Thin-wall metal pipeline welding equipment and welding method

Abstract

The invention relates to the technical field of welding equipment, in particular to thin-wall metal pipeline welding equipment and a welding method. The butt joint ring is located between the two metal pipes and used for conducting welding connection on the two metal pipes, the driving unit is used for providing rotation power for the butt joint ring, the two pushing units are used for providing pushing force for the two metal pipes respectively, and the pushing force provided by the pushing units for the metal pipes is in the axis direction of the metal pipes. The butt-joint ring and the two metal pipes can be welded and connected at the same time in the mode that the butt-joint ring and the two metal pipes conduct relative friction movement at the same time, so that connection of the two metal pipes is achieved, meanwhile, the conical surfaces on the two end faces of the butt-joint ring are used for flaring the end faces of the two metal pipes, and the contact area of the metal pipes and the butt-joint ring can be increased. Therefore, the welding strength is improved; the welding mode does not have welding defects such as weld penetration and damage, and the welding firmness is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding equipment, and particularly relates to a welding equipment and a welding method for thin-walled metal pipes. Background Art

[0002] With the rapid development of modern industry towards lightweight and high-precision directions, thin-walled metal pipes are increasingly widely used in the fields of energy transportation, aerospace, automotive manufacturing, precision instruments, etc. due to their advantages such as light weight, high material utilization rate, and compact structure. For example, high-sealing thin-walled pipes are required for hydrogen energy storage and transportation systems, strict requirements for high temperature resistance and fatigue resistance are put forward for spacecraft propulsion pipelines, and the precise forming and connection of ultra-thin pipes are relied on for microelectronic radiators.

[0003] During the processing or assembly of thin-walled metal pipes, butt welding of metal pipes is a common processing method. The traditional welding method is to butt two metal pipes together and then weld the butt position together by means of laser welding, electric welding, etc. However, due to the small wall thickness of the metal pipes, the traditional welding method is prone to welding defects such as burn-through and breakage, and the connection area of the two metal pipes is small, resulting in low welding strength. Summary of the Invention

[0004] In view of the above technical problems, the present invention provides a welding equipment and a welding method for thin-walled metal pipes, and the specific technical solutions adopted are as follows: According to a first aspect of the present invention, there is provided a welding equipment for thin-walled metal pipes, including a docking ring located between two metal pipes and used for welding and connecting the two metal pipes, a driving unit for providing rotational power for the docking ring, and two pushing units for respectively providing driving forces for the two metal pipes, wherein the driving force provided by the pushing unit for the metal pipe is along the axial direction of the metal pipe; Both end faces of the docking ring along its own axis direction are set as conical surfaces, and the conical surfaces are used for extruding the end parts of the metal pipes and deforming them by flaring.

[0005] In some embodiments of the present invention, both end faces of the docking ring along its own axis direction are provided with extension parts for inserting into the corresponding metal pipes, and the extension parts are in contact with the inner walls of the metal pipes.

[0006] In some embodiments of the present invention, an inner concave area is provided inside the docking ring.

[0007] In some embodiments of the present invention, the driving unit includes a first ring body, a plurality of support rollers circumferentially distributed around the first ring body and used for supporting the first ring body, a driving motor for providing power for the rotation of the first ring body, and a transmission wheel, and a clamping group for clamping the docking ring is arranged inside the first ring body.

[0008] In some embodiments of the present invention, the clamping group includes a second ring body disposed within a first ring body. A ring groove is formed on the inner circumferential wall of the second ring body, and threads are provided on the inner wall of the ring groove. An external thread ring connected to the threads is disposed within the ring groove. A plurality of inclined grooves are formed on the external thread ring, and guide posts are slidably disposed within the inclined grooves. A plurality of ejector posts are slidably disposed on the second ring body, and the ejector posts move along the radial direction of the second ring body. The guide posts are connected to the ejector posts. Among them, a plurality of setscrews for extruding and fixing the external thread ring are provided on the second ring body.

[0009] In some embodiments of the present invention, a plurality of pressing edges are provided at the end of the ejector post, and a plurality of pressing lines are provided on the outer circumferential wall of the docking ring.

