Duplex stainless steel welding device and using method

Abstract

The invention relates to the technical field of duplex stainless steel welding, in particular to a duplex stainless steel welding device and a use method.The duplex stainless steel welding device comprises an operation table, a positioning mechanism and a plugging mechanism, a welding arm is fixedly arranged on the operation table, a welding gun is connected to the end of the welding arm, and a workpiece is placed on the operation table; a supporting block I and a supporting block II of the positioning mechanism synchronously move, are stable and do not deviate, so that the axis of the workpiece is centered, and the workpiece can be quickly positioned; the blocking mechanism is in linkage with the second air bag through the push rod to expand synchronously and is matched with the first air bag to achieve double blocking of the two ends of the workpiece, the welding auxiliary gas leakage amount is greatly reduced, gas consumption is saved, and production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of duplex stainless steel welding, in particular to a duplex stainless steel welding device and a use method thereof. Background Art

[0002] Duplex stainless steel is composed of two phases, austenite and ferrite. This structure gives it superior strength and corrosion resistance compared to ordinary austenitic stainless steel. These properties make it widely used in fields such as chemical engineering, marine engineering, and oil and gas. Structural components and equipment in these fields require welding to connect components and complete the structure. For example, welding is an unavoidable process in pipe connection and container manufacturing.

[0003] Some pipe connections require elbows to achieve diversion and conveying requirements. During welding, auxiliary gas (such as argon or helium) must be introduced into the welded workpiece to mitigate air intrusion, process instability, and compositional segregation. Due to the curved shape of the elbow, single-end alignment is often used when connecting the two workpieces. This can cause workpiece skew and axis deviation, affecting pipe alignment and potentially misaligning during welding, resulting in poor weld quality. Furthermore, workpiece misalignment can lead to gas leakage during gas filling. This prevents the weld area from being fully shielded by the shielding gas, causing oxygen and nitrogen to react with the high-temperature molten pool to form oxides or nitrides, resulting in a black or bluish discoloration of the weld surface. This damages the passive film on the duplex stainless steel surface and significantly reduces corrosion resistance. Oxide particles can become trapped as inclusions, degrading the weld's mechanical properties and potentially inducing crack propagation, particularly under pressure or alternating loads. Summary of the Invention

[0004] The object of the present invention is to provide a duplex stainless steel welding device and a method for use thereof to solve the problems raised by the above background technology.

[0005] The technical solution adopted by the present application to solve the technical problem is: a duplex stainless steel welding device, comprising: an operating table, a welding arm fixedly provided on the operating table, a welding gun connected to the end of the welding arm, a workpiece placed on the operating table, and further comprising: A positioning mechanism is provided on an operating table, comprising a guide rail 1 symmetrically and fixedly provided on the operating table, wherein each guide rail is slidably connected to a slider, and each slider is fixedly connected to a support block 1, and the positioning mechanism is used to quickly position a workpiece; The blocking mechanism is arranged on the positioning mechanism, and the blocking mechanism includes airbag 1 and airbag 2 arranged on the inner walls of both ends of the workpiece. The blocking mechanism is used to block the two ends of the workpiece.

[0006] Preferably, an L-shaped rod is fixedly provided on one side of the slider, a fixed block is fixedly provided on one end of the L-shaped rod away from the slider, and a second supporting block is fixedly provided on the fixed block.

[0007] Preferably, a disc is provided between the two support blocks, a slide groove is symmetrically provided on the disc, a sliding rod is slidably provided in the slide groove, and the end of the sliding rod is fixedly connected to the inner wall of the two support blocks.

[0008] Preferably, the positioning mechanism also includes a guide rail 2 and a support block fixedly arranged on the operating table, the top of the support block is set as an arc surface, the guide rail 2 is set between the guide rail 1, and a drive shaft is rotatably connected through the middle of the guide rail 2, and the drive shaft is connected to an external drive.

[0009] Preferably, a connecting disk is fixedly connected to the driving shaft, an 8-shaped groove is provided on the connecting disk, a roller is symmetrically slidably connected to the inner wall of the 8-shaped groove, a connecting rod is provided at the bottom of the roller, the connecting rod is fixedly connected to the shaft of the roller, the connecting rod is located in the guide rail 2, the connecting rod is slidably connected to the guide rail 2, and the end of the connecting rod is fixedly connected to the slider.

