Plasma spray welding device for steel structures

Abstract

The application relates to the technical field of spray welding, and discloses a plasma spray welding device for steel structures, which comprises a spray welding machine body, the top of the spray welding machine body is provided with an electric sliding rail, the top of the electric sliding rail is provided with an L-shaped back plate, a spray gun head is arranged on the L-shaped back plate, two vertical seats are symmetrically arranged on the top of the spray welding machine body, an inner ring is arranged on the inner side of each vertical seat, and a variable clamping retreat unit is arranged on the inner side of the inner ring. The plasma spray welding device for steel structures is provided with a double-clamping-plate variable clamping structure which can be opened and closed in linkage, only needs to drive the central plate to slide, can quickly switch between the plane clamping and V-shaped clamping modes, and can simultaneously adapt to two types of steel structure workpieces, i.e. square tubes and round tubes, of a single set of clamps. The clamps do not need to be frequently disassembled and replaced for different section pipes, the auxiliary working hours for workpiece changing are greatly shortened, the processing efficiency of batch spray welding is significantly improved, and the problems of clamp positioning reference wear and locking part loosening caused by repeated disassembly and assembly are avoided.

Description

Technical Field

[0001] This invention relates to the field of spray welding technology, and more particularly to a plasma spray welding apparatus for steel structures. Background Technology

[0002] Spray welding machines use electric arcs or plasma as a heat source to instantly melt metal wires or powders. The molten droplets are then atomized into fine particles by a high-pressure gas stream and sprayed at high speed to impact the workpiece surface. The high temperature of the droplets simultaneously melts micro-areas on the workpiece surface, forming a dense, metallurgically bonded weld layer. This layer combines the coverage of spray coatings with the strength of fusion welding and is often used for wear-resistant and corrosion-resistant applications, as well as parts repair. However, existing spray welding machines still have the following drawbacks: Currently, commercially available plasma spraying clamps have poor versatility. Their structures are mostly designed for single-section adaptation; dedicated square tube clamps can only clamp square tubes, and round tube clamps can only accommodate round tubes, making the two types of clamps incompatible. In batch plasma spraying operations on steel structures, square and round tubes are frequently interchanged during workpiece processing. Operators need to repeatedly disassemble and replace the entire clamping set, making the process cumbersome and significantly increasing the time spent loading and unloading individual workpieces, directly reducing overall welding efficiency. Frequent disassembly and replacement of clamps also introduces assembly hazards. After repeated disassembly and assembly, the clamping reference and locking bolts are prone to insufficient preload and increased positioning gaps. Insufficient clamping force during subsequent tube clamping can lead to workpiece misalignment and wobbling during welding, resulting in uncontrolled weld alignment accuracy, substandard forming quality, and a significant increase in defective products such as misaligned workpieces and uneven weld layer thickness, increasing material waste and rework time. In addition, existing fixtures employ a rigid locking positioning structure, where all clamping blocks are completely fixed in position with no buffering margin after clamping. Plasma spraying operations involve extremely high temperatures, and the tubular workpiece continuously absorbs a large amount of heat. Based on the thermal expansion and contraction characteristics of metals, the tube wall will undergo radial expansion after being heated. However, the fixture has no room for retraction, and the continuous rigid constraint on the expanding tube wall prevents the release of the compressive force generated by the expansion. This stress concentration acts on the tube body, easily causing permanent deformations such as corner dents in square tubes and flattening and twisting of round tubes, directly resulting in workpiece scrap, increasing production losses, and failing to guarantee the dimensional accuracy of the finished steel structure, making it difficult to meet the requirements of high-standard spraying processing. Summary of the Invention

[0003] Given the poor versatility of existing fixtures, which can only accommodate workpieces of one shape, resulting in reduced welding efficiency, and the lack of clearance space in existing fixtures, which can easily cause workpiece deformation due to thermal expansion during welding, a plasma spraying welding device for steel structures is proposed.

[0004] This application provides a plasma spraying welding device for steel structures, the purpose of which is to improve the versatility of the fixture, thereby increasing the welding efficiency. At the same time, the fixture has a retraction space, which allows the fixture to retract when the workpiece is thermally expanded, providing space for the workpiece to expand and making the workpiece less prone to deformation.

