Auxiliary welding device for steel pipes used in construction

Abstract

This invention provides an auxiliary welding device for steel pipes used in construction, relating to the field of building construction technology. It includes: a welding base; clamping seats are provided at both ends of the welding base, one clamping seat is fixedly connected to the welding base, and the lower end of the other clamping seat is slidably tangent to the top of the welding base. Two directional guide rods are vertically arranged on the sliding clamping seat facing the fixed clamping seat, with the ends of the guide rods passing through the fixed clamping seat. In this invention, the fixed clamping seats and sliding clamping seats at both ends of the welding base are combined with an elastic reset mechanism (directional guide rods, alignment springs, and plugs), achieving flexible compensation and pressure equalization for steel pipe joining.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to an auxiliary welding device for steel pipes used in construction. Background Technology

[0002] In the construction of steel structures, circumferential welding of steel pipes is a critical process for pipe connections. Traditional welding operations typically involve manually holding clamps to secure the steel pipes and visually adjusting the butt joint position before welding. This method suffers from problems such as large deviations in the coaxiality of the steel pipes and uneven end-face contact, easily leading to defects such as weld porosity and incomplete fusion. Especially in long-distance pipeline construction, the cumulative error of multiple pipe sections can cause overall axial misalignment, severely impacting structural safety. While existing mechanical welding devices can clamp the steel pipes, they mostly use rigid clamping mechanisms, lacking buffering compensation during pipe butt joints. Hard impacts to the end faces can easily cause deformation of the pipe ends. Furthermore, the clamping structure is separate from the rotation drive system, requiring manual intervention to adjust the welding angle, making it difficult to ensure the continuity of the circumferential weld. In addition, conventional positioning devices and welding actuators lack timing coordination; after the positioning components are removed, slight displacement of the steel pipe often occurs, causing a shift in the welding starting point, requiring repeated calibration. Summary of the Invention

[0003] This invention relates to an auxiliary welding device for steel pipes used in construction, in order to solve the technical bottlenecks of low positioning accuracy, unstable welding quality and high dependence on manual labor in traditional processes.

[0004] This invention provides an auxiliary welding device for steel pipes used in construction, specifically comprising: a welding base; clamping seats at both ends of the welding base, one clamping seat being fixedly connected to the welding base, and the lower end of the other clamping seat being slidably tangent to the top of the welding base; two directional guide rods perpendicularly arranged on the sliding clamping seat toward the fixed clamping seat, the ends of the directional guide rods passing through the fixed clamping seat, and end caps provided at the ends of the directional guide rods; a positioning spring fitted on the directional guide rod between the end caps and the fixed clamping seat; clamping blocks symmetrically slidably arranged on the clamping seats, the two clamping blocks moving in opposite directions to clamp steel pipes, the clamping blocks on the two clamping seats clamping two oppositely connected steel pipes respectively; a welding frame is longitudinally fixedly installed on the welding base between the two clamping seats, a controller is fixedly installed at the front end of the welding frame, a welding cylinder is fixedly installed at one end of the top of the welding frame, a connecting block is fixedly connected to the piston rod end of the welding cylinder, the connecting block being always slidably tangent to the upper end of the welding frame; a welding frame is fixedly installed at one end of the connecting block, and a positioning frame is fixedly installed at the other end.

[0005] Optionally, a double-ended lead screw is rotatably installed between the two ends of the top of the clamping seat. Two clamping blocks are respectively vertically screwed onto the opposite thread of the double-ended lead screw. The lower end of the clamping block is slidably engaged with a T-rail fixedly provided at the upper end of the clamping seat. A synchronous motor is fixedly provided at one end of the clamping seat. The synchronous motor is used to drive the double-ended lead screw to rotate. The rotation of the double-ended lead screw drives the two clamping blocks to move synchronously in opposite directions to clamp the steel pipe, and to move synchronously in opposite directions to release the steel pipe.

[0006] Optionally, an arc-shaped support plate is fixedly provided at the middle of the opposite end of each of the two clamping seats, and the lower end of the steel pipe to be welded is supported on the support plate.

