Gas distribution device and process for automatic shielded welding of inner wall of stainless steel pipe fitting

Abstract

The invention relates to the technical field of stainless steel pipe fitting inner wall welding, in particular to a stainless steel pipe fitting inner wall automatic shielded welding process and a gas distribution device which comprises a welding assembly and a gas distribution assembly. The gas distribution assembly achieves uniform distribution of protective gas through an annular gas cavity, a flow deflector, a flow dividing nozzle and a microwell plate, and the welding assembly adapts to different pipe diameters through an adjusting piece and a sliding supporting piece and is accurately positioned. By means of the gas distribution assembly and the welding assembly, when the welding head conducts welding on the inner wall of the stainless steel pipe fitting, protective gas in the annular gas cavity is guided into the gas channel through the flow deflector, gas flow distribution is further refined through the flow dividing nozzle and the microwell plate, and finally the welding area is evenly covered. By means of the design, the problem that in the prior art, gas distribution is not uniform is effectively solved, and the welding quality is improved. And meanwhile, through cooperation of the adjusting piece and the sliding supporting piece, the welding assembly can be adaptively adjusted according to the inner diameter of the stainless steel pipe fitting.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a gas distribution device and process for automatic shielded welding of the inner wall of a stainless steel pipe. Background Art

[0002] In the manufacturing of stainless steel pipe fittings, the quality of the inner wall weld is a key factor affecting their corrosion resistance and service life. Currently, the industry has developed a number of technologies and equipment specifically for shielded welding of the inner walls of stainless steel pipe fittings. However, these technologies and equipment still have limitations in terms of gas shielding, welding uniformity, and ease of operation. Furthermore, existing gas distribution devices often require complex mechanical structures to achieve uniform gas distribution, which increases manufacturing costs and increases maintenance complexity.

[0003] For example, the Chinese invention patent (application number: 202310677481.9) discloses a "device for detecting the flatness of the edge of insulating glass". Its specification discloses: it includes a fixed base plate, a support rod is fixedly connected to the fixed base plate, a protective top plate is fixedly connected to the top of the support rod, a first spring is fixedly connected to the fixed base plate, a sliding block is fixedly connected to the other end of the first spring, the sliding block is limitedly slidably connected to the fixed base plate, a clamping plate is fixedly connected to the top of the sliding block, an adaptive cleaning component is installed on the clamping plate, an automatic adsorption component and a steering component are installed on the fixed base plate, and the adaptive cleaning component is connected to the automatic adsorption component via a wire rope. This application can not only perform adaptive detection on glass of different sizes, but also conveniently clean the detection area of ​​the glass; the above patent can prove the defects of the existing technology.

[0004] Therefore, we have made improvements to this and proposed an automatic shielded welding gas distribution device and process for the inner wall of stainless steel pipe fittings. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of uneven gas protection, unstable welding quality, complex equipment structure and high manufacturing cost in the existing stainless steel pipe inner wall shielded welding process.

[0006] To achieve the aforementioned objectives and address the aforementioned issues, the present invention provides an automatic shielded welding process and gas distribution device for the inner wall of a stainless steel pipe fitting, comprising a welding assembly and a gas distribution assembly. The welding assembly is provided with a welding head at its center, and a gas distribution assembly is provided outside the welding head. The gas distribution assembly and the welding head work together to provide weld protection for the inner wall of the stainless steel pipe fitting. Adjustments are provided on both sides of the welding assembly, each of which has a sliding support member located within it.

[0007] The gas distribution assembly includes an annular air cavity with several guide vanes fixedly mounted inside. A gas channel is formed between the guide vanes. A diverter nozzle is located at the outlet of the gas channel. A microporous plate is located inside the diverter nozzle, and the microporous plate has multiple evenly distributed through-holes. The annular air cavity evenly transports shielding gas to the outlet of the diverter nozzle through the gas channel, and the microporous plate further refines the gas flow distribution. The welding assembly includes a welding head located in the center of the annular air cavity. When the welding head welds the inner wall of a stainless steel pipe, the gas distribution assembly delivers uniform shielding gas to the welding area.