[0010] In some embodiments of the present invention, the second ring body slides within the first ring body along the axial direction of the first ring body, and limiting edges for limiting the second ring body are provided at both ends of the first ring body.

[0011] In some embodiments of the present invention, the pushing unit includes a base, two side pulling bodies slidably disposed relative to the base, and a plurality of clamping groups located between the two side pulling bodies. The clamping groups are used for fixing a metal pipe. Each clamping group includes two soft belts facing each other. The soft belt is composed of a pressing area and a plurality of pressing belt areas located at each end of the pressing area. The plurality of pressing belt areas on the two soft belts cross each other, and the pressing belt areas are fixed to the side pulling bodies. Among them, a plurality of oil cylinders for providing power for its movement are provided on the base.

[0012] In some embodiments of the present invention, the sliding direction of the side pulling body on the base is inclined, and the sliding directions of the two side pulling bodies are opposite to each other. A support platform for lifting the bottom of each soft belt is further provided on the base.

[0013] Second aspect, a welding method for a thin-walled metal pipe, using the above-mentioned thin-walled metal pipe welding equipment, includes the following steps: Fix the docking ring on the driving unit. Fix the two metal pipes on the two pushing units respectively. Move the pushing unit so that the end of the metal pipe abuts against the end of the docking ring, and the end of the metal pipe contacts the conical surface on the docking ring. Use the driving unit to drive the rotation of the docking ring so that relative frictional movement is generated between the docking ring and the metal pipe, and both the conical surface and the end of the metal pipe are heated and softened. The driving unit provides a thrust force to the metal pipe, causing the softened part at the end of the metal pipe to undergo flaring deformation by using the conical surface, and increasing the contact area between the metal pipe and the docking ring; Continuously rotate the docking ring, causing the end of the metal pipe and the docking ring to undergo plastic flow under the action of extrusion force and be connected together, and the two metal pipes are welded and connected through the docking ring.

[0014] The beneficial effects of the present invention are as follows: By using the method of relative frictional movement of the docking ring with two metal pipes at the same time, the simultaneous welding connection work of the docking ring and the two metal pipes can be achieved, thereby realizing the connection of the two metal pipes. At the same time, by using the conical surfaces on both end faces of the docking ring to flare the end faces of the two metal pipes, the contact area between the metal pipe and the docking ring can be increased, thereby improving the welding strength; this welding method will not appear welding defects such as burn-through and breakage, and its welding firmness is effectively improved. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 is the structural schematic diagram of the present invention; Figure 2 is the schematic diagram of the docking state of the metal pipe and the docking ring in the embodiment of the present invention; Figure 3 is the cross-sectional structural schematic diagram of the docking ring in the embodiment of the present invention; Figure 4 is Figure 1 the explosion structural schematic diagram of; Figure 5 is the structural schematic diagram of the driving unit in the embodiment of the present invention; Figure 6 is the cross-sectional structural schematic diagram of the first ring body and the clamping group in the embodiment of the present invention; Figure 7 is the structural schematic diagram of the pushing unit in the embodiment of the present invention; Figure 8 is the structural schematic diagram of the clamping group in the embodiment of the present invention; Figure 9 is the explosion structural schematic diagram of the clamping group in the embodiment of the present invention.

[0017] Reference Signs: 100, metal pipe; 200. Docking ring; 201. Conical surface; 202. Extension part; 203. Concave area; 204. Embossed pattern 300. Driving unit; 301. First ring body; 302. Support roller; 303. Driving motor; 304. Transmission wheel; 305. Clamping group; 306. Second ring body; 307. Ring groove; 308. External thread ring; 309. Inclined groove; 310. Guide post; 311. Jacking post; 312. Set screw; 313. Pressing edge; 314. Flange 400. Pushing unit; 401. Base; 402. Side pulling body; 403. Soft belt; 404. Pressing area; 405. Pressing belt area; 406. Oil cylinder; 407. Moving seat; 408. Double-acting cylinder body; 409. Piston rod; 410. Support platform 500. Frame Detailed implementation mode