[0010] Preferably, the sealing mechanism includes fixed plates symmetrically arranged on both sides of the connecting disk, the fixed plates are provided with grooves, a sliding plate is slidably arranged in the grooves, a threaded column is threadedly connected to the middle part of the sliding plate, the bottom of the threaded column is fixedly connected to the driving shaft, a disc is fixedly arranged on the top of the fixed plate, a connecting shaft is fixedly arranged on the top of the disc, and the outer surface of the connecting shaft is fixedly connected to the airbag.

[0011] Preferably, a second fixing plate is fixedly provided on the top of the connecting shaft, a top plate is fitted on the bottom of the airbag, sliding columns are symmetrically provided on the top plate, the sliding columns pass through the first fixing plate, and the bottom of the sliding columns is fixedly connected to the sliding plate.

[0012] Preferably, the blocking mechanism also includes a push rod fixedly arranged on the sliding rod, a piston cylinder is arranged above the push rod, one-way valves are arranged on both sides of the piston cylinder, a connecting pipe is connected to the one-way valve, a piston rod is slidably arranged in the piston cylinder, and the end of the piston rod is fixedly connected to the push rod.

[0013] Preferably, the connecting tube on one side passes through the disc and is communicated with the second airbag. An inflation tube is provided through the middle of the second airbag, and the inflation tube is communicated with an external inflator.

[0014] A method for using a duplex stainless steel welding device, using any of the duplex stainless steel welding devices described above, comprises the following steps: S1: Place the workpiece on the positioning mechanism, and then start the positioning mechanism to position and support the workpiece; S2: The positioning mechanism positions and supports both ends of the workpiece while the blocking mechanism blocks both ends of the workpiece; S3: Then, place the elbow pipe between the workpieces to be welded, and seal the opening on one side with paper tape; S4: Fill the workpiece with argon or other auxiliary welding gas through the sealing mechanism at one end, and then start the welding arm to perform the welding operation.

[0015] The beneficial effects of this application are: The present application provides a duplex stainless steel welding device and a method for using the same. When the driving shaft rotates, the connecting disk is driven to rotate synchronously, so that under the limiting effect of the figure-8 groove, the roller rolls along the groove wall, and during the rolling process, the connecting rod is prompted to move synchronously away from or towards each other. When the connecting rod moves synchronously away from each other, it pushes the slider to slide on the guide rail 1 and move synchronously away from each other, and supports one end of the workpiece inwardly through the support block 1. When the slider slides, the support block 2 on the fixed block is driven to move synchronously through the L-shaped rod, so that the support block 2 supports the other end of the workpiece inwardly. The support blocks 1 and 2 at both ends move synchronously, stably and without deviation, ensuring that the axis of the workpiece is centered and the workpiece can be quickly positioned.

[0016] The present application provides a duplex stainless steel welding device and method of use. The drive shaft drives the threaded column to rotate synchronously, prompting the sliding plate to move in the groove. When the sliding plate moves upward, the sliding column drives the top plate to squeeze the airbag 1, prompting the outer wall of the airbag 1 to gradually fit the inner wall of the workpiece, forming a sealing effect on one side of the workpiece. During welding, the auxiliary gas will not escape in large quantities, which can ensure the effectiveness of the protective gas, prevent oxidation, and improve the welding quality. Then, the push rod drives the piston rod to move synchronously when it moves away from each other, so that the gas in the piston cylinder enters the airbag 2 through the one-way valve. After being filled with gas, the airbag 2 gradually expands, and its outer surface gradually fits the inner wall of the other end of the workpiece, further sealing the workpiece. The push rod drives the airbag 2 to expand synchronously, and cooperates with the airbag 1 to achieve double sealing at both ends of the workpiece, ensuring that the leakage of welding auxiliary gas is greatly reduced, saving gas consumption and reducing production costs.

[0017] In addition to the above-described purposes, features and advantages, the present application has other purposes, features and advantages. The present application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention after removing the workpiece; Figure 3 It is a schematic diagram of the cross-section structure of the positioning mechanism and the blocking mechanism of the present invention; Figure 4 For the present invention Figure 3 Schematic diagram of the enlarged structure at A in the middle; Figure 5 Schematic diagram of the overall structure of the blocking mechanism of the present invention; Figure 6 It is a schematic diagram of the overall structure of the positioning mechanism and the blocking mechanism of the present invention; Figure 7 It is a schematic diagram of the cross-section structure of the positioning mechanism of the present invention; Figure 8 It is a schematic diagram of the local structure of the connection disk after cutting.