[0005] The technical solution of the present invention is as follows: a plasma spraying welding device for steel structures, including a spraying welding machine body, an electric slide rail on the top of the spraying welding machine body, an L-shaped rear plate on the top of the electric slide rail, a spray gun head on the L-shaped rear plate, two uprights symmetrically distributed on the top of the spraying welding machine body, an inner ring on the inner side of the uprights, a square tube on the inner side of the inner ring, and a variable clamping retraction unit disposed on the inner side of the inner ring; The variable clamp retraction unit includes a variable clamp component disposed on the inner side of the inner ring, a retraction component disposed on the variable clamp component, and a variable clamp assembly disposed on the inner side of the inner ring, and a deformation component disposed on the variable clamp assembly. The variable clamping component is used to clamp steel of different shapes, and the retraction component allows the clamp to move away from the steel when the steel expands due to welding heat. The variable clamp assembly includes several first electric actuators arranged in a ring array on the inner side of the inner ring. A U-shaped plate is provided at the output end of the first electric actuator, a central plate is provided on the inner side of the U-shaped plate, a first clamping plate is provided at one end of the central plate, and a second clamping plate is provided at the other end of the central plate. The first clamping plate and the second clamping plate are respectively movably connected to the two ends of the U-shaped plate.

[0006] Furthermore, the variable clamp assembly also includes a second electric actuator disposed on the U-shaped plate, the output end of which is fixedly connected to the center plate.

[0007] Furthermore, the deformation component includes two symmetrically distributed deformation grooves disposed on the first clamping plate and the second clamping plate, and a deformation block is disposed inside the deformation groove, the deformation block being fixedly connected to the U-shaped plate.

[0008] Furthermore, the retraction component includes a retraction component, a pull-up component, a rotation component, and a thermal expansion component disposed on the variable clamp assembly; The retraction assembly includes a retraction rod disposed at the output end of the first electric push rod. A cavity is provided on the retraction rod, and a retraction block is disposed inside the cavity. A retraction spring is disposed between the retraction block and the inside of the cavity. The retraction spring is sleeved on the retraction block, and the retraction block is fixedly connected to the U-shaped plate.

[0009] Furthermore, the yielding block has a T-shaped structure.

[0010] Furthermore, the pull-up assembly includes a pull-up cylinder disposed inside the cavity, and a pull-up column is disposed on the pull-up cylinder, the pull-up column being fixedly connected to the retraction block.

[0011] Furthermore, the rotating assembly includes a trigger rod disposed on the retraction rod, the trigger rod having a protrusion, and the upper pull cylinder having an arc-shaped groove, the protrusion being slidably connected to the inner side of the arc-shaped groove.

[0012] Furthermore, the thermal expansion assembly includes an opening on the second clamping plate, a heat-conducting plate inside the opening, a heat-conducting telescopic rod on the heat-conducting plate, carbon steel on the U-shaped plate, a fixed connection between the end of the heat-conducting telescopic rod away from the heat-conducting plate and the carbon steel, and a trigger rod fixedly connected to the carbon steel.

[0013] The beneficial effects of this invention are: The interlocking double-clamp structure allows for quick switching between planar and V-shaped clamping modes simply by driving the center plate to slide. A single clamp can accommodate both square and round steel workpieces. This eliminates the need for frequent clamping changes for different pipe cross-sections, significantly reducing auxiliary time for workpiece changeovers and dramatically improving batch welding efficiency. It also avoids wear on the clamping reference and loosening of locking components caused by repeated disassembly and assembly, maintaining stable clamping and alignment accuracy even after long-term use. This effectively reduces defects such as weld misalignment and uneven weld layers caused by clamping deviations, while also reducing the costs of purchasing, storing, and maintaining multiple spare clamps.

[0014] The elastic retraction structure allows the grippers to retract slightly radially during the thermal expansion of the workpiece during welding, releasing the deformation space required for the pipe wall's thermal expansion. This completely avoids permanent deformations such as dents and twists caused by thermal expansion under rigid clamping. The retraction process relies on the spring preload to provide a stable clamping force, preventing workpiece loosening and displacement. This ensures positioning accuracy during welding and eliminates damage to the workpiece caused by thermal stress concentration. This structure effectively reduces the scrap rate of thin-walled pipe welding and minimizes rework, making it particularly suitable for plasma welding scenarios with large temperature differences and long processing times.

