Metal pipeline welding device

Abstract

The invention relates to the field of welding, in particular to a metal pipeline welding device which comprises a rotating table, a clamping assembly is arranged on the rotating table and used for clamping a flange welded to a pipeline, the pipeline is assembled on the flange, a welding assembly is arranged on one side of the rotating table and comprises a first air cylinder, and the output end of the first air cylinder is connected with a top plate. A gun body of electric arc welding equipment is arranged on the top plate, a base block is fixedly connected to the outer side wall of a gun barrel of the gun body, a rotating hole allowing the base block to deflect is formed in the end of the top plate, and the front end of the gun body extends to the connecting and welding position of a pipeline and a flange. According to the welding device, multi-layer welding is adopted, firstly, the sealing performance and the connecting strength between the flange and the pipeline can be effectively improved, the welding device can adapt to some severe environments and can resist media with higher flowing pressure, meanwhile, the welding device, the pipeline and the flange serve as moving parts and are matched with the rotating table, stable rotation can be achieved, and the gun body serves as a fixing part; and a moving part can be stably welded.

Description

Technical Field

[0001] This invention relates to the field of welding, specifically to a metal pipe welding apparatus. Background Technology

[0002] Welding metal pipes to flanges is a process that requires high precision, sealing, and strength. Considering the complex and diverse environments in which the finished product is used after welding, there are some special and harsh environments, such as some media with high impact, high media pressure, or harsh installation environments. The finished product itself may serve as a support for heavy objects such as equipment or instruments. In these cases, multiple welds are required between the pipe and the flange, that is, multiple layers of welding are required at the connection between the pipe and the flange.

[0003] For the aforementioned multi-pass welding process, the current operation method is to weld layer by layer. However, the upper layer welding needs to strictly follow the trajectory of the lower layer weld. At the same time, part of the upper layer welding needs to be fused to the lower layer weld, and another part needs to be fused to the pipe or flange. This has high welding requirements. Due to the current welding equipment and welding methods, it is difficult to achieve the expected results according to the above welding requirements.

[0004] Therefore, a metal pipe welding device is proposed to address the above problems. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: The metal pipe welding device of the present invention includes a rotating table, a clamping assembly is provided on the rotating table, the clamping assembly is used to clamp the flange to be welded to the pipe, the pipe is assembled on the flange, a welding assembly is provided on one side of the rotating table, the welding assembly includes a first cylinder, the output end of the first cylinder is connected to a top plate, the gun body of an arc welding device is provided on the top plate, a base block is fixed to the outer wall of the gun barrel of the gun body, a rotating hole is opened at the end of the top plate for the base block to deflect, and the front end of the gun body extends to the connection welding point between the pipe and the flange.

[0007] Preferably, a wedge-shaped block is provided on the lower rear surface of the gun body. The wedge-shaped block slides along the upper surface of the top plate. A second cylinder is fixed to the back of the wedge-shaped block. The second cylinder pushes the wedge-shaped block to squeeze the gun body, causing the gun body to deflect.

[0008] Preferably, the output end of the first cylinder is fixedly connected to a base plate, and a sliding groove for the top plate to slide is opened on the upper surface of the base plate. Sliding pins are fixedly connected to the two side walls of the top plate. The upper outer ring of the cylinder body of the first cylinder is symmetrically provided with guide rails, which extend upward at an incline, and the sliding pins are slidably connected in the guide rails.

[0009] Preferably, the rotary table includes a circular outer shell, a No. 1 plate is provided on the top of the outer shell, and a No. 2 plate is provided below the No. 1 plate. Multiple strip-shaped No. 1 sliding holes are arranged in a circumferential array on both the No. 1 and No. 2 plates. The multiple No. 1 sliding holes at the same height are arranged in a "+" shape. A clamping rod is provided in two No. 1 sliding holes that are opposite each other. A lead screw is threaded between two opposite clamping rods. The lead screw is located below the No. 1 plate, and the end of the lead screw extends to the outer edge of the No. 2 plate.

[0010] Preferably, two lead screws are arranged vertically between the two clamping rods, and the two lead screws between the same pair of clamping rods are arranged vertically on the upper and lower surfaces of the second plate.

[0011] Preferably, each of the clamping rods has an arc-shaped block at its upper end, and a wedge-shaped portion is provided on the inner edge of the upper surface of the arc-shaped block, which is used to press the flange downward.

