Butt joint device for 9Ni steel butt welding

Abstract

The invention relates to the technical field of welding equipment, and discloses a 9Ni steel butt welding butt joint device which comprises a base plate, a mounting groove is formed in the center of the upper end surface of the base plate, positioning grooves are formed in the upper end surface of the base plate and located on the two sides of the mounting groove, and supporting pipes are arranged at the two ends of the upper end surface of the base plate through the positioning grooves. Supporting columns are slidably arranged in the two supporting pipes, n-shaped supporting rods are arranged at the upper ends of the two supporting columns correspondingly, rotating bases are rotatably arranged at the two ends of the two n-shaped supporting rods correspondingly, and U-shaped containing tables are arranged at the two ends of the surfaces of the upper ends of the rotating bases correspondingly. According to the butt joint device for 9Ni steel butt welding, the U-shaped containing tables are installed on the rotating bases at the two ends of the n-shaped supporting rod, two workers can conduct welding operation at the same time, after the front faces of the two 9Ni steel plates are welded, the U-shaped containing tables and the 9Ni steel plates fixed to the U-shaped containing tables can be turned over, operation is easy, and time and labor are saved.

Description

Technical Field

[0001] The invention relates to the technical field of welding equipment, in particular to a butt welding device for 9Ni steel butt welding. Background Art

[0002] 9Ni steel is an ultra-low temperature steel with a nickel content of about 9%. It has excellent low-temperature toughness, high strength, corrosion resistance and good welding performance. It is widely used in the manufacture of large LNG storage tanks, cryogenic pressure vessels and other equipment.

[0003] At present, the welding methods that can be used for 9Ni steel are mainly: arc welding and submerged arc welding. In the process of butt welding two 9Ni steel plates, a butt welding device is often required for auxiliary welding. Generally, the two 9Ni steel plates are placed on the workbench of the butt welding device and fixed by a clamp. During welding, a 30° groove is opened on one side of the parent material, and no gap is left when the front side is welded. After the front side welding is completed, the back side is cleaned with a carbon arc air planer and polished before welding.

[0004] The workbench of the existing butt-jointing device is suitable for using a V-shaped groove without leaving a gap. During welding, the welding rod cannot reach the root of the groove, resulting in an increase in the depth of the carbon arc gouging on the back, which increases the number of weld passes and causes the welding deformation to be uncontrollable; the existing butt-jointing device generally only allows one worker to perform welding operations, and the butt-jointing device cannot be height-adjusted as needed; after welding the front side of the 9Ni steel plate, the clamp needs to be loosened, and the worker flips the 9Ni steel, fixes it again and welds it. The operation steps are cumbersome, time-consuming and labor-intensive, and the labor intensity of the workers is increased. Therefore, it is necessary to provide a butt-jointing device for butt welding of 9Ni steel to solve the above problems. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a butt welding device for 9Ni steel butt welding, which solves the problems mentioned in the above background.

[0006] The present invention provides the following technical solution: a butt welding device for 9Ni steel butt welding, comprising a base plate; an installation groove is provided at the center of the upper surface of the base plate, positioning grooves are provided on the upper surface of the base plate and on both sides of the installation groove, support tubes are provided at both ends of the upper surface of the base plate through the positioning grooves, a height adjustment component is provided at the center of the upper surface of the base plate and between the two support tubes, support columns are slidably provided inside the two support tubes, the upper ends of the support columns extend to the outside through the upper openings of the support tubes, the upper ends of the two support columns are provided with "J"-shaped support rods, and rotating seats are rotatably provided at both ends of the two "J"-shaped support rods, and U-shaped placing tables are provided at both ends of the upper surface of the rotating seat, and a fixing component is provided on the U-shaped placing table.

[0007] Preferably, the height adjustment assembly includes a drive motor, an adjustment screw and a lifting rod, the lower end of the drive motor is inserted into the mounting groove, and the output end of the drive motor is fixedly connected to the lower end of the adjustment screw.

[0008] Preferably, a nut is provided at the middle end of the lifting rod, and the lifting rod is threadedly connected to the adjusting screw through the nut. The two support tubes are provided with strip grooves at the middle ends of the side walls close to each other, and the two ends of the lifting rod are respectively passed through the strip grooves of the two support tubes and fixedly connected to the lower end of the support column.

[0009] Preferably, a top connecting plate is provided at the upper ends of one side of the two support tubes close to each other, and a protective baffle is clamped on the upper surface of the top connecting plate via a clamping seat.