[0015] The heat from the workpiece is conducted to the thermal expansion drive component via a heat-conducting component. The retraction action is automatically triggered by the thermal expansion characteristics of metal, eliminating the need for additional temperature sensors, electronic control components, or other electrical devices. The triggering timing is matched to the workpiece temperature rise in real time, ensuring precise and delay-free response and avoiding errors from manual parameter adjustments and the risk of electronic control component failure. The overall structure requires no external power or control wiring, boasts high integration, low modification costs, and easy integration into existing spray welding equipment. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic cross-sectional view of the support structure of the present invention; Figure 3 This is a cross-sectional view of the variable clamping retraction unit of the present invention; Figure 4 This is a schematic diagram of the variable clamp component structure of the present invention; Figure 5 This is a schematic diagram of the deformable structure of the variable clamping retraction unit of the present invention; Figure 6 This is an exploded view of the deformable component of the present invention; Figure 7 This is an exploded view of the thermal expansion component of the present invention; Figure 8 This is a schematic cross-sectional view of the yielding component of the present invention; Figure 9 This is an exploded view of the rotating component of the present invention; Figure 10 This is a schematic diagram of the pull-up component structure of the present invention.

[0017] In the picture: 1. Welding machine body; 11. Electric slide rail; 12. L-shaped rear plate; 13. Spray gun head; 14. Stand; 15. Inner ring; 16. Square tube; 2. Variable clamp assembly; 21. First electric push rod; 22. U-shaped plate; 23. Second electric push rod; 24. Center plate; 25. First clamping plate; 26. Second clamping plate; 3. Deformation assembly; 31. Deformation groove; 32. Deformation block; 4. Retreat assembly; 41. Retreat rod; 42. Retreat block; 43. Retreat spring; 5. Pull-up assembly; 51. Pull-up cylinder; 52. Pull-up column; 6. Rotation assembly; 61. Trigger rod; 62. Protrusion; 63. Arc groove; 7. Thermal expansion assembly; 71. Opening; 72. Heat-conducting plate; 73. Heat-conducting telescopic rod; 74. Carbon steel. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Example 1, referring to Figures 1-6This invention provides a plasma spraying device for steel structures, comprising a spraying machine body 1, an electric slide rail 11 fixedly connected to the top of the spraying machine body 1, an L-shaped rear plate 12 slidably connected to the top of the electric slide rail 11, a spray gun head 13 slidably connected to the L-shaped rear plate 12, two uprights 14 symmetrically distributed and fixedly connected to the top of the spraying machine body 1, an inner ring 15 rotatably connected to the inner side of the uprights 14, a square tube 16 inserted into the inner side of the inner ring 15, and a variable clamp retraction unit installed inside the inner ring 15; the variable clamp retraction unit includes a variable clamp component installed inside the inner ring 15, and a retraction component installed on the variable clamp component, the variable clamp component including... A variable clamp assembly 2 is installed inside the inner ring 15, and a deformable component 3 is installed on the variable clamp assembly 2. The variable clamp component is used to clamp steel of different shapes, and the retraction component allows the clamp to move away from the steel when the steel expands due to welding. The variable clamp assembly 2 includes a number of first electric push rods 21 that are fixedly connected to the inner ring 15 in a ring array. The output end of the first electric push rod 21 is slidably connected to a U-shaped plate 22. A center plate 24 is slidably connected to the inner side of the U-shaped plate 22. A first clamping plate 25 is hinged to one end of the center plate 24, and a second clamping plate 26 is hinged to the other end of the center plate 24. The first clamping plate 25 and the second clamping plate 26 are respectively movably connected to the two ends of the U-shaped plate 22.