[0019] Description of the figure number: 1. Operating table; 2. Welding arm; 3. Welding gun; 4. Workpiece; 5. Positioning mechanism; 6. Guide rail 1; 7. Slider; 8. Support block 1; 9. Guide rail 2; 10. Drive shaft; 11. Connecting plate; 12. 8-shaped groove; 13. Roller; 14. Connecting rod; 15. Support block; 16. L-shaped rod; 17. Fixed block; 18. Support block 2; 19. Disc; 20. Slide groove; 21. Sliding rod; 22. Blocking mechanism; 23. Fixed plate; 24. Groove; 25. Sliding plate; 26. Threaded column; 27. Fixed plate 1; 28. Connecting shaft; 29. ​​Fixed plate 2; 30. Airbag 1; 31. Top plate; 32. Sliding column; 33. Push rod; 34. Piston cylinder; 35. One-way valve; 36. Piston rod; 37. Airbag 2; 38. Connecting pipe; 39. Inflating pipe. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] In order to enable those skilled in the art to better understand the present invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0022] Please refer to Figures 1 to 8A duplex stainless steel welding device includes: an operating table 1, a welding arm 2 is fixedly mounted on the operating table 1, a welding gun 3 is connected to the end of the welding arm 2, a workpiece 4 is placed on the operating table 1, the welding arm 2 adopts a 5-axis robotic arm driven by a servo motor, supports pitching, rotation, telescoping and other movements, realizes precise control of the spatial position of the welding gun 3, integrates an automatic wire feeding mechanism and an arc length tracking sensor, adjusts the height of the welding gun 3 in real time, and maintains arc stability.

[0023] Please refer to the Figures 1 to 4 as well as Figures 6 to 8 A duplex stainless steel welding device further includes: a positioning mechanism 5, which is disposed on an operating table 1 and includes a guide rail 1 6 symmetrically and fixedly disposed on the operating table 1. Each guide rail 1 6 is slidably connected to a slider 7, and each slider 7 is fixedly connected to a support block 1 8. The positioning mechanism 5 is used to quickly position a workpiece 4; an L-shaped rod 16 is fixedly disposed on one side of the slider 7, and a fixed block 17 is fixedly disposed on the end of the L-shaped rod 16 away from the slider 7. A support block 2 18 is fixedly disposed on the fixed block 17. A disk 19 is disposed between the support blocks 18, and a slidable groove 20 is symmetrically disposed on the disk 19. A sliding rod 21 is slidably disposed within the slidable groove 20, and the end of the sliding rod 21 is fixedly connected to the inner wall of the support block 18.

[0024] The positioning mechanism 5 also includes a guide rail 2 9 fixedly mounted on the operating table 1 and a support block 15. The top of the support block 15 is configured as an arc surface. The guide rail 2 9 is positioned between the guide rails 1 6. A drive shaft 10 is rotatably connected to the middle of the guide rail 2 9. The drive shaft 10 is externally connected to an external drive. A connecting disk 11 is fixedly connected to the drive shaft 10. The connecting disk 11 has an 8-shaped groove 12. The inner wall of the 8-shaped groove 12 is symmetrically and slidably connected to a roller 13. A connecting rod 14 is provided at the bottom of the roller 13. The connecting rod 14 is fixedly connected to the shaft of the roller 13. The connecting rod 14 is located within the guide rail 2 9 and is slidably connected to the guide rail 2 9. The end of the connecting rod 14 is fixedly connected to the slider 7.

[0025] In this embodiment, the connecting disk 11 is driven to rotate synchronously by the driving shaft 10, so that under the limiting effect of the 8-shaped groove 12, the roller 13 rolls along its groove wall, and during the rolling process, the connecting rod 14 is prompted to move away from or towards each other synchronously. When the connecting rod 14 moves away from each other synchronously, it will push the slider 7 to slide on the guide rail 16 and move away from each other synchronously, and support block 18 will be used to support and position one end of the workpiece 4. When the slider 7 slides, the L-shaped rod 16 drives the support block 2 18 on the fixed block 17 to move synchronously, prompting the support block 2 18 to support and position the other end of the workpiece 4 internally. The support blocks 1 8 and 18 at both ends move synchronously, stably and without deviation, ensuring that the axis of the workpiece 4 is centered and the workpiece 4 can be quickly positioned.