[0010] Preferably, both ends of the I-shaped support rod are provided with connecting shafts, the I-shaped support rod is rotatably connected to the rotating seat via the connecting shaft, and both ends of the lower end surface of the rotating seat are provided with limited support columns.

[0011] Preferably, the fixing component is arranged on two U-shaped placement platforms on the upper end surface of the rotating seat, with two ends away from each other on one side. The fixing component includes a column, a strip mounting plate and a clamping screw. The lower end of the column is connected to the U-shaped placement platform, and the strip mounting plate is arranged at the top of the column.

[0012] Preferably, one end of the strip mounting plate away from the column is threadedly connected to the clamping screw, a pressure plate is provided at the lower end of the clamping screw, and an upper end of the clamping screw passes through the strip mounting plate and is provided with a knob.

[0013] Preferably, positioning vertical plates are fixedly provided on the outer surfaces of the side walls at both ends of the "X"-shaped support rod, threaded holes are provided at both ends of the positioning vertical plates, positioning pins are provided on the positioning vertical plates through the threaded holes, the front end surface of the positioning pin shaft is smooth, and positioning holes that cooperate with the positioning pins are provided in the center of the side walls at both ends of the U-shaped placing table.

[0014] Preferably, universal wheels are provided at the four corners of the lower surface of the base plate, mounting holes are provided at the middle ends of both sides of the lower surface of the base plate, and support assemblies are provided at the centers of both ends of the base plate, and the support assemblies include Z-shaped side panels, support screws and support feet, the upper plate of the Z-shaped side panel is fixedly connected to the base plate, the support screw is threadedly connected to the bottom plate of the Z-shaped side panel, the support foot is provided at the lower end of the support screw, and the upper end of the support screw passes through the Z-shaped side panel and is provided with a handle.

[0015] Preferably, the two U-shaped placement tables arranged at both ends of the upper end surface of the rotating seat are respectively used to place two 9Ni steel plates to be welded. The two 9Ni steel plates adopt X-shaped grooves, with 30° on the front and back sides respectively, and a group gap of 2-4mm. The first welding method adopts argon arc welding single-sided welding and double-sided forming, and then arc welding is used to perform front and back alternating welding until the welding is completed.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The butt welding device of 9Ni steel butt welding is provided with a height adjustment component. The driving motor can effectively drive the adjusting screw to rotate synchronously. Under the limiting effect of the support tube, the lifting rod moves up and down along the vertical direction of the adjusting screw. During the up and down movement of the lifting rod, the supporting column can be driven to move up and down synchronously, thereby realizing effective adjustment of the height of the U-shaped placement table, which is convenient for welding personnel to perform welding operations. By setting the top connecting plate, it is convenient to install the protective baffle. By setting the protective baffle, mutual interference can be avoided when two workers perform welding operations at the same time.

[0018] 2. The butt welding device of 9Ni steel butt welding is provided with connecting shafts at both ends of the I-shaped support rod, so that rotating seats are installed at both ends of the I-shaped support rod, and the rotating seats are rotatable. U-shaped placement tables are installed on the rotating seats at both ends of the I-shaped support rod, so that two workers can perform welding operations at the same time. After the front welding of two 9Ni steel plates is completed, the positioning pin on the upper end of the positioning vertical plate is rotated to remove the U-shaped placement table and the 9Ni steel plate fixed thereon can be flipped over, and then the positioning pin is rotated to pass through the threaded hole at the lower end of the positioning vertical plate and inserted into the positioning hole on the U-shaped placement table, so as to ensure the stability of the U-shaped placement table after flipping. The operation is simple, time-saving and labor-saving.

[0019] 3. The butt welding device of 9Ni steel butt welding is provided with a fixed component. When the 9Ni steel plate is placed on the upper end surface of the U-shaped placing table, the pressing screw can be driven to rotate and move downward by turning the knob. During the downward movement of the pressing screw, the pressure plate can be driven to move downward synchronously and press the 9Ni steel plate to ensure the stability of the 9Ni steel plate. The two U-shaped placing tables can be used to place two 9Ni steel plates to be welded respectively. It can not only adapt to the butt welding method using an X-shaped groove, but also can adopt a single-sided 30° groove, a pairing gap of 2-4mm, and a 20mm anti-deformation reserved after pairing for butt welding. Similarly, the first welding method adopts the argon arc welding single-sided welding and double-sided forming welding method, and then the welding rod arc welding is used for welding until the welding is completed. Both methods no longer require carbon arc air planing to clean the root, which can effectively control welding deformation, while reducing the labor intensity of operators and improving the working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is one of the overall structural schematic diagrams of the butt welding device for 9Ni steel butt welding of the present invention;