[0020] Specifically, the square tube 16 to be welded is inserted into the inner ring 15, and several first electric actuators 21 are simultaneously activated, causing the U-shaped plate 22 to move towards one side of the square tube 16, so that the center plate 24, the first clamping plate 25, and the second clamping plate 26 are attached to the wall of the square tube 16. The several first clamping plates 25 and the second clamping plates 26 clamp the square tube 16 from different directions, thus fixing the square tube 16. When welding a round tube is required, the center plate 24 is controlled to slide inside the U-shaped plate 22, causing the first clamping plates 25 and the second clamping plates 26 to rotate on the center plate 24, so that the first clamping plates 25 and the second clamping plates 26 rotate and slide on the U-shaped plate 22, so that a V-shaped structure is formed between the first clamping plates 25 and the second clamping plates 26. At this time, the first clamping plates 25 and the second clamping plates 26 can clamp the round tube. Then, the round tube is inserted into the inner side of the inner ring 15, and several first electric actuators 21 are activated in the same way, so that the first clamping plates 25 and the second clamping plates 26 clamp and fix the round tube. One set of fixtures is compatible with both square tubes 16 and round tubes, eliminating the need for frequent changes and significantly improving workpiece changeover processing efficiency; it reduces disassembly and assembly wear, prevents fixture loosening and displacement, stabilizes clamping accuracy, reduces defect rates, and simultaneously reduces the procurement and management costs of spare fixtures. A toothed ring is fitted on the inner ring 15, and an external motor with gears is installed on the stand 14. The gears mesh with the toothed ring. Starting the external motor, through the toothed ring and gears, drives the inner ring 15 to rotate, thereby rotating the square tube 16 or round tube. The electric slide rail 11 can move the L-shaped back plate 12 left and right, allowing adjustment of the left and right position of the spray gun head 13. The spray gun head 13 slides up and down on the L-shaped back plate 12, adjusting its vertical position so that it can precisely weld the square tube 16 or round tube to the desired welding position.

[0021] Reference Figure 4 and Figure 5 The variable clamp assembly 2 also includes a second electric actuator 23 fixedly connected to the U-shaped plate 22, and the output end of the second electric actuator 23 is fixedly connected to the center plate 24.

[0022] Specifically, when the clamping assembly 2 needs to be adjusted, the second electric actuator 23 is activated, causing the center plate 24 to move closer to the U-shaped plate 22, forming a V-shaped structure between the first clamping plate 25 and the second clamping plate 26, which facilitates clamping the round tube. When the square tube 16 needs to be clamped, the second electric actuator 23 is activated, causing the center plate 24 to move away from the U-shaped plate 22, so that the center lines of the first clamping plate 25 and the second clamping plate 26 coincide. The center plate 24 is provided with a convex baffle. When the center plate 24 is pushed to move, the convex baffle blocks and limits the first clamping plate 25 and the second clamping plate 26, preventing them from rotating excessively and causing their center lines to intersect.

[0023] Reference Figure 5 and Figure 6The deformation component 3 includes two symmetrically distributed deformation grooves 31 formed on the first clamping plate 25 and the second clamping plate 26. Deformation blocks 32 are movably connected to the inner side of the deformation grooves 31, and the deformation blocks 32 are fixedly connected to the U-shaped plate 22.

[0024] Specifically, when the first clamping plate 25 and the second clamping plate 26 rotate, the deformation block 32 slides and rotates inside the deformation groove 31, so that when the first clamping plate 25 and the second clamping plate 26 rotate on the center plate 24, they never detach from the U-shaped plate 22. At the same time, it is also convenient to adjust the first clamping plate 25 and the second clamping plate 26 into a V-shaped structure.

[0025] Example 2, refer to Figures 7-10 This is the second embodiment of the present invention, which differs from the first embodiment in that: the retraction component includes a retraction component 4, an upward pull component 5, a rotation component 6, and a thermal expansion component 7 mounted on the variable clamp assembly 2; the retraction component 4 includes a retraction rod 41 fixedly connected to the output end of the first electric push rod 21, a cavity is provided on the retraction rod 41, a retraction block 42 is slidably connected to the inner side of the cavity, a retraction spring 43 is fixedly connected between the retraction block 42 and the inner side of the cavity, the retraction spring 43 is sleeved on the retraction block 42, and the retraction block 42 is fixedly connected to the U-shaped plate 22.

[0026] Specifically, initially, the release spring 43 causes the compressed pull-up assembly 5 to block the release block 42, making the release block 42 rigidly connected to the release rod 41, thus fixing the clamping assembly 2 to the first electric push rod 21. When the pull-up assembly 5 is triggered, it releases the rigid connection to the release block 42, and the release spring 43 returns to its original position, causing the release block 42 to slide inward into the cavity, moving the U-shaped plate 22. This causes a slight movement of the clamping assembly 2, which, during welding, allows the workpiece to expand on the clamp due to thermal expansion. This slight movement of the clamping assembly 2 buffers the thermal expansion of the workpiece. It can fully absorb the thermal expansion during the welding process, preventing permanent deformation of the pipe wall due to rigid constraint and compression; at the same time, it maintains a stable clamping force, ensuring welding positioning accuracy and effectively reducing workpiece scrap rate and rework costs.

[0027] Reference Figure 8 The yield block 42 has a T-shaped structure.