[0007] Optionally, clamping rollers are rotatably installed at the upper and lower ends of the two opposing clamping blocks, and the clamped steel pipe is positioned between the four clamping rollers. A rotary motor is fixedly installed on the clamping block at one of the clamping rollers. The rotating shaft of the rotary motor is connected to the end rotating shaft of the adjacent clamping roller via a belt. When the rotary motor operates, it drives the clamping roller, which in turn drives the steel pipe in the clamped state to rotate to facilitate circumferential welding.

[0008] Optionally, a positioning blind plate is fixedly provided at the upper end of the positioning frame facing the joint of the two steel pipes, and a fan-shaped patch is provided at the circumferential edge of the positioning blind plate to be attached to the outer wall of the two steel pipes.

[0009] Optionally, a welding cantilever is fixedly provided horizontally at the upper end of the welding frame toward the welding point, and a welding head is fixedly provided at one end of the welding cantilever toward the welding point. A contact seat is fixedly provided on the welding cantilever, and two symmetrical buffer rods are vertically slidably provided at the upper and lower ends of the contact seat. A contact wheel is rotatably connected between the ends of each set of buffer rods. The contact wheel is close to the steel pipe, and a buffer spring is fitted on the buffer rod. When the welding frame moves with the connecting block toward the side where the steel pipe is located, the contact wheel first contacts the steel pipe, and then the welding head approaches the circumferential seam.

[0010] Optionally, when the two steel pipes are respectively fixed on the two clamping seats, the positioning blind plate of the positioning frame is at the joint of the two steel pipes. The piston rod of the welding cylinder is pushed out, the connecting block moves, and the positioning frame and welding frame move synchronously. The positioning blind plate is removed from between the two steel pipes. At the same time, under the action of the alignment spring, the sliding clamping seat moves, and the steel pipe on it moves closer to the other fixed steel pipe and joins it. The circumferential seam of the joint is directly opposite the welding head, the contact wheel abuts against the wall of the steel pipe, and the welding head welds the circumferential seam.

[0011] This invention provides an auxiliary welding device for steel pipes used in construction, which has the following advantages:

[0012] In this invention, the fixed clamping seats and sliding clamping seats at both ends of the welding base are combined with an elastic reset mechanism (guide rod, alignment spring, and plug) to achieve flexible compensation and pressure equalization for steel pipe butt welding. Guided by the elastic reset mechanism, the sliding clamping seat slides precisely along the guide rod, eliminating manual adjustment errors and avoiding deformation or displacement caused by hard impacts to the steel pipe end face, ensuring the coaxiality and uniformity of the circumferential seam butt welding. The clamping block, driven by a double-ended lead screw and a synchronous motor, forms a four-point clamping structure guided by a T-rail. Combined with the rotational drive function of the clamping rollers, this achieves stable fixing of the steel pipe and allows the steel pipe to rotate at a uniform speed via a rotary motor, enabling continuous welding along the circumferential seam trajectory. The weld uniformity is significantly better than traditional manual welding.

[0013] In this invention, the linkage design of the positioning frame and welding frame achieves seamless connection between positioning and welding actions through the timing control of the welding cylinder. The fan-shaped abutment of the positioning blind plate is initially embedded in the gap between the steel pipes, and radial pre-positioning is achieved through the contact of the circumferential edge with the outer wall of the steel pipe, ensuring that the axes of the two steel pipes coincide. When the welding cylinder pushes the connecting block, the retraction of the positioning blind plate and the elastic advancement of the sliding clamp seat are synchronized, avoiding interference of the positioning components with the welding path and achieving impact-free butt welding of the steel pipe ends using an elastic reset mechanism. The contact wheel of the welding frame forms an adaptive clamping mechanism through a buffer spring and a buffer rod, pre-applying to the surface of the steel pipe before the welding head contacts the circumferential seam, effectively absorbing mechanical vibration and axial deviation, ensuring a constant distance between the welding head and the circumferential seam, and improving welding stability and penetration consistency.