[0021] Figure 2 The second schematic diagram of the overall structure of the butt welding device for 9Ni steel butt welding of the present invention;

[0022] Figure 3 It is a schematic diagram of the installation structure of the support pipe and the support column of the present invention;

[0023] Figure 4 It is a structural schematic diagram of the base plate and the supporting assembly of the present invention;

[0024] Figure 5 It is a schematic diagram of the working principle of the height adjustment assembly of the present invention;

[0025] Figure 6 It is a structural schematic diagram of the X-shaped support rod and the positioning vertical plate of the present invention;

[0026] Figure 7 It is a structural schematic diagram of a U-shaped placement table and a fixing assembly of the present invention;

[0027] Figure 8 It is a structural schematic diagram of two 9Ni steel plates to be welded in the butt joint state of the present invention;

[0028] Fig. 9 For the present invention Figure 2 A magnified schematic diagram of the structure in the middle.

[0029] In the figure: 1. base plate; 101. mounting groove; 102. positioning groove; 2. universal wheel; 3. support assembly; 301. Z-shaped side plate; 302. support screw; 303. support foot; 4. support tube; 401. strip groove; 5. support column; 6. height adjustment assembly; 601. drive motor; 602. adjustment screw; 603. lifting rod; 7. "X"-shaped support rod; 701. connecting shaft; 8. rotating seat; 9. U-shaped placement table; 901. positioning hole; 10. top connecting plate; 11. protective baffle; 12. fixing assembly; 1201. column; 1202. strip mounting plate; 1203. clamping screw; 1204. pressure plate; 13. 9Ni steel plate; 1301. X-shaped groove; 14. positioning vertical plate; 1401. positioning pin. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] See also Figure 1-9 , a butt welding device for 9Ni steel butt welding comprises a base plate 1; a mounting groove 101 is provided at the center of the upper end surface of the base plate 1, and positioning grooves 102 are provided on the upper end surface of the base plate 1 and on both sides of the mounting groove 101, and support tubes 4 are provided at both ends of the upper end surface of the base plate 1 through the positioning grooves 102, and a height adjustment component 6 is provided at the center of the upper end surface of the base plate 1 and between the two support tubes 4, and support columns 5 are slidably provided inside the two support tubes 4, and the upper ends of the support columns 5 extend to the outside through the upper end openings of the support tubes 4, and the upper ends of the two support columns 5 are provided with "J"-shaped support rods 7, and the two "J"-shaped support rods 7 are rotatably provided with rotating seats 8 at both ends, and U-shaped placing tables 9 are provided at both ends of the upper end surface of the rotating seat 8, and a fixing component 12 is provided on the U-shaped placing table 9.

[0032] Among them; the height adjustment component 6 includes a driving motor 601, an adjusting screw 602 and a lifting rod 603, the lower end of the driving motor 601 is inserted into the installation groove 101, the output end of the driving motor 601 is fixedly connected to the lower end of the adjusting screw 602, a nut is provided at the middle end of the lifting rod 603, and the lifting rod 603 is threadedly connected to the adjusting screw 602 through the nut, and the middle ends of the side walls of the two support tubes 4 close to each other are provided with strip notches 401, and the two ends of the lifting rod 603 pass through the strip notches 401 of the two support tubes 4 and are fixedly connected to the lower ends of the support columns 5, the driving motor 601 is electrically connected to the external power supply through a wire, and the driving motor 601 can effectively drive the adjusting screw 602 to rotate synchronously through the operation of the driving motor 601, and under the limiting action of the support tube 4, the lifting rod 603 moves up and down in the vertical direction of the adjusting screw 602, and the lifting rod 603 can drive the support column 5 to move up and down synchronously during the up and down movement, thereby realizing the effective adjustment of the height of the U-shaped placement table 9, which is convenient for welders to perform welding operations.

[0033] Among them; a top connecting plate 10 is arranged on the upper end of one side where two support tubes 4 are close to each other, and a protective baffle 11 is clamped on the upper surface of the top connecting plate 10 through a clamping seat. By setting the top connecting plate 10, it is convenient to install the protective baffle 11. By setting the protective baffle 11, it is avoided that two workers interfere with each other when performing welding operations at the same time.