[0012] Preferably, a third plate is provided below the second plate, a toothed ring is provided on the outer ring of the third plate, and multiple arc-shaped holes are arranged in a circular array on the third plate; Both the No. 2 plate and the No. 1 plate have multiple guide holes arranged in a circumferential array. The guide holes on the No. 2 plate correspond one-to-one with the guide holes on the No. 1 plate. The guide holes correspond one-to-one with the arc-shaped holes. Electric actuators are installed in the guide holes and arc-shaped holes that are opposite each other. The output end of the electric actuator extends upward to the upper surface of the No. 1 plate and rests on the lower end face of the pipe.

[0013] Preferably, a pressure stabilizing component is provided on the other side of the rotary table. The pressure stabilizing component is used to stabilize the pipeline on the flange. The pressure stabilizing component includes a third cylinder. A lifting plate is fixedly connected to the output end of the third cylinder. The end of the lifting plate extends upward toward the rotary table. A top block is connected to the end of the lifting plate. The top block is connected to the lifting plate through a driving component. The driving component can drive the top block to rotate synchronously with the pipeline.

[0014] Preferably, the top block is made of rubber and is in the shape of an inverted frustum.

[0015] Preferably, each of the sliding pins is rotatably connected to a sleeve.

[0016] The advantages of this invention are: 1. In this invention, multi-layer welding can effectively improve the sealing and connection strength between the flange and the pipe, adapt to some harsh environments, and resist media with greater flow pressure. At the same time, in this welding device, the pipe and flange are moving parts, which can rotate stably with the rotary table, and the welding gun body is a fixed part, which can stably weld the moving parts.

[0017] 2. In this invention, the arc-shaped block provided on the clamping rod is used to increase the effective contact area between the clamping rod and the flange, thereby improving the clamping effect of the clamping assembly on the flange. At the same time, the wedge-shaped part provided on the arc-shaped block has a downward squeezing force on the upper surface edge of the flange, which can squeeze the flange onto the rotating table, thereby improving the stability of the flange. During subsequent pipeline assembly, it can resist the horizontal squeezing of the pipeline on the flange and ensure the stability of the flange. Attached Figure Description

[0018] Figure 1 This is a first-view perspective perspective view of the welding device in this invention; Figure 2 This is a second-view perspective perspective view of the welding device in this invention; Figure 3 This is a front view of the welding apparatus in this invention; Figure 4 This is a top view of the welding apparatus in this invention; Figure 5 This is a schematic diagram of the internal structure of the rotary table in this invention; Figure 6 This is a perspective view of plate number one in this invention; Figure 7 This is a perspective view of plate number two in this invention; Figure 8 This is a perspective view of plate number three in this invention; Figure 9 This is a perspective view of the interaction between plate number three and the electric actuator in this invention; Figure 10 This is a perspective view of the welding assembly in this invention; Figure 11 This is a schematic diagram of the welding of the pipe and flange in this invention; Figure 12 This is a perspective view of the clamping rod in this invention; Figure 13 This is a schematic diagram showing the fit between the clamping rod and the flange in this invention.