[0014] Furthermore, the arc-shaped support plate design simplifies the initial positioning process of the steel pipe. Operators only need to place the steel pipe on the support plate, and the clamping blocks will automatically complete the centering and clamping, significantly reducing labor intensity. The entire device coordinates the linkage of the synchronous motor, rotary motor, and welding cylinder through the controller, realizing fully automated operation from steel pipe clamping and positioning to circumferential welding. This not only greatly shortens the welding cycle but also reduces reliance on skilled operators, making it particularly suitable for the standardized welding needs of large quantities of steel pipes in the construction industry. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0016] The accompanying drawings described below are only related to some embodiments of the invention and are not intended to limit the invention.

[0017] In the attached diagram:

[0018] Figure 1 A schematic diagram of the first axial view structure of the present invention is shown;

[0019] Figure 2A schematic diagram of the second axial view structure of the present invention is shown;

[0020] Figure 3 A schematic diagram of the steel pipe removal state of the present invention is shown;

[0021] Figure 4 A schematic axial view of the welding frame portion of the present invention is shown;

[0022] Figure 5 The present invention is shown Figure 4 Schematic diagram of the A-section structure;

[0023] Figure 6 This diagram shows an axial view of the two clamping seats of the present invention in a separated state.

[0024] Figure 7 A schematic axial view of the clamping seat and clamping block of the present invention is shown.

[0025] Attached Figure

[0026] 1. Welding base;

[0027] 2. Clamping seat; 201. Double-ended lead screw; 202. Synchronous motor; 203. Guide rod; 2031. Plug; 2032. Alignment spring; 204. Support plate;

[0028] 3. Clamping block; 301. Clamping roller; 302. Rotary motor;

[0029] 4. Welding frame; 401. Welding cylinder; 402. Connecting block;

[0030] 5. Controller;

[0031] 6. Positioning frame; 601. Positioning blind plate;

[0032] 7. Welding frame; 701. Welding cantilever; 702. Welding head; 703. Contact seat; 704. Buffer rod; 705. Contact wheel; 706. Buffer spring;

[0033] 8. Steel pipes. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: Please refer to Figures 1 to 7 :

[0036] This invention proposes an auxiliary welding device for steel pipes used in construction, comprising: a welding base 1; clamping seats 2 are respectively provided at both ends of the welding base 1, one clamping seat 2 is fixedly connected to the welding base 1, and the lower end of the other clamping seat 2 is slidably tangent to the top of the welding base 1, and two directional guide rods 203 are vertically provided on the sliding clamping seat 2 facing the fixed clamping seat 2, the end of the directional guide rod 203 passes through the fixed clamping seat 2, and the end of the directional guide rod 203 is provided with a plug 2031, and a positioning spring 2032 is fitted on the directional guide rod 203 between the plug 2031 and the fixed clamping seat 2; Clamping blocks 3 are symmetrically slidably provided on clamping base 2. The two clamping blocks 3 move in opposite directions to clamp the steel pipes 8. The clamping blocks 3 on the two clamping bases 2 respectively clamp two steel pipes 8 that are connected to each other. Welding machine frame 4 is longitudinally fixedly installed on welding base 1 between the two clamping bases 2. Controller 5 is fixedly installed at the front end of welding machine frame 4. Welding cylinder 401 is fixedly installed at one end of the top of welding machine frame 4. Connecting block 402 is fixedly connected to the piston rod end of welding cylinder 401. Connecting block 402 is always slidably tangential to the upper end of welding machine frame 4. Welding frame 7 is fixedly installed at one end of connecting block 402, and positioning frame 6 is fixedly installed at the other end.

[0037] The clamping seat 2 has a double-ended lead screw 201 rotatably mounted between its two ends. Two clamping blocks 3 are vertically screwed onto the opposite threads of the double-ended lead screw 201. The lower end of the clamping block 3 is slidably engaged with the T-rail fixed at the upper end of the clamping seat 2. A synchronous motor 202 is fixed at one end of the clamping seat 2. The synchronous motor 202 is used to drive the double-ended lead screw 201 to rotate. The rotation of the double-ended lead screw 201 drives the two clamping blocks 3 to move synchronously in opposite directions to clamp the steel pipe 8, and to move synchronously in opposite directions to release the steel pipe 8.

