meshed with the gear 25;

[0042] The support plate 22 is provided with a first groove 221 and a second groove 222, the first groove 221 is in an L-shaped structure, and the first groove 221 is communicated with the second groove 222; the rack plate 23 and each tooth connecting plate 3 are provided with a clamping block 5, and the clamping block 5 is adapted to the first groove 221;

[0043] When the motor 24 rotates, the gear 25 will first mesh with the rack plate 23, so that the rack 23 slides in the second groove 221, and at the same time drives the block 5 on the rack plate 23 to move in the first groove 221. When the teeth 31 mesh with the gear 23, the tooth connecting plate 3 slides in the second groove 221, and the block 5 on the tooth connecting plate 3 moves in the first groove 221. The matching of the block 5 and the first groove 221 maintains the stability of the rack plate 23 and the tooth connecting plate 3 during the rotation process, thereby improving the stability of the welding arm 4 during welding.

[0044] The rack plate 23 and the support plate 22 are both arc-shaped, and the support plate 22 extends from both ends of the rack plate 23 to form a hinge with the tooth connecting plate 3; the motor 22 is installed at the center of the support plate 21, so that when the motor 22 rotates forward and reverse, the movement trajectory of the welding arm 27 is consistent.

[0045] Preferably, a second fixing plate 11 is provided below the first fixing plate 1, and two first bolts 12 are provided between the second fixing plate 11 and the first fixing plate 1. The two first bolts 12 cooperate with each other to fix and clamp the second fixing plate 11 and the first fixing plate 1 to the outer wall of the pipeline.

[0046] Preferably, the second fixing plate 11 is provided with connecting plates 13 at the two end extensions, and the two connecting plates 13 are provided with a fourth fixing plate 15. A third fixing plate 14 is provided above the fourth fixing plate 15, and two second bolts 16 are provided between the third fixing plate 14 and the fourth fixing plate 15. The two second bolts 16 cooperate with each other to fix and clamp the third fixing plate 14 and the fourth fixing plate 15 on the outer wall of the pipeline, and cooperate with the second fixing plate 11 and the first fixing plate 1, so that the two sections of the pipeline are kept on the same axis;

[0047] The connecting plate 13 acts as a bridge, connecting the second fixing plate 11 with the subsequent fixing structure, and they also ensure the stability and firmness of the entire structure; at the same time, the third fixing plate 14 and the fourth fixing plate 15 are fixedly clamped on the outer wall of the pipeline, and cooperate with the second fixing plate 11 and the first fixing plate 1, the entire fixation forms a complete, three-dimensional fixing system, this system not only ensures the coaxiality of the two sections of the pipeline at the connection, that is, their center lines perfectly coincide, thereby avoiding problems such as fluid leakage or pipeline damage caused by axis deviation.

[0048] Preferably, the first fixing plate 1, the second fixing plate 11, the third fixing plate 14, and the fourth fixing plate 15 are all arc-shaped to cooperate with the pipeline, and the opening ends of the four extend outward to form extension parts, which are respectively provided with threaded holes to facilitate the use with the first bolt 12 and the second bolt 16.

[0049] Preferably, the lower ends of the connecting plates 13 are provided with reinforcing rods 17 , and both ends of the reinforcing rods 17 extend to the extended portions of the second fixing plate 11 and the fourth fixing plate 15 , respectively, so as to increase the stability and firmness of the connecting plates 13 .

[0050] Preferably, a slot 32 and two first threaded holes 33 are provided at the bottom of one group of the tooth connecting plates 3, and a plug plate 34 adapted to the slot 32 and two second threaded holes 35 are provided at the bottom of another group of the tooth connecting plates 3, and third bolts 36 are respectively screwed on the second threaded holes 35. When the plug plate 34 is inserted into the slot 32, the threaded end of the third bolt 36 is screwed with the first threaded hole 33, so that the tooth connecting plate 3 and the rack plate 23 form a circle and surround the outer wall of the pipe.