[0019] In the diagram: 101, Flange; 102, Pipe; 1, Rotary table; 2, Cylinder No. 1; 3, Top plate; 4, Gun body; 5, Base block; 6, Rotary hole; 7, Wedge block; 8, Cylinder No. 2; 9, Base plate; 10, Sliding pin; 11, Guide rail; 12, Outer shell; 13, Plate No. 1; 14, Plate No. 2; 15, Sliding hole No. 1; 16, Clamping rod; 17, Lead screw; 18, Arc block; 19, Wedge part; 20, Gear ring; 21, Plate No. 3; 22, Arc hole; 23, Guide hole; 24, Electric actuator; 25, Cylinder No. 3; 26, Lifting plate; 27, Top block; 28, Sleeve. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0021] Reference Figure 1 - Figure 5 ,as well as Figure 10 - Figure 11 A metal pipe welding device includes a rotary table 1, a clamping assembly on the rotary table 1 for clamping a flange 101 to be welded to a pipe 102, the flange 101 being fitted with the pipe 102, a welding assembly on one side of the rotary table 1, the welding assembly including a first cylinder 2, the output end of the first cylinder 2 being connected to a top plate 3, an arc welding gun body 4 on the top plate 3, a base block 5 fixed to the outer wall of the gun barrel of the gun body 4, a rotating hole 6 for the base block 5 to deflect at the end of the top plate 3, and the front end of the gun body 4 extending to the connection and welding point between the pipe 102 and the flange 101. In this embodiment of the invention, the rotary table 1 is further provided with an execution component that drives its rotation. Specifically, the execution component includes a servo motor, the output end of which is fixedly connected to a drive tooth, the drive tooth meshing with a driven tooth, and the driven tooth being fixedly connected to the rotary table 1 along the same axis. The specific operation of this welding device is as follows: First, the flange 101 is placed horizontally on the rotary table 1 with its welding position facing upwards. Then, the clamping assembly is driven to clamp and fix the flange 101 on the rotary table 1. Next, the pipe 102 matching the flange 101 is assembled, with the lower end of the pipe 102 inserted into the inner ring of the flange 101. Then, the welding operation is performed. In the initial state of the welding assembly, the first cylinder 2 raises the torch body 4 to make room for the flange 101 and the pipe 102. When the welding operation is performed, the first cylinder 2 moves the torch body 4 downwards, with the tip of the torch pointing towards the welding position of the pipe 102 and the flange 101, and drives the arc welding equipment. At the same time, the execution assembly is also driven, causing the flange 101 and the pipe 102 to rotate synchronously. At this time, the torch body 4 performs welding while the flange 101 and the pipe 102 rotate. After the flange 101 and the pipe 102 have rotated one revolution, the first weld is completed. Figure 11 Weld pass A in the middle; After weld A is completed, pause the execution and welding components, and adjust the angle of the torch 4 so that its tip points to the junction of the lower edge of weld A and flange 101. Drive the arc welding equipment, simultaneously driving the execution component. The execution component causes flange 101 and pipe 102 to rotate synchronously. At this time, the torch 4 welds while flange 101 and pipe 102 rotate. After flange 101 and pipe 102 have rotated one revolution, the second weld is completed. Figure 11 Weld B in the middle, weld B covers weld A and flange 101; After weld B is completed, pause the execution and welding components, and adjust the angle of the torch 4 so that its tip points to the upper edge of weld A. Drive the arc welding equipment, simultaneously driving the execution component. The execution component causes flange 101 and pipe 102 to rotate synchronously. At this time, the torch 4 welds while flange 101 and pipe 102 rotate. After flange 101 and pipe 102 have rotated one revolution, the third weld is completed. Figure 11 The C weld bead covers pipe 102, the A weld bead, and the B weld bead. Multi-layer welding of weld beads A, B, and C can effectively improve the sealing and connection strength between flange 101 and pipe 102, adapt to some harsh environments, and resist media with higher flow pressure. At the same time, the pipe 102 and flange 101 are moving parts, which can rotate stably with the rotary table 1, and the gun body 4 is a fixed part, which can stably weld the moving parts.

[0022] Reference Figure 3 , Figure 5 , Figure 10 and Figure 11 The lower rear surface of the gun body 4 is provided with a wedge block 7. The wedge block 7 slides along the upper surface of the top plate 3. A second cylinder 8 is fixed to the back of the wedge block 7. The second cylinder 8 pushes the wedge block 7 to squeeze the gun body 4, causing the gun body 4 to deflect. The wedge block 7 has torsion springs on both sides of the rotating shaft. The torsion of the torsion springs allows the rear end of the gun body 4 to be attached to the top plate 3. The wedge block 7 is located below the rear end of the gun body 4. The wedge block 7 is driven by the second cylinder 8 and can move along the upper surface of the top plate 3. When the wedge block 7 moves forward, it pushes the gun body 4 upward. The gun body 4 deflects counterclockwise around the rotating shafts on both sides of the wedge block 7. When the wedge block 7 moves backward, the gun body 4 deflects clockwise around the rotating shafts on both sides of the wedge block 7. This allows for the adjustment of the front end angle of the gun body 4, thereby enabling the welding of different weld beads. After adjustment, the angle of the gun body 4 can remain stable, maintaining the formation of weld beads at different angles.

[0023] Reference Figure 3 and Figure 10 The output end of the first cylinder 2 is fixedly connected to a base plate 9. A sliding groove for the top plate 3 to slide is opened on the upper surface of the base plate 9. Sliding pins 10 are fixedly connected to the two side walls of the top plate 3. A guide rail 11 is symmetrically provided on the outer ring of the upper end of the cylinder body of the first cylinder 2. The guide rail 11 extends upward at an incline, and the sliding pin 10 is slidably connected in the guide rail 11. When cylinder 2 pushes the gun body 4, the top plate 3 moves along the guide rail 11. At the same time, the inclined part of the guide rail 11 can guide the top plate 3 to move towards the pipe 102, and the top plate 3 can move horizontally along the bottom plate 9. At this time, the top plate 3 not only moves vertically, but also moves horizontally and away from the pipe 102. More operating space is freed up on the rotary table 1, which helps to load the flange 101 and unload the welded product of the flange 101 and the pipe 102.