[0038] Among them, an arc-shaped support plate 204 is fixedly provided at the middle of the opposite end of each of the two clamping seats 2, and the lower end of the steel pipe 8 to be welded is supported on the support plate 204.

[0039] In this arrangement, clamping rollers 301 are rotatably mounted on the upper and lower ends of two opposing clamping blocks 3, and the clamped steel pipe 8 is positioned between four clamping rollers 301. A rotary motor 302 is fixedly mounted on the clamping block 3 at one of the clamping rollers 301. The rotating shaft of the rotary motor 302 is connected to the end rotating shaft of the adjacent clamping roller 301 via a belt. When the rotary motor 302 operates, it drives the clamping roller 301, which in turn drives the steel pipe 8 in the clamped state to rotate to facilitate circumferential welding.

[0040] The upper end of the positioning frame 6 is fixedly provided with a positioning blind plate 601 facing the joint of the two steel pipes 8. The circumferential edge of the positioning blind plate 601 is provided with a fan-shaped patch that is attached to the outer wall of the two steel pipes 8.

[0041] The upper end of the welding frame 7 is horizontally fixed to the welding point with a welding cantilever 701. The end of the welding cantilever 701 facing the welding point is fixed with a welding head 702. A contact seat 703 is fixed on the welding cantilever 701. Two symmetrical buffer rods 704 are vertically slidably mounted on the upper and lower ends of the contact seat 703. A contact wheel 705 is rotatably connected between the ends of each set of buffer rods 704. The contact wheel 705 is close to the steel pipe 8. A buffer spring 706 is mounted on the buffer rod 704. When the welding frame 7 moves with the connecting block 402 to the side where the steel pipe 8 is located, the contact wheel 705 first contacts the steel pipe 8, and then the welding head 702 approaches the circumferential seam.

[0042] In Example 2, based on Example 1, when the two steel pipes 8 are fixed on the two clamping seats 2 respectively, the positioning blind plate 601 of the positioning frame 6 is at the joint of the two steel pipes 8. The piston rod of the welding cylinder 401 is pushed out, the connecting block 402 moves, and the positioning frame 6 and the welding frame 7 move synchronously. The positioning blind plate 601 is withdrawn from between the two steel pipes 8. At the same time, under the action of the alignment spring 2032, the sliding clamping seat 2 moves, and the steel pipe 8 on it moves closer to the other steel pipe 8 in the fixed state and joins with it. The circumferential seam of the joint is directly opposite the welding head 702, the contact wheel 705 abuts against the wall of the steel pipe 8, and the welding head 702 welds the circumferential seam.

[0043] The following provides further explanation and elaboration on the structural and technical features mentioned above:

[0044] The welding base 1 serves as the main support of the device, and the clamping seats 2 at both ends constitute the steel pipe 8 clamping system. The fixed clamping seat 2 provides a stable reference end, while the sliding clamping seat 2 achieves horizontal displacement adjustment through a sliding fit between its bottom and the top of the welding base 1. A directional guide rod 203 on the sliding clamping seat 2 passes through the fixed clamping seat 2, and its end plug 2031 and alignment spring 2032 form an elastic reset mechanism, providing buffer compensation during the steel pipe 8 docking process to ensure balanced pressure when the two steel pipe 8 end faces contact. The double-ended lead screw 201 is driven to rotate by a synchronous motor 202, causing the symmetrically arranged clamping blocks 3 to move synchronously in opposite directions under the guidance of the T-rail. A four-point clamping structure is formed by the upper and lower clamping rollers 301 (the rotating motor 302 drives one of the clamping rollers 301 via a belt), which not only achieves stable clamping of the steel pipe 8 but also drives the steel pipe 8 to rotate around its axis by driving the clamping rollers 301, providing a uniform motion basis for circumferential welding.