[0034] Among them; the fixing component 12 is arranged on the two U-shaped placing platforms 9 on the upper end surface of the rotating seat 8, and the two ends of one side are far away from each other. The fixing component 12 includes a column 1201, a strip mounting plate 1202 and a clamping screw 1203. The lower end of the column 1201 is connected to the U-shaped placing platform 9, the strip mounting plate 1202 is arranged at the top of the column 1201, and the strip mounting plate 1202 is threadedly connected to the clamping screw 1203 at one end away from the column 1201, and a pressure plate 1204 is arranged at the lower end of the clamping screw 1203. The upper end of the clamping screw 1203 passes through the strip mounting plate 1202 and is provided with a knob. When the 9Ni steel plate 13 is placed on the upper end surface of the U-shaped placing platform 9, the clamping screw 1203 can be driven to rotate and move downward by rotating the knob. During the downward movement of the clamping screw 1203, the pressure plate 1204 can be driven to move downward synchronously and clamp the 9Ni steel plate 13 to ensure the stability of the 9Ni steel plate 13.

[0035] Among them; both ends of the "Ji"-shaped support rod 7 are provided with connecting shafts 701, and the "Ji"-shaped support rod 7 is rotatably connected to the rotating seat 8 through the connecting shaft 701. Both ends of the lower end surface of the rotating seat 8 are provided with limited support columns. Positioning vertical plates 14 are fixedly provided on the outer surfaces of the side walls of both ends of the "Ji"-shaped support rod 7. Threaded holes are provided at both ends of the positioning vertical plates 14. Positioning pins 1401 are provided through the threaded holes of the positioning vertical plates 14. The front end surface of the positioning pin 1401 is smooth, and the center of the side walls at both ends of the U-shaped placement table 9 is provided with positioning holes 901 that cooperate with the positioning pin 1401. By providing connecting shafts 701 at both ends of the "Ji"-shaped support rod 7, A rotating seat 8 is installed at both ends of the "X"-shaped support rod 7, and the rotating seat 8 is rotatable. A U-shaped placement table 9 is installed on the rotating seat 8 at both ends of the "X"-shaped support rod 7, which can enable two workers to perform welding operations at the same time. After the front welding of the two 9Ni steel plates 13 is completed, the positioning pin 1401 at the upper end of the positioning vertical plate 14 is rotated to remove the U-shaped placement table 9 and the 9Ni steel plate 13 fixed thereon can be flipped over, and then the positioning pin 1401 is rotated to pass through the threaded hole at the lower end of the positioning vertical plate 14 and inserted into the positioning hole 901 on the U-shaped placement table 9, thereby ensuring the stability of the U-shaped placement table 9 after the flip. The operation is simple, saving time and effort.

[0036] Among them; universal wheels 2 are arranged at the four corners of the lower end surface of the base plate 1, mounting holes are arranged at the middle ends of the two sides of the lower end surface of the base plate 1, and support components 3 are arranged at the centers of both ends of the base plate 1. The support components 3 include Z-shaped side plates 301, support screws 302 and support feet 303. The upper plate of the Z-shaped side plate 301 is fixedly connected to the base plate 1, and the support screws 302 are threadedly connected to the bottom plate of the Z-shaped side plate 301. The support feet 303 are arranged at the lower end of the support screws 302, and the upper end of the support screws 302 passes through the Z-shaped side plates 301 and is provided with a handle. By providing a universal wheel 2, it is convenient to move the 9Ni steel butt welding docking device for effective position adjustment, saving time and effort. After the position adjustment of the 9Ni steel butt welding docking device is completed, the handle is turned to drive the support screw 302 to rotate and move downward. During the downward movement of the support screw 302, the support foot 303 is driven to move downward synchronously and contact the ground, which can effectively ensure the stability of the 9Ni steel butt welding docking device. Another mounting hole is opened on the lower end surface of the base plate 1 to connect a side support rod to further ensure the stability of the 9Ni steel butt welding docking device.