[0024] Reference Figure 1 - Figure 9 The rotating table 1 includes a circular outer shell 12. A first plate 13 is provided on the top of the outer shell 12, and a second plate 14 is provided below the first plate 13. Multiple strip-shaped first sliding holes 15 are arranged in a circular array on both the first plate 13 and the second plate 14. The multiple first sliding holes 15 at the same height are arranged in a "+" shape. A clamping rod 16 is provided in two first sliding holes 15 that are opposite each other. A lead screw 17 is threaded between the two opposite clamping rods 16. The lead screw 17 is located below the first plate 13, and the end of the lead screw 17 extends to the outer edge of the second plate 14. Each lead screw 17 is connected to a motor that drives its rotation. The motor is controlled by a PLC and can realize the forward or reverse rotation of the lead screw 17. When placing the flange 101, the lead screw 17 drives the clamping rod 16 to move away from the center of the rotary table 1 in a synchronous manner. Then the flange 101 is placed. At this time, there is no need to adjust the position of the flange 101. Just place the flange 101 between the multiple clamping rods 16. Then drive the lead screw 17 to reverse, and the multiple clamping rods 16 move towards the flange 101 in a synchronous manner and clamp the flange 101 at the center position of the rotary table 1. That is, the axis of the flange 101 and the rotation axis of the rotary table 1 are on the same line. Then the pipe 102 is placed and inserted into the flange 101. Then the welding operation is performed.

[0025] Reference Figure 1 - Figure 9 ,as well as Figure 12 and Figure 13 Two lead screws 17 are arranged vertically between the two clamping rods 16, and the two lead screws 17 between the same pair of clamping rods 16 are arranged vertically on the upper surface and the lower surface of the second plate 14. Two lead screws 17 are arranged vertically between the two opposing clamping rods 16. This increases the pushing force of the lead screws 17 on the clamping rods 16, allowing the clamping rods 16 to smoothly move the flange 101 to the center position of the rotary table 1. It also increases the clamping force of the clamping rods 16 on the flange 101. After the flange 101 is centered on the rotary table 1, the pipe 102 is assembled. During the assembly of the pipe 102, a compressive force is generated on the flange 101 to prevent the flange 101 from shifting. This ensures that the axes of the flange 101, the pipe 102, and the rotary table 1 are aligned, providing a guarantee for subsequent welding.

[0026] Reference Figure 12 and Figure 13 Each of the clamping rods 16 has an arc-shaped block 18 at its upper end, and a wedge-shaped part 19 is provided on the inner edge of the upper end surface of the arc-shaped block 18. The wedge-shaped part 19 is used to press the flange 101 downward. The arc-shaped block 18 provided on the clamping rod 16 is used to increase the effective contact area between the clamping rod 16 and the flange 101, and improve the clamping effect of the clamping assembly on the flange 101. At the same time, the wedge-shaped part 19 provided on the arc-shaped block 18 has a downward extrusion force on the upper surface edge of the flange 101, which can press the flange 101 onto the rotary table 1, thereby improving the stability of the flange 101. When the pipe 102 is assembled laterally, it can resist the horizontal extrusion of the pipe 102 on the flange 101, ensuring the stability of the flange 101.