[0018] The following combines the drawings and embodiments to further describe in detail the specific implementation mode of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0019] As Figures 1 to 4 shown, a thin-walled metal pipe welding device of the present invention includes a docking ring 200 located between two metal pipes 100 and used for welding and connecting the two metal pipes 100, a driving unit 300 for providing rotational power for the docking ring 200, and two pushing units 400 for respectively providing pushing forces for the two metal pipes 100. The pushing force provided by the pushing unit 400 for the metal pipe 100 is along the axial direction of the metal pipe 100; Both end faces of the docking ring 200 along its own axis direction are set as conical surfaces 201, and the conical surfaces 201 are used to extrude the ends of the metal pipes 100 and make them flare and deform; In the present invention, the driving unit 300 and the two pushing units 400 can be installed on the frame 500 to facilitate providing a fixed position for the two metal pipes 100; the two metal pipes 100 are welded and connected through the docking ring 200, and the material used for the docking ring 200 is the same as that of the metal pipe 100; the setting direction of the shape of both end faces of the docking ring 200 as conical surfaces 201 can, when the pushing unit 400 pushes the metal pipe 100 to be in extrusion contact with the docking ring 200, the conical surfaces 201 can serve the purpose of flaring the ports of the metal pipes 100, so as to increase the contact area between the metal pipes 100 and the docking ring 200, thereby improving the welding strength. Of course, the deformation of the ports of the metal pipes 100 is carried out under the condition that they are heated and softened; the driving unit 300 can provide rotational power for the docking ring 200, so that the docking ring 200 and the metal pipe 100 can rotate relative to each other, and using the friction force between the docking ring 200 and the metal pipe 100, the softening welding work at the docking position of the metal pipe 100 and the docking ring 200 is realized; During use, the docking ring 200 is fixed on the driving unit 300. The two metal tubes 100 are respectively abutted against the two end faces of the docking ring 200, and the metal tubes 100 are fixed on the corresponding pushing units 400. The pushing units 400 can provide auxiliary thrust for the metal tubes 100 and the docking ring 200. When the driving unit 300 drives the docking ring 200 to rotate at a high speed, relative movement and frictional heat generation occur between the docking ring 200 and the ends of the metal tubes 100, softening the ends of the metal tubes 100. Due to the extrusion force between the metal tubes 100 and the conical surfaces 201, the conical surfaces 201 can flare the ends of the metal tubes 100, deforming the ends of the metal tubes 100 and increasing the contact area between the metal tubes 100 and the docking ring 200. Using the frictional high temperature between the metal tubes 100 and the docking ring 200, the welding connection between the metal tubes 100 and the docking ring 200 is realized; the docking ring 200 moves relative to the two metal tubes 100 by friction at the same time, so the two metal tubes 100 can be welded and connected by using the docking ring 200. It should be noted that since the conical surfaces 201 on the two end faces of the docking ring 200 are respectively abutted against the ends of the two metal tubes 100, the welding positions of the docking ring 200 and the metal tubes 100 are mainly concentrated on the conical surfaces 201, rather than the entire docking ring 200 needing to be heated and connected. By using the method that the docking ring 200 moves relative to the two metal tubes 100 by friction at the same time, the simultaneous welding connection between the docking ring 200 and the two metal tubes 100 can be realized, thereby realizing the connection of the two metal tubes 100. At the same time, by using the flaring treatment of the conical surfaces 201 on the two end faces of the docking ring 200 on the end faces of the two metal tubes 100, the contact area between the metal tubes 100 and the docking ring 200 can be increased, thereby improving the welding strength; this welding method will not have welding defects such as welding through and breakage, and its welding firmness is effectively improved.