[0028] Specifically, the T-shaped relief block 42 allows the relief spring 43 to act on the relief block 42, causing the relief block 42 to move without sliding out of the cavity.

[0029] Reference Figure 8 and Figure 10 The pull-up assembly 5 includes a pull-up cylinder 51 rotatably connected to the inside of the cavity, and a pull-up column 52 threadedly connected to the pull-up cylinder 51. The pull-up column 52 is fixedly connected to the relief block 42.

[0030] Specifically, when the upper pull cylinder 51 rotates, the threaded connection between the upper pull cylinder 51 and the upper pull column 52 causes the upper pull column 52 to move upward inside the upper pull cylinder 51, driving the relief block 42 to move. When the upper pull cylinder 51 does not rotate, it limits the upper pull column 52, thus fixing the relief block 42 to the relief rod 41, facilitating the clamping and fixing of the workpiece. The remaining structure is the same as that in Embodiment 1.

[0031] Example 3, referring to Figure 8 and Figure 9 This is the third embodiment of the present invention. The difference between this embodiment and the second embodiment is that the rotating component 6 includes a trigger rod 61 that is slidably connected to the retraction rod 41. A protrusion 62 is fixedly connected to the trigger rod 61. An arc-shaped groove 63 is provided on the upper pull cylinder 51. The protrusion 62 is slidably connected to the inner side of the arc-shaped groove 63.

[0032] Specifically, when the trigger rod 61 slides upward on the retracting rod 41, the protrusion 62 slides inside the arc groove 63. Under the action of the arc groove 63, the upper pull cylinder 51 rotates, causing the upper pull column 52 to move upward. When the trigger rod 61 slides downward on the retracting rod 41, the upper pull cylinder 51 rotates in the opposite direction, causing the upper pull column 52 to move downward.

[0033] Reference Figure 7 and Figure 8 The thermal expansion component 7 includes an opening 71 on the second clamping plate 26, a heat-conducting plate 72 slidably connected to the inside of the opening 71, a heat-conducting telescopic rod 73 hinged to the heat-conducting plate 72, a carbon steel 74 fixedly connected to the U-shaped plate 22, a heat-conducting telescopic rod 73 at the end away from the heat-conducting plate 72 fixedly connected to the carbon steel 74, and a trigger rod 61 fixedly connected to the carbon steel 74.

[0034] Specifically, when the second clamping plate 26 is attached to the workpiece, the heat-conducting plate 72 will also be attached to the workpiece. During welding, heat is generated and conducted through the heat-conducting plate 72 to the heat-conducting telescopic rod 73. The heat-conducting telescopic rod 73 consists of a telescopic outer cylinder and a telescopic inner rod, which are slidably connected to the telescopic outer cylinder. Heat is conducted through the heat-conducting telescopic rod 73 to the carbon steel 74, causing the carbon steel 74 to expand and move the trigger rod 61. When the variable clamping assembly 2 deforms, the heat-conducting plate 72 can slide inside the opening 71, and the heat-conducting telescopic rod 73 can extend and retract, ensuring that the second clamping plate 26 is not obstructed or interfered with during rotation. Simultaneously, after the variable clamping assembly 2 deforms, the thermal expansion assembly 7 can still conduct heat, causing the carbon steel 74 to expand. The remaining structure is the same as in Embodiment 2.

[0035] Based on embodiments 1-3, the working principle of the present invention is as follows: When welding the square tube 16, the second electric actuator 23 is activated to adjust the first clamping plate 25 and the second clamping plate 26 to a horizontal state, and the square tube 16 is inserted into the inner ring 15. Then, the first electric actuator 21 is activated to move the first clamping plate 25 and the second clamping plate 26 to one side of the square tube 16 to clamp it. When it is necessary to clamp the round tube, the second electric actuator 23 is activated to adjust the first clamping plate 25 and the second clamping plate 26 into a V-shaped structure, and the round tube is inserted into the inner ring 15 to clamp it. When welding the workpiece, the workpiece will be heated during the welding process. Since the heat-conducting plate 72 is in contact with the workpiece, the heat is transferred to the heat-conducting plate 72 and then to the carbon steel 74 through the heat-conducting telescopic rod 73. The carbon steel 74 expands due to heat, which drives the trigger rod 61 to move, causing the protrusion 62 to slide inside the arc groove 63. Under the action of the arc groove 63, the upper pull cylinder 51 rotates. Since the upper pull cylinder 51 and the upper pull column 52 are threadedly connected, the upper pull column 52 moves upward. Under the action of the relief spring 43, the relief block 42 moves towards the inside of the cavity, which drives the U-shaped plate 22 to move. This causes the first clamping plate 25 and the second clamping plate 26 to move slightly away from the workpiece, so that there is a buffer space when the workpiece expands, preventing the workpiece from being damaged by the clamp during expansion.