[0051] Preferably, three first rolling balls 42 are embedded in the inner wall of the rack plate 23, and second rolling balls 43 are respectively embedded in the two tooth connecting plates 3 on each group of tooth connecting plates 3. The second rolling balls 43 and the first rolling balls 42 are in contact with the outer wall of the pipe to reduce the friction between the tooth connecting plate 3, the rack plate 23 and the outer wall of the pipe, so as to improve the smoothness of the rotation of the tooth connecting plate 3 and the rack plate 23 on the outer wall of the pipe.

[0052] The first rolling ball 42 is not only hard and wear-resistant, but also has a smooth surface, which can effectively reduce the friction coefficient when in contact with the outer wall of the pipe, thereby reducing the driving force required for the rack plate 23 to rotate on the outer wall of the pipe, reducing wear and extending the service life;

[0053] At the same time, the second rolling ball 43 and the first rolling ball 42 complement each other in function and act together on the outer wall of the pipe, further reducing the friction between the tooth connecting plate 3 and the outer wall of the pipe, so that the tooth connecting plate 3 can be smoother and more fluent when rotating around the outer wall of the pipe with the rack plate 23, reducing the generation of jamming and resistance;

[0054] The embedding position and number of the first rolling ball 42 and the second rolling ball 43 not only ensure sufficient contact with the outer wall of the pipe, realize effective support and guidance for the rotation of the tooth connecting plate 3 and the rack plate 23, but also improve the stability and reliability of the entire structure, and greatly enhance the flexibility and smoothness of the rotation of the tooth connecting plate 3 and the rack plate 23 on the outer wall of the pipe.

[0055] Preferably, a grinding rod 4 is provided on the rack plate 23, and a fourth bolt 41 is screwed on the central axis of the grinding rod 4. By rotating the fourth bolt 41, the grinding rod 4 is fixed to the rack plate 23 to form a fixed connection between the grinding rod 4 and the rack plate 23. By rotating the fourth bolt 41, the grinding rod 4 can be removed and replaced.

[0056] The fourth bolt 41 realizes the threaded connection between the grinding rod 4 and the rack plate 23, which not only makes the installation and removal of the grinding rod 4 extremely simple, but also ensures the firm connection between the grinding rod 4 and the rack plate 23 through the pre-tightening force generated by the fourth bolt 41;

[0057] In actual operation, when the sanding rod 4 needs to be installed, it is only necessary to align the central axis of the sanding rod 4 with the reserved hole on the rack plate 23, and then rotate the fourth bolt 41 so that it gradually penetrates along the threaded section of the central axis of the sanding rod 4 until it fits tightly with the other side of the rack plate 23. In this way, the sanding rod 4 is firmly fixed on the rack plate 23, forming a stable overall structure.

[0058] The setting of the grinding stick 4 can be used to treat the surface of the pipe to be welded, which not only removes dirt and oxides on the surface of the pipe, but also increases the roughness of the welding surface, thereby greatly improving the firmness and reliability of the welding;

[0059] At this time, the welding gun on the welding arm 27 quickly melts the welding rod at high temperature and firmly welds the two pipes together. During this process, the grinding rod 4 does not stop working and continues to grind the oxide layer left after welding to ensure the neatness and smoothness of the welding point.

[0060] After welding is completed, the system does not stop running immediately. On the contrary, the grinding rod 4, driven by the rack plate 23, continues to circle around the oxide layer after welding to completely remove all oxide layers and impurities generated during the welding process and ensure the durability of the welding point. Through this comprehensive grinding treatment, the strength and toughness of the welding point are further improved, thereby ensuring the stability and safety of the entire pipeline system.

[0061] The steps include:

[0062] S1. First, put the first fixing plate 1 on the outer wall of the pipe, and then put the fourth fixing plate 15 on the outer wall of the pipe, and align the second fixing plate 11 and the third fixing plate 14 with the first fixing plate 1 and the fourth fixing plate 15 in turn through the first bolt 12 and the second bolt 16, and fix them on the outer wall of the pipe. At this time, the gap between the two pipes is located in the middle of the first fixing plate 1 and the third fixing plate 14.