[0020] In some embodiments of the present invention, as Figure 3 shown, extension parts 202 for inserting into the corresponding metal tubes 100 are provided on both end faces of the docking ring 200 along its own axis direction, and the extension parts 202 are attached to the inner walls of the metal tubes 100. When the metal tubes 100 are docked with the docking ring 200, the extension parts 202 on the docking ring 200 can be inserted into the metal tubes 100, thereby using the extension parts 202 to support the local metal tubes 100 in contact with the conical surfaces 201, increasing the contact area between the metal tubes 100 and the docking ring 200. When the ends of the metal tubes 100 are deformed by heat, the extension parts 202 can externally support the local area near the ends of the metal tubes 100, so that this position of the metal tubes 100 will not be deformed and flattened due to heat, improving the flatness of the welding positions of the metal tubes 100, and using the extension parts 202 can guide the metal tubes 100 moving towards the docking ring 200. It should be noted that relative frictional movement can also occur between the inner wall of the metal tube 100 and the extension portion 202, thereby increasing the frictional deformation area of the metal tube 100.

[0021] In some embodiments of the present invention, a concave area 203 is provided inside the docking ring 200; As Figure 3 shown, the setting of the concave area 203 can reduce the material used for the docking ring 200, make the overall weight of the docking ring 200 smaller, reduce costs, and can also reduce the heat storage amount and heat conduction amount inside the docking ring 200, reducing the temperature loss in the frictional area of the docking ring 200; It should be noted that the overall wall thickness of the docking ring 200 is consistent, and it is integrally processed by stamping or other methods during processing. This can simplify the processing method of the docking ring 200, and the shape of the docking ring 200 can be directly stamped out using a section of the specified pipeline; The stamping process can adopt methods such as mechanical stamping or hydraulic bulging.

[0022] In some embodiments of the present invention, as Figure 5 shown, the driving unit 300 includes a first ring body 301, a number of support rollers 302 circumferentially distributed around the first ring body 301 and used to support the first ring body 301, a driving motor 303 and a transmission wheel 304 used to provide power for the rotation of the first ring body 301. A clamping group 305 for clamping the docking ring 200 is provided inside the first ring body 301; Each support roller 302 can be installed on the frame 500. The setting of a number of support rollers 302 can provide support for the first ring body 301. And in order to limit the movement of the first ring body 301 along its own axis direction, baffles are provided at the ends of each support roller 302 to block the first ring body 301; The driving motor 303 is installed on the frame 500, the transmission wheel 304 is installed on the output end of the driving motor 303, and the transmission wheel 304 is in transmission connection with the first ring body 301. In this way, the driving motor 303 and the transmission wheel 304 can provide power for the rotational movement of the first ring body 301, and the first ring body 301 drives the docking ring 200 to rotate through the clamping group 305, thereby realizing the welding connection work between the docking ring 200 and the two metal tubes 100.

[0023] In some embodiments of the present invention, as Figure 6 shown, the clamping group 305 includes a second ring body 306 provided inside the first ring body 301. A ring groove 307 is opened on the circumferential inner wall of the second ring body 306. The inner wall of the ring groove 307 has threads. An external thread ring 308 connected to the threads is provided in the ring groove 307. A number of inclined grooves 309 are opened on the external thread ring 308, and guide posts 310 are slidably arranged in the inclined grooves 309; A number of ejector posts 311 are slidably arranged on the second ring body 306, and the ejector posts 311 move along the radial direction of the second ring body 306. The guide posts 310 are connected to the ejector posts 311. Among them, a number of setscrews 312 for extruding and fixing the external thread ring 308 are arranged on the second ring body 306. In the present invention, the first ring body 301 directly transmits the rotational power to the second ring body 306. The second ring body 306 can drive the docking ring 200 to rotate through its internal structure, thereby realizing power transmission. The annular groove 307 can provide an installation position for the external thread ring 308. And by using the thread connection method, when the external thread ring 308 moves in the annular groove 307, the external thread ring 308 can perform a rotational movement. A number of ejector posts 311 are circumferentially distributed around the axis of the second ring body 306, and the ejector posts 311 are slidably installed on the inner side wall of the annular groove 307. The sliding direction of the ejector posts 311 is along the radial direction of the second ring body 306. The setting of the inclined groove 309 can push the guide post 310 closer to or farther away from the axis of the second ring body 306 when the external thread ring 308 rotates, thereby providing power for the movement of the ejector posts 311. During use, the worker pushes the ejector posts 311 to a position farther away from the axis of the second ring body 306. At this time, the ejector posts 311 can use the inclined groove 309 and the guide posts 310 to rotate the external thread ring 308. When it is necessary to fix the docking ring 200, the setscrews 312 can be tightened so that the setscrews 312 reversely extrude the external thread ring 308. The external thread ring 308 uses the inclined groove 309 and the guide posts 310 thereon to push the ejector posts 311 to move towards the docking ring 200 direction. A number of ejector posts 311 move synchronously, thereby realizing the extrusion and fixing work of the docking ring 200. The function of the setscrews 312 is to extrude and lock the position of the external thread ring 308 to prevent it from moving randomly. The rotation of the setscrews 312 can be directly achieved by the worker twisting, or other methods such as a motor can also be used to achieve it.