[0026] Please refer to the Figures 1 to 5as well as Figures 7 and 8 A duplex stainless steel welding device further includes a blocking mechanism 22, which is disposed on the positioning mechanism 5. The blocking mechanism 22 includes an airbag 1 30 and an airbag 2 37 disposed on the inner walls of both ends of the workpiece 4. The blocking mechanism 22 is used to block both ends of the workpiece 4. The blocking mechanism 22 includes a fixed plate 23 symmetrically disposed on both sides of the connecting disk 11. The fixed plate 23 has a groove 24, and a sliding plate 25 is slidably disposed in the groove 24. A threaded column 26 is threadedly connected to the middle of the sliding plate 25. The bottom of the threaded column 26 is fixedly connected to the drive shaft 10. A circular disk 19 is fixedly disposed on the top of the fixed plate 23. A connecting shaft 28 is fixedly disposed on the top of the circular disk 19. The outer surface of the connecting shaft 28 is fixedly connected to the airbag 1 30. A fixed disk 29 is fixedly disposed on the top of the connecting shaft 28. A top plate 31 is attached to the bottom of the airbag 1 30. Sliding columns 32 are symmetrically disposed on the top plate 31. The sliding columns 32 pass through the fixed disk 1 27. The bottom of the sliding columns 32 is fixedly connected to the sliding plate 25.

[0027] In this embodiment, the threaded column 26 is driven to rotate synchronously by the drive shaft 10, prompting the sliding plate 25 to move in the groove 24. When the sliding plate 25 moves upward, the sliding column 32 drives the top plate 31 to squeeze the airbag 30, prompting the outer wall of the airbag 30 to gradually fit on the inner wall of the workpiece 4, forming a sealing effect on one side of the workpiece 4. During welding, the auxiliary gas will not escape in large quantities, which can ensure the effectiveness of the protective gas, prevent oxidation, and improve the welding quality.

[0028] Specifically, the blocking mechanism 22 also includes a push rod 33 fixedly mounted on the sliding rod 21. A piston cylinder 34 is disposed above the push rod 33. One-way valves 35 are disposed on either side of the piston cylinder 34. A connecting pipe 38 is connected to the one-way valve 35. A piston rod 36 is slidably disposed within the piston cylinder 34, and the end of the piston rod 36 is fixedly connected to the push rod 33. One end of the connecting pipe 38 passes through the disc 19 and communicates with the second airbag 37. An inflation pipe 39 is disposed in the middle of the second airbag 37 and is connected to an external inflator.

[0029] In this embodiment, the synchronous, diverging movement of push rod 33 drives the synchronous movement of piston rod 36, allowing gas within piston cylinder 34 to enter second airbag 37 through one-way valve 35. After being filled with gas, second airbag 37 gradually expands, its outer surface gradually coming into contact with the inner wall of the other end of workpiece 4, further sealing workpiece 4. Push rod 33 drives the synchronous expansion of second airbag 37, which cooperates with first airbag 30 to achieve a double seal at both ends of workpiece 4, significantly reducing leakage of welding auxiliary gas, saving gas usage, and lowering production costs.

[0030] A method for using a duplex stainless steel welding device, which is used in any of the above duplex stainless steel welding devices, comprises the following steps: S1: placing the workpiece 4 on the positioning mechanism 5, and then starting the positioning mechanism 5 to position and support the workpiece 4; S2: The positioning mechanism 5 positions and supports both ends of the workpiece 4 while the blocking mechanism 22 blocks both ends of the workpiece 4; S3: The elbow pipe is then placed between the workpieces 4 to be welded, and the opening on one side is sealed using paper tape; S4: filling the workpiece 4 with argon or other auxiliary welding gas through the sealing mechanism 22 at one end, and then starting the welding arm 2 to perform the welding operation.