[0045] The positioning frame 6 and welding frame 7 form a linkage mechanism through the connecting block 402, and the welding cylinder 401 has timing control characteristics when driven. The fan-shaped plate of the positioning blind plate 601 is initially embedded in the gap between the two steel pipes 8, achieving pre-positioning through the contact of its circumferential edge with the outer wall of the steel pipe 8. When the welding cylinder 401 pushes the connecting block 402, the retraction action of the positioning frame 6 and the elastic advancement of the sliding clamping seat 2 are coordinated in a timing sequence: the alignment spring 2032 releases its elastic force to push the sliding clamping seat 2 towards the fixed end, while the positioning blind plate 601 exits the docking area, allowing the end face of the steel pipe 8 to be precisely aligned to form a welding circumferential seam. During this process, the contact wheel 705 of the welding frame 7 achieves adaptive clamping through the buffer rod 704 and the buffer spring 706. The contact wheel 705 contacts the surface of the steel pipe 8 before the welding head 702, forming a buffer support. The welding head 702 on the welding cantilever 701 then precisely aligns with the circumferential seam to complete the welding operation. The support plate 204 serves as the bottom support structure for the steel pipe 8, providing temporary support before the clamping action and reducing the difficulty of manual positioning. The entire device achieves fully automated operation of the steel pipe 8 welding process through mechanical linkage and electrical control coordination.

[0046] Working principle:

[0047] The operator places two steel pipes 8 to be welded onto the arc-shaped support plates 204 of the two clamping seats 2, respectively. The support plates 204 provide temporary support for the steel pipes 8 to reduce the difficulty of manual positioning. Subsequently, the synchronous motor 202 drives the double-ended lead screw 201 to rotate, which drives the two clamping blocks 3 to move synchronously in opposite directions along the T-rail through the reverse thread. The clamping rollers 301 at the upper and lower ends of the clamping blocks 3 cover the steel pipes 8 from four directions to form a four-point clamping structure. At this time, the rotary motor 302 drives one of the clamping rollers 301 to rotate through the belt, so that the steel pipe 8 can rotate around its own axis in the clamped state.

[0048] After the initial fixing of the steel pipes 8 is completed, the positioning blind plate 601 of the positioning frame 6 is embedded in the gap between the two steel pipes 8, and its fan-shaped plate is tightly attached to the outer wall of the steel pipes 8, realizing radial pre-positioning before welding. The controller 5 starts the welding cylinder 401, and the piston rod pushes the connecting block 402 to move towards the steel pipe 8, causing the positioning frame 6 and the welding frame 7 to move synchronously. The positioning blind plate 601 is removed from between the two steel pipes 8, and at the same time, the sliding clamping seat 2 slides along the guide rod 203 towards the fixed clamping seat 2 under the elastic force of the positioning spring 2032, so that the end faces of the two steel pipes 8 accurately abut to form an annular seam. During this process, the elastic reset mechanism limits the displacement of the sliding clamping seat 2 through the plug 2031 to ensure balanced docking pressure.

[0049] As the welding frame 7 moves with the connecting block 402, the buffer rod 704 of the contact seat 703, under the action of the buffer spring 706, pushes the contact wheel 705 to contact the surface of the steel pipe 8 first, forming an adaptive clamping structure. When the welding head 702 of the welding cantilever 701 is aligned with the circumferential seam, the rotary motor 302 drives the steel pipe 8 to rotate at a constant speed, and the welding head 702 performs continuous welding along the circumferential seam trajectory. During the rotation of the steel pipe 8, the contact wheel 705 offsets mechanical vibration through rolling friction, and the buffer spring 706 absorbs axial deviation during the welding process, ensuring that the welding head 702 always maintains a stable distance from the circumferential seam. After welding is completed, the synchronous motor 202 reverses to release the clamping block 3, the operator removes the weldment, and the device resets under the action of the alignment spring 2032, completing the fully automated welding operation.

[0050] The following points should be noted in this article:

[0051] 1. The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention; other structures can refer to general designs.

[0052] 2. Where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other to obtain new embodiments.