[0037] Among them; the two U-shaped placement tables 9 set at both ends of the upper end surface of the rotating seat 8 are used to place two 9Ni steel plates 13 to be welded. The two 9Ni steel plates 13 adopt an X-shaped groove 1301, 30° on the front and back sides, and a gap of 2-4mm between the groups. The first pass adopts a argon arc welding single-sided welding and double-sided forming welding method, and then the front and back sides are staggered welded by arc welding until the welding is completed. By setting two U-shaped placement tables 9 at both ends of the upper end surface of the rotating seat 8, the two U-shaped placement tables 9 can be used to place two The 9Ni steel plates 13 to be welded can not only adapt to the butt jointing method using the X-shaped groove 1301, but also adopt a single-sided 30° groove, a pairing gap of 2-4mm, and reserve 20mm of anti-deformation for butt jointing after pairing. Similarly, the first pass adopts the argon arc welding single-sided welding and double-sided forming welding method, and then uses the electrode arc welding to weld until the welding is completed. Both methods no longer require carbon arc air planing to clean the root, which can effectively control the welding deformation, while reducing the labor intensity of the operators and improving the working environment.

[0038] Working principle: by setting two U-shaped placing tables 9 at both ends of the upper end surface of the rotating seat 8, the two U-shaped placing tables 9 can be used to place two 9Ni steel plates 13 to be welded respectively. When the 9Ni steel plate 13 is placed on the upper end surface of the U-shaped placing table 9, the pressing screw 1203 can be driven to rotate and move downward by turning the knob. During the downward movement of the pressing screw 1203, the pressure plate 1204 can be driven to move downward synchronously and press the 9Ni steel plate 13 to ensure the stability of the 9Ni steel plate 13. The two U-shaped placing tables 9 can be used to place two The 9Ni steel plate 13 to be welded can not only adapt to the butt jointing method using the X-shaped groove 1301, but also adopt a single-sided 30° groove, a pairing gap of 2-4mm, and reserve 20mm of anti-deformation for butt jointing after pairing. Similarly, the first pass adopts the argon arc welding single-sided welding and double-sided forming welding method, and then uses the electrode arc welding to weld until the welding is completed. Both methods no longer require carbon arc air planing to clean the root, which can effectively control the welding deformation, while reducing the labor intensity of the operators and improving the working environment.

[0039] Furthermore, by providing connecting shafts 701 at both ends of the I-shaped support rod 7, it is convenient to install the rotating seat 8 at both ends of the I-shaped support rod 7, and the rotating seat 8 can be rotatable. A U-shaped placement table 9 is installed on the rotating seat 8 at both ends of the I-shaped support rod 7, which can enable two workers to perform welding operations at the same time. After the front welding of the two 9Ni steel plates 13 is completed, the positioning pin 1401 at the upper end of the positioning vertical plate 14 is rotated to remove the U-shaped placement table 9 and the 9Ni steel plate 13 fixed thereon can be flipped over, and then the positioning pin 1401 is rotated to pass through the threaded hole at the lower end of the positioning vertical plate 14 and inserted into the positioning hole 901 on the U-shaped placement table 9, thereby ensuring the stability of the U-shaped placement table 9 after the flip. The operation is simple, saving time and effort.

[0040] Furthermore, by providing a height adjustment component 6, the driving motor 601 can effectively drive the adjusting screw 602 to rotate synchronously. Under the limiting action of the support tube 4, the lifting rod 603 moves up and down in the vertical direction along the adjusting screw 602. During the up and down movement of the lifting rod 603, the supporting column 5 can be driven to move up and down synchronously, thereby realizing effective adjustment of the height of the U-shaped placement table 9, which is convenient for welding personnel to perform welding operations. By providing a top connecting plate 10, it is convenient to install a protective baffle 11. By providing the protective baffle 11, mutual interference between two workers when performing welding operations at the same time can be avoided.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. 9Ni steel butt welding device, characterized in that, The invention comprises a base plate (1); a mounting groove (101) is provided at the center of the upper surface of the base plate (1); positioning grooves (102) are provided on the upper surface of the base plate (1) and on both sides of the mounting groove (101); support tubes (4) are provided at both ends of the upper surface of the base plate (1) through the positioning grooves (102); a height adjustment component (6) is provided at the center of the upper surface of the base plate (1) and between the two support tubes (4); support columns (5) are slidably provided inside the two support tubes (4); the upper ends of the support columns (5) extend to the outside through the upper openings of the support tubes (4); the upper ends of the two support columns (5) are provided with "J"-shaped supporting rods (7); the two ends of the two "J"-shaped supporting rods (7) are rotatably provided with rotating seats (8); the upper ends of the rotating seats (8) are provided with U-shaped placing platforms (9) at both ends of the upper surface of the rotating seats (8); and a fixing component (12) is provided on the U-shaped placing platform (9).