[0063] S2. After the fixation is completed, the first rolling ball 42 and the second rolling ball 43 contact the outer wall of the pipe, and under the push of the cylinder 2, push the support plate 22 forward so that the two welding arms 27 are located in the gap between the two pipes.

[0064] S3. At this time, the plug plate 34 is matched with the slot 32, and the third bolt 36 is rotated. The third bolt 36 is screwed with the first threaded hole 33 and the second threaded hole 35, so that the tooth connecting plate 3 and the rack plate 23 form a circle and are attached to the outer wall of the pipe.

[0065] S4. Restart the motor 24. During operation, the motor 24 drives the gear 25 to rotate. As the gear 25 rotates, the rack plate 23 and the tooth connecting plate 3 rotate around the outer wall of the pipe. At the same time, the grinding rod 4 also rotates with the rack plate 23 and grinds the places that need to be welded to ensure the firmness of the welding.

[0066] S5. After the grinding is completed, the welding arm 27 is energized, and the welding arm 27 welds the gap between the two pipes as the rack plate 23 rotates. During the welding process, the grinding rod 4 grinds the oxide layer left after welding. After the welding is completed, the grinding rod 4 is driven by the rack plate 23 to rotate around the oxide layer after welding, and grinds off the oxide layer to ensure the durability of the welding point.

[0067] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A pipeline welding device for laser welding, characterized in that: The invention comprises a first fixed plate (1), three cylinders (2) are arranged on the first fixed plate (1), a support plate (22) is commonly arranged at the output ends of the cylinders (2), a rack plate (23) is rotatably arranged inside the support plate (22), two support plates (26) are arranged on the rack plate (23), welding arms (27) are respectively installed on the support plates (26), and when the cylinders (2) push the support plate (22), the welding arms (27) are adjusted to the gap distance between the two pipes to make adaptive adjustment; The support plate (22) is provided with a motor (24), the output shaft of the motor (24) is sleeved with a gear (25) meshing with the rack plate (23), and driven by the gear (25), the rack plate (23) is driven to move in the support plate (22); a group of tooth connecting plates (3) are respectively provided at both ends of the rack plate (23), each tooth connecting plate (3) is respectively provided with teeth (31), and the tooth connecting plates (3) on each group are hinged in sequence and meshed with the gear (25).

2. A laser welding device for pipe welding according to claim 1, characterized in that: The support plate (22) is provided with a first groove (221) and a second groove (222); the first groove (221) is in an L-shaped structure, and the first groove (221) is communicated with the second groove (222); the rack plate (23) and each tooth connecting plate (3) are provided with a clamping block (5), and the clamping block (5) is adapted to the first groove (221).

3. A pipeline welding device for laser welding as claimed in claim 1, characterized in that: A second fixing plate (11) is provided below the first fixing plate (1), and two first bolts (12) are provided between the second fixing plate (11) and the first fixing plate (1). The two first bolts (12) cooperate with each other to fix and clamp the second fixing plate (11) and the first fixing plate (1) on the outer wall of the pipeline.

4. A pipeline welding device for laser welding as claimed in claim 3, characterized in that: The second fixing plate (11) is provided with connecting plates (13) at the two end extensions, and a fourth fixing plate (15) is provided on the two connecting plates (13). A third fixing plate (14) is provided above the fourth fixing plate (15). Two second bolts (16) are provided between the third fixing plate (14) and the fourth fixing plate (15). The two second bolts (16) cooperate with each other to fix and clamp the third fixing plate (14) and the fourth fixing plate (15) on the outer wall of the pipeline, and cooperate with the second fixing plate (11) and the first fixing plate (1) to keep the two sections of the pipeline coaxial.

5. A laser welding pipe welding device as claimed in claim 4, characterized in that: The first fixing plate (1), the second fixing plate (11), the third fixing plate (14) and the fourth fixing plate (15) are all arc-shaped so as to be used in conjunction with the pipeline. At the same time, the opening ends of the four plates extend outwards to form extension parts, and the extension parts are respectively provided with threaded holes so as to be used in conjunction with the first bolts (12) and the second bolts (16).