[0008] As a preferred technical solution of this application, the adjustment member includes an adjustment rod, one end of which is fixedly connected to a limit block, with two limit blocks located on either side of the welding assembly. The other end of the adjustment rod is provided with a threaded section, which cooperates with an external locking nut to adjust the position of the welding assembly.

[0009] As a preferred technical solution of the present application, the welding assembly also includes two support seats fixedly connected to both sides of the welding head, and a guide rod is provided between the two support seats. The guide rod passes through the welding head and is slidably connected to the welding head. The welding head moves along the guide rod to adjust the welding position.

[0010] As a preferred technical solution of the present application, the sliding support member includes a slider slidably connected to the inside of the adjusting member, and a ball bearing is provided at the bottom of the slider. The ball bearing contacts the inner wall of the stainless steel pipe and is used to support the welding assembly and reduce friction.

[0011] As a preferred technical solution of the present application, an air inlet connector is provided on the outside of the annular air cavity, and the air inlet connector is connected to an external air source through a pipeline. A filter is provided inside the air inlet connector for removing impurities in the gas.

[0012] As a preferred technical solution of the present application, the cross-section of the guide plate is arc-shaped, and the arc-shaped surface of the guide plate faces the center direction of the annular air cavity, so that the gas flows along the arc-shaped surface under the action of the guide plate, thereby improving the uniformity of the gas.

[0013] As a preferred technical solution of the present application, the outlet end of the diverter nozzle is provided with a conical expansion portion, and the diameter of the conical expansion portion gradually increases from the inside to the outside, so as to expand the gas coverage range.

[0014] As the preferred technical solution of this application, the thickness of the microporous plate is 1-2mm, the diameter of the through holes on the microporous plate is 0.5-1mm, and the spacing between adjacent through holes is 1-1.5mm, ensuring that the gas can be evenly distributed and the welding quality will not be affected by excessive airflow.

[0015] As a preferred technical solution of the present application, a scale mark is provided in the middle of the adjustment rod, and the scale mark is used to indicate the position of the welding assembly, so that the operator can accurately adjust the position of the welding head.

[0016] As a preferred technical solution of this application, a spring is provided on the top of the slider, and the two ends of the spring are fixedly connected to the slider and the inner wall of the adjusting member respectively. The elastic force of the spring makes the slider always close to the inner wall of the stainless steel pipe.

[0017] As a preferred technical solution of the present application, a sealing ring is provided on the inner side of the annular air cavity, and the sealing ring fits tightly with the outer side of the guide plate to prevent gas leakage.

[0018] As a preferred technical solution of this application, a stainless steel pipe inner wall automatic shielded welding process includes the following steps: S1. Device pretreatment: Assemble the welding assembly and the gas distribution assembly, and adjust the extension length of the sliding support by adjusting the adjustment rod of the adjustment member so that the ball fits the inner wall of the stainless steel pipe; S2. Gas parameter setting: Connect argon gas through the gas inlet connector, adjust the gas source pressure to 0.2-0.3MPa, control the gas flow rate at 8-12L / min, and filter it into the annular air cavity; S3. Welding positioning: Push the device to the welding position, and position the welding head by adjusting the scale mark on the rod so that the alignment deviation between the welding head and the weld is ≤1mm, and the distance between the micro-hole plate and the welding area is 5-8mm; S4. Pre-flow of shielding gas: Open the gas source 3-5 seconds in advance, so that the shielding gas is guided by the guide plate, diffused by the diverter nozzle and refined by the micro-porous plate, forming a stable gas curtain in the welding area; S5, automatic welding: Start the welding head and move the welding head along the guide rod at a speed of 50-100mm / min. At the same time, the position of the movable plate is adjusted in real time through the extension rod to keep the tension in the welding area at 20-30N. The air curtain pressure is continuously monitored during the welding process. S6. Post-weld treatment: After welding is completed, delay 5-8 seconds to turn off the gas source. After the protective gas completely covers the molten pool and cools down, exit the device and clean the inner wall of the pipe.