[0036] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A plasma spraying welding device for steel structures, comprising a welding machine body (1), an electric slide rail (11) on the top of the welding machine body (1), an L-shaped rear plate (12) on the top of the electric slide rail (11), a spray gun head (13) on the L-shaped rear plate (12), and two uprights (14) symmetrically distributed on the top of the welding machine body (1), an inner ring (15) on the inner side of the uprights (14), and a square tube (16) on the inner side of the inner ring (15), characterized in that: It also includes a variable clamping retraction unit located inside the inner ring (15); The variable clamp retraction unit includes a variable clamp component disposed on the inner side of the inner ring (15), and a retraction component is disposed on the variable clamp component. The variable clamp component includes a variable clamp assembly (2) disposed on the inner side of the inner ring (15), and a deformation assembly (3) is disposed on the variable clamp assembly (2). The variable clamping component is used to clamp steel of different shapes, and the retraction component allows the clamp to move away from the steel when the steel expands due to welding heat. The variable clamp assembly (2) includes several first electric actuators (21) arranged in a ring array inside the inner ring (15). The output end of the first electric actuator (21) is provided with a U-shaped plate (22). The inner side of the U-shaped plate (22) is provided with a center plate (24). One end of the center plate (24) is provided with a first clamping plate (25), and the other end of the center plate (24) is provided with a second clamping plate (26). The first clamping plate (25) and the second clamping plate (26) are respectively movably connected to both ends of the U-shaped plate (22).

2. The plasma spraying apparatus for steel structures according to claim 1, characterized in that: The variable clamp assembly (2) also includes a second electric push rod (23) disposed on the U-shaped plate (22), and the output end of the second electric push rod (23) is fixedly connected to the center plate (24).

3. The plasma spraying apparatus for steel structures according to claim 1, characterized in that: The deformation component (3) includes two symmetrically distributed deformation grooves (31) on the first clamping plate (25) and the second clamping plate (26). A deformation block (32) is provided inside the deformation groove (31), and the deformation block (32) is fixedly connected to the U-shaped plate (22).

4. The plasma spraying apparatus for steel structures according to claim 1, characterized in that: The retraction component includes a retraction component (4), an upward component (5), a rotation component (6), and a thermal expansion component (7) disposed on the variable clamp assembly (2). The retraction component (4) includes a retraction rod (41) disposed at the output end of the first electric push rod (21). A cavity is provided on the retraction rod (41), and a retraction block (42) is disposed inside the cavity. A retraction spring (43) is disposed between the retraction block (42) and the inside of the cavity. The retraction spring (43) is sleeved on the retraction block (42), and the retraction block (42) is fixedly connected to the U-shaped plate (22).

5. The plasma spraying apparatus for steel structures according to claim 4, characterized in that: The yield block (42) has a T-shaped structure.

6. The plasma spraying apparatus for steel structures according to claim 4, characterized in that: The pull-up assembly (5) includes a pull-up cylinder (51) disposed inside the cavity, and a pull-up column (52) is disposed on the pull-up cylinder (51). The pull-up column (52) is fixedly connected to the push-back block (42).

7. The plasma spraying apparatus for steel structures according to claim 6, characterized in that: The rotating assembly (6) includes a trigger rod (61) disposed on the retraction rod (41), a protrusion (62) disposed on the trigger rod (61), and an arc groove (63) disposed on the upper pull cylinder (51), the protrusion (62) and the inner side of the arc groove (63) being slidably connected.

8. The plasma spraying apparatus for steel structures according to claim 7, characterized in that: The thermal expansion assembly (7) includes an opening (71) on the second clamping plate (26), a heat-conducting plate (72) is provided inside the opening (71), a heat-conducting telescopic rod (73) is provided on the heat-conducting plate (72), carbon steel (74) is provided on the U-shaped plate (22), the end of the heat-conducting telescopic rod (73) away from the heat-conducting plate (72) is fixedly connected to the carbon steel (74), and the trigger rod (61) is fixedly connected to the carbon steel (74).

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