[0024] In some embodiments of the present invention, such as Figure 3 and Figure 6 shown, a number of pressing edges 313 are arranged at the end of the ejector posts 311, and a number of press marks 204 are provided on the circumferential outer wall of the docking ring 200. The pressing edges 313 on the ejector posts 311 and the press marks 204 on the docking ring 200 are used in combination. When the pressing edges 313 are inserted into the corresponding press marks 204, the docking ring 200 is restricted in both its circumferential direction and axial direction, thereby preventing the docking ring 200 from sliding relative to the ejector posts 311 and ensuring that the docking ring 200 can rotate smoothly.

[0025] In some embodiments of the present invention, the second ring body 306 slides along the axis of the first ring body 301 within the first ring body 301. Stop edges 314 for limiting the second ring body 306 are arranged at both ends of the first ring body 301. Since the two driving units 400 provide opposite driving forces for the two metal tubes 100, the metal tubes 100 can be made to abut against the docking ring 200. In order to ensure the balance of the extrusion force between the docking ring 200 and the two metal tubes 100, the docking ring 200 can be in a freely movable state along its own axis. Thus, the extrusion and pushing of one driving unit 400 on the upper metal tube 100 is directly transmitted to the other metal tube 100 and the other driving unit 400 through the docking ring 200, so that the overlapping amount and welding area of the metal tubes 100 on the docking ring 200 are kept consistent; Since the first ring body 301 needs to drive the second ring body 306 to rotate, and the second ring body 306 can move within the first ring body 301, a number of transverse teeth can be provided on the inner wall of the first ring body 301 and the outer wall of the second ring body 306, such as Figure 6 shown, or a number of ridges can be provided on the inner wall of the first ring body 301, and a number of sliding grooves for cooperating with the ridges can be opened on the outer wall of the second ring body 306, thereby achieving the purpose of sliding and rotating of the second ring body 306 on the first ring body 301; the setting of the retaining edge 314 can prevent the second ring body 306 from sliding off the first ring body 301.

[0026] In some embodiments of the present invention, such as Figures 7 to 9 shown, the driving unit 400 includes a base 401, two side pull bodies 402 slidably arranged on the base 401, and a number of clamping groups located between the two side pull bodies 402, and the clamping groups are used for fixing the metal tube 100; The clamping group includes two soft belts 403 facing each other, and the soft belt 403 is composed of a pressing area 404 and a number of pressing belt areas 405 located at each end of the pressing area 404. A number of pressing belt areas 405 on the two soft belts 403 cross each other, and the pressing belt areas 405 are fixed on the side pull body 402; Among them, a number of oil cylinders 406 for providing power for its movement are arranged on the base 401; The base 401 can provide a support position for the two side pull bodies 402; since the driving unit 400 needs to provide a thrust for the metal tube 100, the base 401 can be slidably installed on the frame 500, and the oil cylinder 406 can provide power for the movement of the base 401, and the fixed end of the oil cylinder 406 can be installed on the frame 500; since the clamping group 305 can move horizontally within the first ring body 301, one base 401 can be fixedly connected to the frame 500, and the other base 401 can be slidably connected to the frame 500. In this way, by using the movable setting of one base 401, the extrusion work of the docking ring 200 and the two metal tubes 100 can be realized; The two side tension members 402 can provide support for a number of clamping groups therebetween, and the approaching or separating of the two side tension members 402 can drive the relative movement of the corresponding two flexible belts 403 within the clamping group; since the flexible belt 403 is composed of a pressing area 404 and a number of pressing belt areas 405, the flexible belt 403 can be wrapped around the outer wall of the metal tube 100. Of course, the wrapping method can be a way of helically winding multiple turns, or it can be as shown in Figure 8 shown, which only wraps a local area of the outer wall of the metal tube 100 in the circumferential direction, and the combined use of the two flexible belts 403 can achieve a full wrap of the circumference of the metal tube 100; as shown in Figure 8 shown, when the two ends of the flexible belt 403 approach each other, the wrapping areas of the two flexible belts 403 on the metal tube 100 overlap; The cross - setting of a number of pressing belt areas 405 on the two flexible belts 403 allows the two flexible belts 403 to move relatively. When the two side tension members 402 move away from each other, they can pull the two flexible belts 403 within the clamping group to move relatively, so that the two flexible belts 403 can achieve a full extrusion and fixation of the circumferential outer wall of the metal tube 100, thereby avoiding deformation of the metal tube 100 caused by stress concentration; the pressing area 404 on one flexible belt 403 is located inside the other flexible belt 403, and the pressing area 404 can be used to increase the contact area between the flexible belt 403 and the metal tube 100 as much as possible; The flexible belt 403 is at least one of structures such as a steel belt and a pulling belt.