[0019] As a preferred technical solution of the present application, in S5, the welding head adopts a pulse arc welding mode; when the inner diameter of the pipe changes, the gap between the microporous plate (8) and the inner wall of the pipe is maintained at 3-5 mm through the spring adaptive adjustment of the sliding support.

[0020] Compared with the prior art, the present invention has the following beneficial effects: By setting up the gas distribution assembly and welding assembly, when the welding head is welding on the inner wall of the stainless steel pipe, the protective gas in the annular air cavity is guided into the gas channel through the guide plate, and the airflow distribution is further refined by the diverter nozzle and the microporous plate, and finally the welding area is evenly covered. This design effectively solves the problem of uneven gas distribution in the prior art and improves the welding quality. At the same time, through the cooperation of the adjustment part and the sliding support part, the welding assembly can be adaptively adjusted according to the inner diameter of the stainless steel pipe, which simplifies the operation process and reduces the manufacturing cost and maintenance difficulty of the equipment. In addition, the design of the microporous plate not only refines the airflow distribution, but also avoids the interference of the welding process caused by excessively fast airflow, further improving the stability and reliability of welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention, showing the layout of the welding assembly and the gas distribution assembly and their mutual relationship.

[0022] Figure 2 Schematic diagram of the structure of the welding assembly.

[0023] Figure 3 A cross-sectional view of the gas distribution assembly.

[0024] Figure 4 It is a structural diagram of the adjusting member and the sliding support member.

[0025] The accompanying drawings are numbered as follows: 1. Welding assembly; 2. Gas distribution assembly; 3. Welding head; 4. Annular air cavity; 5. Guide vane; 6. Gas channel; 7. Diverter nozzle; 8. Microporous plate; 9. Adjustment part; 10. Sliding support; 11. Adjustment rod; 12. Limit block; 13. Slider; 14. Ball bearing; 15. Air inlet connector; 16. Filter; 17. Support seat; 18. Guide rod. DETAILED DESCRIPTION

[0026] The present invention provides a stainless steel pipe inner wall automatic shielded welding gas distribution device, the overall structure of which is as follows: Figure 1-4 As shown, the welding assembly 1 includes a welding head 3 and a gas distribution assembly 2. A welding head 3 is located at the center of the welding assembly 1, and a gas distribution assembly 2 is installed outside the welding head 3. The gas distribution assembly 2 works in conjunction with the welding head 3 to provide weld protection for the inner wall of the stainless steel pipe. Adjusters 9 are located on either side of the welding assembly 1, and sliding supports 10 are installed inside the adjusting members 9. The sliding supports 10 are used to support the welding assembly 1 and reduce friction.

[0027] The specific structure of the gas distribution component 2 is as follows Figure 2-3As shown, the core portion of the device is an annular air cavity 4, with several guide vanes 5 fixedly mounted inside the annular air cavity 4. A gas channel 6 is formed between the guide vanes 5. The outlet of the gas channel 6 is connected to a diverter nozzle 7, and a microporous plate 8 is located inside the diverter nozzle 7. The microporous plate 8 has multiple evenly distributed through-holes. The shielding gas in the annular air cavity 4 is transported to the diverter nozzle 7 through the gas channel 6. The microporous plate 8 further refines the gas flow distribution and evenly covers the welding area. The outer side of the annular air cavity 4 is provided with an air inlet connector 15, which is connected to an external gas source via a pipeline. The interior of the air inlet connector 15 is equipped with a filter 16 to remove impurities in the gas. The guide vanes 5 have an arc-shaped cross-section, with the arc surface facing the center of the annular air cavity 4. This allows the gas to flow along the arc surface under the action of the guide vanes 5, thereby improving the uniformity of the gas. The outlet end of the diverter nozzle 7 is provided with a tapered expansion portion, the diameter of which gradually increases from the inside to the outside, which is used to expand the gas coverage area. The thickness of the microporous plate 8 is 1-2 mm, the diameter of the through holes is 0.5-1 mm, and the spacing between adjacent through holes is 1-1.5 mm, ensuring that the gas can be evenly distributed and the welding quality will not be affected by excessive airflow.