6. A laser welding pipe welding device as claimed in claim 5, characterized in that: The lower ends of the connecting plates (13) are respectively provided with reinforcing rods (17), and the two ends of the reinforcing rods (17) respectively extend to the extension parts of the second fixing plate (11) and the fourth fixing plate (15) to increase the stability and firmness of the connecting plates (13).

7. The laser welding device for pipe welding according to claim 1, characterized in that: The lower end of one group of tooth connecting plates (3) is provided with a slot (32) and two first threaded holes (33), and the lower end of another group of tooth connecting plates (3) is provided with a plug plate (34) adapted to the slot (32) and provided with two second threaded holes (35), and third bolts (36) are respectively screwed on the second threaded holes (35). When the plug plate (34) is inserted into the slot (32), the threaded ends of the third bolts (36) are screwed on the first threaded holes (33), so that the tooth connecting plates (3) and the rack plate (23) form a circle and surround the outer wall of the pipe.

8. A pipeline welding device for laser welding as claimed in claim 7, characterized in that: The inner wall of the rack plate (23) is embedded with three first rolling balls (42), and the two tooth connecting plates (3) on each group of tooth connecting plates (3) are respectively embedded with second rolling balls (43), and the second rolling balls (43) and the first rolling balls (42) are in contact with the outer wall of the pipe to reduce the friction between the tooth connecting plate (3), the rack plate (23) and the outer wall of the pipe, so as to improve the smoothness of the tooth connecting plate (3) and the rack plate (23) rotating on the outer wall of the pipe.

9. The laser welding device for pipe welding according to claim 1, characterized in that: The rack plate (23) is provided with a grinding rod (4), and a fourth bolt (41) is screwed on the central axis of the grinding rod (4). When the fourth bolt (41) is rotated, the grinding rod (4) is fixed to the rack plate (23) to form a fixed connection between the grinding rod (4) and the rack plate (23). When the fourth bolt (41) is rotated, the grinding rod (4) can be removed and replaced.

10. A pipeline welding method for laser welding, using a pipeline welding device for laser welding according to any one of claims 1 to 9, characterized in that: The steps include: S1. First, the first fixing plate (1) is put on the outer wall of the pipe, and then the fourth fixing plate (15) is also put on the outer wall of the pipe, and the second fixing plate (11) and the third fixing plate (14) are aligned with the first fixing plate (1) and the fourth fixing plate (15) in turn through the first bolt (12) and the second bolt (16), and fixed on the outer wall of the pipe. At this time, the gap between the two pipes is located in the middle of the first fixing plate (1) and the third fixing plate (14). S2. After the fixing is completed, the first rolling ball (42) and the second rolling ball (43) contact the outer wall of the pipe, and under the push of the cylinder (2), the support plate (22) is pushed forward so that the two welding arms (27) are located in the gap between the two pipes. S3. At this time, the plug plate (34) is matched with the slot (32), and the third bolt (36) is rotated. The third bolt (36) is screwed with the first threaded hole (33) and the second threaded hole (35), so that the tooth connecting plate (3) and the rack plate (23) form a circle and are attached to the outer wall of the pipe. S4. The motor (24) is restarted. During the operation of the motor (24), the gear (25) is driven to rotate. As the gear (25) rotates, the rack plate (23) and the tooth connecting plate (3) rotate around the outer wall of the pipe. At the same time, the grinding rod (4) also rotates with the rack plate (23) and grinds the places that need to be welded to ensure the firmness of the welding. S5. After the grinding is completed, the welding arm (27) is energized, and the welding arm (27) welds the gap between the two pipes as the rack plate (23) rotates. During the welding process, the grinding rod (4) grinds the oxide layer left after welding. After the welding is completed, the grinding rod (4) is driven by the rack plate (23) to rotate around the oxide layer after welding and grind off the oxide layer to ensure the durability of the welding point.

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