[0027] In some embodiments of the present invention, as shown in Figure 7 shown, the sliding direction of the side tension member 402 on the base 401 is inclined, and the sliding directions of the two side tension members 402 are opposite; The base 401 also has a support platform 410 for lifting the bottom of each flexible belt 403; The inclined movement of the side tension member 402 can cause the side tension member 402 to have a movement tendency in both the horizontal and vertical directions. The movement of the two side tension members 402 in the horizontal direction can achieve the clamping or loosening of the metal tube 100 by the clamping group, and the movement of the two side tension members 402 in the vertical direction can pull the metal tube 100 downward and make the bottom of the flexible belt 403 contact the support platform 410, thereby achieving the extrusion and fixation of the metal tube 100 in the spatial direction, avoiding the shaking of the metal tube 100 due to the elasticity of the flexible belt 403 itself, and improving the fixing strength of the metal tube 100; To fix the position of the metal tube 100 in the horizontal direction, the two side tension members 402 need to be able to move synchronously. Specifically, as shown in Figure 7As shown, a moving seat 407 is vertically slidably arranged on the side wall of the base 401. A two-way cylinder body 408 is horizontally fixed on the moving seat 407. The piston rods 409 extend from both ends of the two-way cylinder body 408. The two piston rods 409 are respectively connected to the two side pulling bodies 402. In this way, the telescopic movement of the two piston rods 409 in the two-way cylinder body 408 can be realized by using the hydraulic method. And when one side pulling body 402 moves in the vertical direction, it will drive the moving seat 407 and the other side pulling body 402 to move synchronously.

[0028] A welding method for thin-walled metal pipes, using the above-mentioned welding equipment for thin-walled metal pipes, includes the following steps: Fix the docking ring 200 on the driving unit 300; Fix the two metal pipes 100 on the two pushing units 400 respectively; Move the pushing unit 400 to make the end of the metal pipe 100 abut against the end of the docking ring 200, and the end of the metal pipe 100 contacts the conical surface 201 on the docking ring 200; Use the driving unit 300 to drive the rotation of the docking ring 200 to generate relative frictional movement between the docking ring 200 and the metal pipe 100, and both the conical surface 201 and the end of the metal pipe 100 are heated and softened; The pushing unit 400 provides a thrust for the metal pipe 100, so that the softened part of the end of the metal pipe 100 undergoes flaring deformation by using the conical surface 201, and the contact area between the metal pipe 100 and the docking ring 200 increases; Continuously rotate the docking ring 200 to make the end of the metal pipe 100 and the docking ring 200 undergo plastic flow under the action of extrusion pressure and be connected together. The two metal pipes 100 are welded and connected through the docking ring 200.