[0027] Reference Figure 5 and Figure 9 Below the second plate 14, a third plate 21 is provided. A toothed ring 20 is provided on the outer ring of the third plate 21, and multiple arc-shaped holes 22 are arranged in a circular array on the third plate 21. Multiple guide holes 23 are arranged in a circular array on both the second plate 14 and the first plate 13. The guide holes 23 on the second plate 14 correspond one-to-one with the guide holes 23 on the first plate 13. The guide holes 23 correspond one-to-one with the arc-shaped holes 22. Electric actuators 24 are provided in the guide holes 23 and arc-shaped holes 22 that are opposite each other. The output end of the electric actuators 24 extends upward to the upper surface of the first plate 13 and rests on the lower end surface of the pipe 102. The geared ring 20 is connected to a geared motor, which is controlled by a PLC. The geared motor can rotate the geared ring 20 forward or backward, thereby enabling the third plate 21 to rotate forward or backward. Specifically, when the third plate 21 rotates, the arc-shaped hole 22 on it will squeeze the electric push rod 24, which will then move along the guide hole 23 and move synchronously with the multiple electric push rods 24. In this embodiment, the electric push rod 24 is used to hold the pipe 102 in place. When welding the pipe 102 and the flange 101, a certain distance must be maintained between the lower end face of the pipe 102 and the lower surface of the flange 101 to meet the welding requirements. Therefore, the electric push rod 24 is provided to drive the output end of the electric push rod 24 to move up or down, controlling the distance between the lower end of the pipe 102 and the lower surface of the flange 101. The electric push rod 24 can move along the guide hole 23 to adjust the diameter of the circle formed by the multiple electric push rods 24, thereby adapting to the welding of pipes 102 and flanges 101 with different diameters and having high flexibility.

[0028] Reference Figure 5 The other side of the rotary table 1 is provided with a pressure stabilizing component. The pressure stabilizing component is used to stabilize the pipe 102 on the flange 101. The pressure stabilizing component includes a third cylinder 25. The output end of the third cylinder 25 is fixedly connected to a lifting plate 26. The end of the lifting plate 26 extends upward toward the rotary table 1. The end of the lifting plate 26 is connected to a top block 27. The top block 27 is connected to the lifting plate 26 through a driving component. The driving component can drive the top block 27 to rotate synchronously with the pipe 102. The pressure stabilizing component is used to press down the pipe 102, providing stable support for the rotation of the flange 101 and the pipe 102. Specifically, after the pipe 102 is assembled onto the flange 101, the third cylinder 25 drives the lifting plate 26 to move down, and the lifting plate 26 drives the top block 27 to press down on the pipe 102. The top block 27 is connected to the drive component on the lifting plate 26. The drive component is a synchronous motor. The rotation direction and speed of the synchronous motor are the same as the rotation direction and speed of the rotary table 1, and the rotation axis of the top block 27 is colinear with the axis of the rotary table 1. After the top block 27 is pressed down on the pipe 102, the top block 27 rotates synchronously with the rotation, and then welding is performed.

[0029] Reference Figure 5 The top block 27 is made of rubber and is an inverted frustum. The shape of the top block 27 allows the lower end of the top block 27 to be inserted into the upper port of the pipe 102, further improving the stability between the top block 27 and the pipe 102. Furthermore, the top block 27 can be adapted to pressing pipes 102 of different diameters.

[0030] Reference Figure 10Each of the sliding pins 10 is rotatably connected to a sleeve 28; the sleeve 28 is used to convert the sliding friction between the sliding pin 10 and the guide rail 11 into rolling friction between the sleeve 28 and the guide rail 11, thereby reducing resistance and improving the smoothness of the horizontal movement of the top plate 3.

[0031] Working Principle: The welding device operates as follows: First, the flange 101 is placed horizontally on the rotating table 1 with its welding position facing upwards. Then, the clamping assembly is driven to clamp and fix the flange 101 on the rotating table. Next, the pipe 102, which matches the flange 101, is installed, with the lower end of the pipe 102 inserted into the inner ring of the flange 101. Then, the welding operation is performed. In the initial state of the welding assembly, the first cylinder 2 raises the torch body 4 to make room for the flange 101 and the pipe 102. When the welding operation is performed, the first cylinder 2 moves the torch body 4 downwards, with the tip of the torch pointing towards the welding position of the pipe 102 and the flange 101, and drives the arc welding equipment. At the same time, the execution assembly is also driven, causing the flange 101 and the pipe 102 to rotate synchronously. At this time, the torch body 4 performs welding while the flange 101 and the pipe 102 rotate simultaneously. After the flange 101 and the pipe 102 have rotated one revolution, the first weld is completed. Figure 11 Weld pass A in the middle; After weld A is completed, pause the execution and welding components, and adjust the angle of the torch 4 so that its tip points to the junction of the lower edge of weld A and flange 101. Drive the arc welding equipment, simultaneously driving the execution component. The execution component causes flange 101 and pipe 102 to rotate synchronously. At this time, the torch 4 welds while flange 101 and pipe 102 rotate. After flange 101 and pipe 102 have rotated one revolution, the second weld is completed. Figure 11 Weld B in the middle, weld B covers weld A and flange 101; After weld B is completed, pause the execution and welding components, and adjust the angle of the torch 4 so that its tip points to the upper edge of weld A. Drive the arc welding equipment, simultaneously driving the execution component. The execution component causes flange 101 and pipe 102 to rotate synchronously. At this time, the torch 4 welds while flange 101 and pipe 102 rotate. After flange 101 and pipe 102 have rotated one revolution, the third weld is completed. Figure 11 The C weld bead covers pipe 102, the A weld bead, and the B weld bead.