[0028] The specific structure of the regulating member 9 is as follows: Figure 4 As shown, the adjusting member 9 includes an adjusting rod 11, one end of which is fixedly connected to a limit block 12, and the two limit blocks 12 are respectively located on both sides of the welding assembly 1. A threaded section is provided at the other end of the adjusting rod 11, and the threaded section is used in conjunction with an external locking nut to adjust the position of the welding assembly 1. A scale mark is provided in the middle of the adjusting rod 11, and the scale mark is used to indicate the position of the welding assembly 1, so that the operator can accurately adjust the position of the welding head 3. The sliding support member 10 includes a slider 13 slidably connected to the inside of the adjusting member 9, and a ball 14 is provided at the bottom of the slider 13. The ball 14 contacts the inner wall of the stainless steel pipe fitting to support the welding assembly 1 and reduce friction. A spring is provided at the top of the slider 13, and the two ends of the spring are respectively fixedly connected to the slider 13 and the inner wall of the adjusting member 9. The elastic force of the spring ensures that the slider 13 always clings to the inner wall of the stainless steel pipe fitting.

[0029] The specific structure of the welding assembly 1 is as follows Figure 2 As shown, the welding assembly 1 includes two support seats 17 respectively fixedly connected to the two sides of the welding head 3, and a guide rod 18 is provided between the two support seats 17. The guide rod 18 passes through the welding head 3 and is slidably connected to the welding head 3. The welding head 3 moves along the guide rod 18 to adjust the welding position.

[0030] A sealing ring is provided on the inner side of the annular air cavity 4 , and the sealing ring is in close contact with the outer side of the guide plate 5 to prevent gas leakage.

[0031] During operation, the welding assembly 1 and gas distribution assembly 2 are first assembled, and then the entire assembly is inserted into the inner wall of the stainless steel pipe to be welded. The position of the welding assembly 1 is adjusted using the adjustment rod 11 of the adjustment member 9, so that the welding head 3 is aligned with the area to be welded. The scale markings on the adjustment rod 11 assist the operator in precisely controlling the position of the welding head 3. The slider 13 in the sliding support 10, due to the elastic force of the spring, adheres tightly to the inner wall of the stainless steel pipe, while the ball bearing 14 reduces friction, ensuring that the welding assembly 1 moves smoothly along the inner wall of the stainless steel pipe.

[0032] During welding, an external gas source delivers shielding gas into the annular air cavity 4 through the air inlet connector 15. The shielding gas passes through the filter 16 to remove impurities and then enters the annular air cavity 4. The gas in the annular air cavity 4 enters the gas channel 6 under the guidance of the guide vane 5, and then the air flow distribution is further refined by the diverter nozzle 7 and the microporous plate 8. The conical extension of the diverter nozzle 7 expands the gas coverage area, and the through holes in the microporous plate 8 ensure that the gas is evenly distributed, avoiding interference with the welding process due to excessively fast airflow. When the welding head 3 is welding on the inner wall of the stainless steel pipe, the gas distribution assembly 2 delivers uniform shielding gas to the welding area, thereby effectively protecting the welding area from oxidation or other external factors.

[0033] The entire device is designed with the practical needs of stainless steel pipe interior welding in mind. The multi-stage gas flow refinement of the gas distribution assembly 2 and the flexible adjustment capabilities of the welding assembly 1 address the existing issues of uneven gas shielding, unstable welding quality, complex equipment structure, and high manufacturing costs. The various components of the device function through mechanical connections and coordination, resulting in a simple and easy-to-maintain structure suitable for welding the interior walls of stainless steel pipes of various specifications.