2. The butt welding device for 9Ni steel butt welding according to claim 1, characterized in that: The height adjustment assembly (6) comprises a driving motor (601), an adjusting screw (602) and a lifting rod (603); the lower end of the driving motor (601) is inserted into the installation groove (101); and the output end of the driving motor (601) is fixedly connected to the lower end of the adjusting screw (602).

3. The butt welding device for 9Ni steel butt welding according to claim 2 is characterized in that: A nut is provided at the middle end of the lifting rod (603), and the lifting rod (603) is threadedly connected to the adjusting screw (602) via the nut. A strip-shaped notch (401) is provided at the middle end of the side walls of the two support tubes (4) close to each other, and the two ends of the lifting rod (603) respectively pass through the strip-shaped notches (401) of the two support tubes (4) and are fixedly connected to the lower ends of the support columns (5).

4. The butt welding device for 9Ni steel butt welding according to claim 3 is characterized in that: A top connecting plate (10) is provided at the upper ends of one side of the two support tubes (4) close to each other, and a protective baffle (11) is clamped on the upper end surface of the top connecting plate (10) via a clamping seat.

5. The butt welding device for 9Ni steel butt welding according to claim 1, characterized in that: Both ends of the "X"-shaped support rod (7) are provided with connecting shafts (701), and the "X"-shaped support rod (7) is rotatably connected to the rotating seat (8) via the connecting shafts (701), and both ends of the lower end surface of the rotating seat (8) are provided with limited support columns.

6. The butt welding device for 9Ni steel butt welding according to claim 1, characterized in that: The fixing component (12) is arranged on two U-shaped placement platforms (9) on the upper end surface of the rotating seat (8) and are far away from each other at two ends of one side. The fixing component (12) includes a column (1201), a strip mounting plate (1202) and a clamping screw (1203). The lower end of the column (1201) is connected to the U-shaped placement platform (9), and the strip mounting plate (1202) is arranged on the top of the column (1201).

7. The butt welding device for 9Ni steel butt welding according to claim 6, characterized in that: The end of the strip mounting plate (1202) away from the column (1201) is threadedly connected to the clamping screw (1203), the lower end of the clamping screw (1203) is provided with a pressure plate (1204), and the upper end of the clamping screw (1203) passes through the strip mounting plate (1202) and is provided with a knob.

8. The butt welding device for 9Ni steel butt welding according to claim 1, characterized in that: Positioning vertical plates (14) are fixedly arranged on the outer surfaces of the side walls at both ends of the "X"-shaped support rod (7), and threaded holes are opened at both ends of the positioning vertical plates (14). Positioning pins (1401) are arranged on the positioning vertical plates (14) through the threaded holes, and the front end surface of the pin shaft of the positioning pin (1401) is smooth. Positioning holes (901) that cooperate with the positioning pins (1401) are opened in the center of the side walls at both ends of the U-shaped placement platform (9).

9. The butt welding device for 9Ni steel butt welding according to claim 1, characterized in that: Universal wheels (2) are arranged at the four corners of the lower surface of the base plate (1); mounting holes are arranged at the middle ends of both sides of the lower surface of the base plate (1); support assemblies (3) are arranged at the centers of both ends of the base plate (1); the support assemblies (3) include a Z-shaped side plate (301), a support screw (302) and a support foot (303); the upper plate of the Z-shaped side plate (301) is fixedly connected to the base plate (1); the support screw (302) is threadedly connected to the bottom plate of the Z-shaped side plate (301); the support foot (303) is arranged at the lower end of the support screw (302); the upper end of the support screw (302) passes through the Z-shaped side plate (301) and is provided with a handle.

10. The butt welding device for 9Ni steel butt welding according to claim 1, characterized in that: Two U-shaped placement tables (9) arranged at both ends of the upper end surface of the rotating seat (8) are respectively used to place two 9Ni steel plates (13) to be welded. The two 9Ni steel plates (13) adopt an X-shaped groove (1301), with 30 degrees on the front and back sides respectively, and a gap of 2-4mm between the two pairs. The first welding method adopts argon arc welding single-sided welding and double-sided forming, and then the front and back sides are alternately welded by arc welding until the welding is completed.

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