[0031] The above method uses the positioning mechanism 5 to initially position and support the workpiece 4 to be welded. At the same time, during the operation of the positioning mechanism 5, the airbag 1 30 and the airbag 2 37 of the blocking mechanism 22 gradually fit the openings at both ends of the workpiece 4 under the linkage of the positioning mechanism 5 to block them. Then, auxiliary welding gas is filled into the workpiece 4 to perform the welding operation. The positioning mechanism 5 first precisely supports the workpiece 4. During positioning, the airbag 1 30 and the airbag 2 37 gradually expand as the positioning mechanism 5 moves, flexibly filling the gaps at both ends of the workpiece 4, achieving double blocking at both ends of the workpiece 4 and ensuring that the leakage of welding auxiliary gas is greatly reduced. Positioning and blocking are performed first, and then the auxiliary gas is filled to form a closed cavity, ensuring that the airflow evenly covers the welding area, reducing protection failure caused by gas escape, and improving the stability of weld quality.

[0032] Through all the above embodiments, this solution is specifically as follows: First, place the workpiece 4 (i.e., duplex stainless steel pipe) to be welded on the outer surface of support block 18, support block 2 18, and support block 15 respectively, and then start the external drive of the drive shaft 10 to prompt the drive shaft 10 to start rotating. When the drive shaft 10 rotates, it will drive the connecting disk 11 to rotate synchronously. Under the restriction of the 8-shaped groove 12, the roller 13 will roll along its groove wall, and in the process of rolling, it will prompt the connecting rod 14 to move away from each other or move towards each other synchronously. When the connecting rod 14 moves away from each other synchronously, it will push the slider 7 to slide on the guide rail 16 and move away from each other synchronously, and support block 18 will be used to support one end of the workpiece 4 inwardly. When the slider 7 slides, the support block 2 18 on the fixed block 17 is driven to move synchronously through the L-shaped rod 16, prompting the support block 2 18 to support the other end of the workpiece 4 inwardly. The support block 1 8 and the support block 2 18 at the end move synchronously, stably and without deviation, ensuring that the axis of the workpiece 4 is centered and the workpiece 4 can be quickly positioned; secondly, while the positioning mechanism 5 positions the inner support, the drive shaft 10 will drive the threaded column 26 to rotate synchronously, prompting the sliding plate 25 to move in the groove 24. When the sliding plate 25 moves upward, the sliding column 32 drives the top plate 31 to squeeze the airbag 1 30, prompting the outer wall of the airbag 1 30 to gradually fit against the inner wall of the workpiece 4, forming a sealing effect on one side of the workpiece 4. At the same time, the push rod 33 drives the piston rod 36 to move synchronously when it moves away from the piston rod 33, so that the gas in the piston cylinder 34 enters the airbag 2 37 through the one-way valve 35. The airbag 2 37 gradually expands after being filled with gas, and its outer surface gradually fits against the inner wall of the other end of the workpiece 4, further sealing the workpiece 4. The push rod 33 links the airbag 2 37 to expand synchronously, and cooperates with the airbag 1 30 to achieve double sealing at both ends of the workpiece 4, ensuring that the leakage of welding auxiliary gas is greatly reduced, saving gas consumption, and reducing production costs. During welding, the auxiliary gas will not escape in large quantities, which can ensure the effectiveness of the protective gas, prevent oxidation, and improve the welding quality; finally, the elbow pipe is placed between the workpieces 4 to be welded, and the opening on one side is sealed with paper tape, and argon or other auxiliary welding gases are filled into the workpiece 4 through the sealing mechanism 22 at one end, and then the welding arm 2 is started to perform the welding operation. When the welding is completed, the drive shaft 10 is started again to rotate it in the opposite direction, and the positioning mechanism 5 releases the limit of the workpiece 4 that has been welded, and the worker can remove the workpiece 4 and perform the welding operation on the next workpiece 4.

[0033] It should be understood by those skilled in the art that the discussion of any of the above embodiments is merely illustrative, and within the scope of the present invention, the technical features of the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0034] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A duplex stainless steel welding device comprising: An operating table (1), wherein a welding arm (2) is fixedly provided on the operating table (1), a welding gun (3) is connected to the end of the welding arm (2), and a workpiece (4) is placed on the operating table (1), characterized in that it further comprises: A positioning mechanism (5), wherein the positioning mechanism (5) is arranged on the operating table (1), and the positioning mechanism (5) comprises a guide rail (6) symmetrically and fixedly arranged on the operating table (1), wherein the guide rail (6) is slidably connected to a slider (7), and the slider (7) is fixedly connected to a support block (8), and the positioning mechanism (5) is used to quickly position the workpiece (4); A blocking mechanism (22) is provided on the positioning mechanism (5), and the blocking mechanism (22) comprises an airbag 1 (30) and an airbag 2 (37) provided on the inner walls of both ends of the workpiece (4). The blocking mechanism (22) is used to block both ends of the workpiece (4).