[0053] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An auxiliary welding device for steel pipes used in construction, comprising: Welding base (1); characterized in that, clamping seats (2) are respectively provided at both ends of the welding base (1), one clamping seat (2) is fixedly connected to the welding base (1), and the lower end of the other clamping seat (2) is slidably tangent to the top of the welding base (1). Two directional guide rods (203) are vertically provided on the sliding clamping seat (2) facing the fixed clamping seat (2). The end of the directional guide rod (203) passes through the fixed clamping seat (2). A plug (2031) is provided at the end of the directional guide rod (203). A positioning spring (2032) is fitted on the directional guide rod (203) between the plug (2031) and the fixed clamping seat (2). The clamping seat (2) slides symmetrically. A clamping block (3) is provided, and two clamping blocks (3) move in opposite directions to clamp the steel pipe (8). The clamping blocks (3) on the two clamping seats (2) respectively clamp two steel pipes (8) that are connected to each other. A welding frame (4) is longitudinally fixedly installed on the welding base (1) between the two clamping seats (2). A controller (5) is fixedly installed at the front end of the welding frame (4). A welding cylinder (401) is fixedly installed at one end of the top of the welding frame (4). A connecting block (402) is fixedly connected to the end of the piston rod of the welding cylinder (401). The connecting block (402) is always slidably tangential to the upper end of the welding frame (4). A welding frame (7) is fixedly installed at one end of the connecting block (402), and a positioning frame (6) is fixedly installed at the other end. A double-ended screw (201) is rotatably installed between the top two ends of the clamping seat (2). Two clamping blocks (3) are respectively vertically screwed onto the opposite thread of the double-ended screw (201). The lower end of the clamping block (3) is slidably engaged with the T-rail fixedly provided at the upper end of the clamping seat (2). A synchronous motor (202) is fixedly provided at one end of the clamping seat (2). The synchronous motor (202) is used to drive the double-ended screw (201) to rotate. The rotation of the double-ended screw (201) drives the two clamping blocks (3) to move synchronously in opposite directions to clamp the steel pipe (8) and to move synchronously in opposite directions to release the steel pipe (8). Both clamping seats (2) have an arc-shaped support plate (204) fixed at the middle of their opposite ends, and the lower end of the steel pipe (8) to be welded is supported on the support plate (204). The upper and lower ends of the two opposing clamping blocks (3) are respectively rotatably mounted with clamping rollers (301), and the clamped steel pipe (8) is located between the four clamping rollers (301). A rotary motor (302) is fixedly mounted on the clamping block (3) at one of the clamping rollers (301). The rotating shaft of the rotary motor (302) is connected to the end rotating shaft of the adjacent clamping roller (301) by a belt. When the rotary motor (302) works, it drives the clamping roller (301). The clamping roller (301) drives the steel pipe (8) in the clamping state to rotate and cooperate with the circumferential weld. The upper end of the positioning frame (6) is fixedly provided with a positioning blind plate (601) facing the joint of the two steel pipes (8), and the circumferential edge of the positioning blind plate (601) is provided with a fan-shaped patch attached to the outer wall of the two steel pipes (8). The upper end of the welding frame (7) is fixedly provided with a welding cantilever (701) horizontally facing the welding point. The welding head (702) is fixedly provided at one end of the welding cantilever (701) facing the welding point. A contact seat (703) is fixedly provided on the welding cantilever (701). Two symmetrical buffer rods (704) are vertically slidably provided at the upper and lower ends of the contact seat (703). A contact wheel (705) is rotatably connected between the ends of each set of buffer rods (704). The contact wheel (705) is close to the steel pipe (8). A buffer spring (706) is fitted on the buffer rod (704). When the welding frame (7) moves with the connecting block (402) to the side where the steel pipe (8) is located, the contact wheel (705) first contacts the steel pipe (8), and then the welding head (702) approaches the circumferential seam. When the two steel pipes (8) are fixed on the two clamping seats (2) respectively, the positioning blind plate (601) of the positioning frame (6) is at the joint of the two steel pipes (8), the piston rod of the welding cylinder (401) is pushed out, the connecting block (402) moves, the positioning frame (6) and the welding frame (7) move synchronously, the positioning blind plate (601) is removed from between the two steel pipes (8), and at the same time, under the action of the positioning spring (2032), the sliding clamping seat (2) moves, the steel pipe (8) on it moves closer to the other steel pipe (8) in the fixed state and joins, the circumferential seam of the joint is directly opposite the welding head (702), the contact wheel (705) abuts against the wall of the steel pipe (8), and the welding head (702) performs welding of the circumferential seam.

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