[0029] Using the above method, the welding connection work of the two thin-walled metal pipes 100 can be realized, the contact area during welding is increased, and thus the welding strength is improved.

[0030] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A thin-walled metal pipe welding device, characterized in that, It includes a butt joint ring located between two metal pipes and used for welding and connecting the two metal pipes, a driving unit for providing rotational power to the butt joint ring, and two pushing units for respectively providing driving forces to the two metal pipes. The driving forces provided by the pushing units to the metal pipes are along the axial direction of the metal pipes. Both end faces of the butt joint ring along its own axial direction are set as conical surfaces, and the conical surfaces are used to extrude the ends of the metal pipes and make them flare and deform. The driving unit includes a first ring body, several support rollers circumferentially distributed around the first ring body and used for supporting the first ring body, a driving motor and a transmission wheel for providing power for the rotation of the first ring body. A clamping group for clamping the butt joint ring is arranged inside the first ring body.

2. A thin-walled metal pipe welding device according to claim 1, characterized in that, Both end faces of the butt joint ring along its own axial direction are provided with extension parts for inserting into the corresponding metal pipes, and the extension parts are in contact with the inner walls of the metal pipes.

3. The thin-walled metal pipe welding device according to claim 2, characterized in that, An inner concave area is arranged inside the butt joint ring.

4. A thin-walled metal pipe welding device according to claim 1, characterized in that, The clamping group includes a second ring body arranged inside the first ring body. A ring groove is formed on the circumferential inner wall of the second ring body. Threads are provided on the inner wall of the ring groove. An external thread ring connected to the threads is arranged in the ring groove. Several inclined grooves are formed on the external thread ring, and guide posts are slidably arranged in the inclined grooves. Several ejector posts are slidably arranged on the second ring body, and the ejector posts move along the radial direction of the second ring body. The guide posts are connected to the ejector posts. Among them, several set screws for extruding and fixing the external thread ring are arranged on the second ring body.

5. A thin-walled metal pipe welding device according to claim 4, characterized in that, Several pressing edges are arranged at the end of the ejector post, and several pressing lines are arranged on the circumferential outer wall of the butt joint ring.

6. The thin-walled metal pipe welding device according to claim 5, characterized in that, The second ring body slides inside the first ring body along the axial direction of the first ring body. Stop edges for limiting the second ring body are arranged at both ends of the first ring body.

7. A thin-walled metal pipe welding device according to claim 1, characterized in that, The pushing unit includes a base, two side pulling bodies slidably arranged relative to the base, and several clamping groups located between the two side pulling bodies. The clamping groups are used for fixing the metal pipes. The clamping group includes two soft belts with opposite directions. The soft belts are composed of a pressing area and several pressing belt areas located at each end of the pressing area. The several pressing belt areas on the two soft belts cross each other, and the pressing belt areas are fixed on the side pulling bodies. Among them, several oil cylinders for providing power for its movement are arranged on the base.

8. The thin-walled metal pipe welding device according to claim 7, wherein, The sliding directions of the side pulling bodies on the base are inclined, and the sliding directions of the two side pulling bodies are opposite. A supporting platform for lifting the bottom of each soft belt is further arranged on the base.

9. A welding method for thin-walled metal pipes, using a thin-walled metal pipe welding device as described in any one of claims 1-8, characterized in that, It includes the following steps: Fix the butt joint ring on the driving unit. Fix the two metal pipes on the two pushing units respectively. Move the pushing unit to make the end of the metal pipe abut against the end of the butt joint ring, and the end of the metal pipe contacts the conical surface on the butt joint ring. Use the driving unit to drive and rotate the butt joint ring to generate relative frictional movement between the butt joint ring and the metal pipe, and both the conical surface and the end of the metal pipe are heated and softened. The pushing unit provides a thrust to the metal pipe, so that the softened part of the end of the metal pipe undergoes flaring deformation by using the conical surface, and the contact area between the metal pipe and the butt joint ring increases. Continuously rotate the docking ring so that the end of the metal pipe and the docking ring undergo plastic flow under the action of extrusion pressure and are connected together, and the two metal pipes achieve the welding connection work through the docking ring.

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