2. A duplex stainless steel welding device according to claim 1, characterized in that: An L-shaped rod (16) is fixedly provided on one side of the slider (7), a fixed block (17) is fixedly provided on one end of the L-shaped rod (16) away from the slider (7), and a second support block (18) is fixedly provided on the fixed block (17).

3. A duplex stainless steel welding device according to claim 2, characterized in that: A disc (19) is provided between the two support blocks (18), a slide groove (20) is symmetrically provided on the disc (19), a sliding rod (21) is slidably provided in the slide groove (20), and the end of the sliding rod (21) is fixedly connected to the inner wall of the two support blocks (18).

4. The duplex stainless steel welding device according to claim 1, characterized in that: The positioning mechanism (5) further comprises a guide rail 2 (9) and a support block (15) fixedly arranged on the operating table (1), wherein the top of the support block (15) is arranged as an arc surface, the guide rail 2 (9) is arranged between the guide rail 1 (6), and a drive shaft (10) is rotatably connected to the middle of the guide rail 2 (9), and the drive shaft (10) is externally connected to an external drive.

5. A duplex stainless steel welding device according to claim 4, characterized in that: The driving shaft (10) is fixedly connected to a connecting disk (11), an 8-shaped groove (12) is provided on the connecting disk (11), and a roller (13) is symmetrically slidably connected to the inner wall of the 8-shaped groove (12), and a connecting rod (14) is provided at the bottom of the roller (13), and the connecting rod (14) is fixedly connected to the shaft of the roller (13), and the connecting rod (14) is located in the guide rail 2 (9), and the connecting rod (14) is slidably connected to the guide rail 2 (9), and the end of the connecting rod (14) is fixedly connected to the slider (7).

6. The duplex stainless steel welding device according to claim 1, characterized in that: The blocking mechanism (22) includes a fixed plate (23) symmetrically arranged on both sides of the connecting disk (11), the fixed plate (23) is provided with a groove (24), a sliding plate (25) is slidably arranged in the groove (24), a threaded column (26) is threadedly connected to the middle of the sliding plate (25), the bottom of the threaded column (26) is fixedly connected to the driving shaft (10), a disc (19) is fixedly arranged on the top of the fixed plate (23), a connecting shaft (28) is fixedly arranged on the top of the disc (19), and the outer surface of the connecting shaft (28) is fixedly connected to the airbag (30).

7. A duplex stainless steel welding device according to claim 6, characterized in that: A second fixing plate (29) is fixedly provided on the top of the connecting shaft (28), a top plate (31) is fitted on the bottom of the airbag (30), and sliding columns (32) are symmetrically provided on the top plate (31). The sliding columns (32) pass through the first fixing plate (27), and the bottom of the sliding columns (32) is fixedly connected to the sliding plate (25).

8. The duplex stainless steel welding device according to claim 7, characterized in that: The blocking mechanism (22) further comprises a push rod (33) fixedly arranged on the sliding rod (21), a piston cylinder (34) being arranged above the push rod (33), one-way valves (35) being arranged on both sides of the piston cylinder (34), a connecting pipe (38) being connected to the one-way valve (35), a piston rod (36) being slidably arranged in the piston cylinder (34), and an end of the piston rod (36) being fixedly connected to the push rod (33).

9. The duplex stainless steel welding device according to claim 8, characterized in that: The connecting pipe (38) on one side passes through the disc (19) and is in communication with the second airbag (37). An inflation pipe (39) is provided through the middle of the second airbag (37), and the inflation pipe (39) is in communication with an external inflator.

10. A method for using a duplex stainless steel welding device, wherein the method is used in the duplex stainless steel welding device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: placing the workpiece (4) on the positioning mechanism (5), and then starting the positioning mechanism (5) to position and support the workpiece (4); S2: The positioning mechanism (5) positions and supports both ends of the workpiece (4) while the blocking mechanism (22) blocks both ends of the workpiece (4); S3: The elbow pipe is then placed between the workpieces to be welded (4), and the opening on one side is sealed using paper tape; S4: Filling the workpiece (4) with argon gas or other auxiliary welding gas through the sealing mechanism (22) at one end, and then starting the welding arm (2) to perform the welding operation.

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