[0032] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal pipe welding device, characterized in that: It includes a rotary table, on which a clamping assembly is installed. The clamping assembly is used to clamp a flange to be welded to a pipe. The flange is fitted with a pipe. A welding assembly is installed on one side of the rotary table. The welding assembly includes a first cylinder. The output end of the first cylinder is connected to a top plate. The top plate is equipped with the gun body of an arc welding device. A base block is fixed to the outer wall of the gun barrel of the gun body. A rotating hole is opened at the end of the top plate for the base block to deflect. The front end of the gun body extends to the connection and welding point between the pipe and the flange.

2. The metal pipe welding device according to claim 1, characterized in that: The lower rear surface of the gun body is provided with a wedge-shaped block. The wedge-shaped block slides along the upper surface of the top plate. A second cylinder is fixed to the back of the wedge-shaped block. The second cylinder pushes the wedge-shaped block to squeeze the gun body, causing the gun body to deflect.

3. The metal pipe welding device according to claim 2, characterized in that: The output end of the No. 1 cylinder is fixedly connected to a base plate. A sliding groove for the top plate to slide is opened on the upper surface of the base plate. Sliding pins are fixedly connected to the two side walls of the top plate. Guide rails are symmetrically provided on the outer ring of the upper end of the cylinder body of the No. 1 cylinder. The guide rails extend upward at an angle, and the sliding pins are slidably connected in the guide rails.

4. The metal pipe welding device according to claim 1, characterized in that: The rotary table includes a circular outer shell, with a No. 1 plate on the top of the shell and a No. 2 plate below the No. 1 plate. Multiple strip-shaped No. 1 sliding holes are arranged in a circumferential array on both the No. 1 and No. 2 plates. The multiple No. 1 sliding holes at the same height are arranged in a "+" shape. A clamping rod is provided in two No. 1 sliding holes that are opposite each other. A lead screw is threaded between two opposite clamping rods. The lead screw is located below the No. 1 plate, and the end of the lead screw extends to the outer edge of the No. 2 plate.

5. A metal pipe welding apparatus according to claim 4, characterized in that: Two lead screws are arranged vertically between the two clamping rods, and the two lead screws between the same pair of clamping rods are arranged vertically on the upper and lower surfaces of the second plate.

6. A metal pipe welding apparatus according to claim 5, characterized in that: Each clamping rod has an arc-shaped block at its upper end, and a wedge-shaped part is provided on the inner edge of the upper end face of the arc-shaped block. The wedge-shaped part is used to press the flange downward.

7. A metal pipe welding apparatus according to claim 5, characterized in that: A third plate is set below the second plate, and a toothed ring is set on the outer ring of the third plate. Multiple arc-shaped holes are arranged in a circular array on the third plate. Both the No. 2 plate and the No. 1 plate have multiple guide holes arranged in a circumferential array. The guide holes on the No. 2 plate correspond one-to-one with the guide holes on the No. 1 plate. The guide holes correspond one-to-one with the arc-shaped holes. Electric actuators are installed in the guide holes and arc-shaped holes that are opposite each other. The output end of the electric actuator extends upward to the upper surface of the No. 1 plate and rests on the lower end face of the pipe.

8. A metal pipe welding apparatus according to claim 4, characterized in that: On the other side of the rotary table is a pressure stabilizing component, which is used to stabilize the pipeline on the flange. The pressure stabilizing component includes a No. 3 cylinder, and a lifting plate is fixed to the output end of the No. 3 cylinder. The end of the lifting plate extends upward toward the rotary table, and a top block is connected to the end of the lifting plate. The top block is connected to the lifting plate through a drive component, and the drive component can drive the top block to rotate synchronously with the pipeline.

9. A metal pipe welding apparatus according to claim 8, characterized in that: The top block is made of rubber and is in the shape of an inverted frustum.

10. A metal pipe welding apparatus according to claim 3, characterized in that: Each of the aforementioned sliding pins is rotatably connected to a sleeve.

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