[0034] In order to better enable relevant personnel in this technical field to fully understand and implement the present invention, the specific implementation principles of the present invention are supplemented below in combination with specific application scenarios.

[0035] First, assemble the welding assembly 1 and gas distribution assembly 2 according to the design requirements, ensuring that all components are tightly and securely connected. Next, insert the entire assembly into the inner wall of the stainless steel pipe to be welded. The balls 14 in the sliding support 10 now contact the inner wall of the stainless steel pipe, and the spring force keeps the slider 13 in close contact with the inner wall of the pipe, providing stable support for the entire assembly and reducing friction. The adjustment rod 11 in the adjustment member 9 is secured to the sides of the welding assembly 1 by stoppers 12 at each end. The operator can precisely adjust the position of the welding head 3 using the scale markings on the adjustment rod 11 to align it with the area to be welded.

[0036] Before the welding starts, the external gas source delivers the shielding gas to the annular gas cavity 4 through the gas inlet joint 15, and the gas enters the annular gas cavity 4 after removing impurities through the filter screen 16. The flow guide vane 5 in the annular gas cavity 4 has an arc-shaped cross section, and the arc-shaped surface thereof faces the center direction of the annular gas cavity 4, so that the gas flows along the arc-shaped surface, thereby improving the uniformity of the gas. The gas passage 6 between the flow guide vanes 5 guides the gas to the flow divider nozzle 7, and the outlet end of the flow divider nozzle 7 is provided with a tapered expansion portion, and the diameter of the tapered expansion portion gradually increases from inside to outside, thereby further expanding the coverage range of the gas. A plurality of through holes are formed in the microporous plate 8 on the inner side of the flow divider nozzle 7, the diameter of the through holes is 0.5-1mm, and the spacing between adjacent through holes is 1-1.5mm. This design ensures that the gas can be uniformly distributed and will not interfere with the welding process due to excessive gas flow.

[0037] During the welding process, the welding head 3 moves along the guide rod 18 to adjust the welding position. When the welding head 3 is welding on the inner wall of the stainless steel pipe, the gas distribution assembly 2 delivers uniform shielding gas to the welding area, effectively protecting the welding area from oxidation or other external factors.

[0038] In actual application, if it is necessary to adjust the position of the welding head 3, the operator can fine-tune it through the adjusting rod 11 of the adjusting piece 9. The threaded section of the adjusting rod 11 is used in cooperation with the external locking nut, and the position of the welding assembly 1 can be adjusted by rotating the locking nut, and at the same time, the scale mark on the adjusting rod 11 can assist the operator to accurately control the position of the welding head 3. The sliding block 13 in the sliding support 10 always maintains contact with the inner wall of the stainless steel pipe through the elastic force of the spring, and the design of the ball 14 reduces the friction force when the device moves on the inner wall of the pipe, thereby ensuring that the welding assembly 1 can run smoothly.

[0039] The design of the whole device realizes the uniform distribution of the shielding gas through a multi-stage gas flow refinement mechanism. The gas in the annular gas cavity 4 flows along the arc-shaped surface under the action of the flow guide vane 5, thereby improving the initial uniformity of the gas; the gas passage 6 guides the gas to the flow divider nozzle 7, and the tapered expansion portion of the flow divider nozzle 7 further expands the coverage range of the gas; and the through holes on the microporous plate 8 finally refine the gas flow distribution, thereby ensuring that the gas can uniformly cover the welding area. In addition, the sealing ring effectively prevents gas leakage.

[0040] The application also discloses a stainless steel pipe inner wall automatic protection welding process, which comprises the following steps: S1, device pretreatment: assemble the welding assembly 1 and the gas distribution assembly 2, adjust the extension length of the sliding support 10 through the adjusting rod 11 of the adjusting piece 9, make the ball 14 fit the inner wall of the stainless steel pipe, and control the spring compression amount to be 2-3mm, so as to ensure that the sliding resistance of the device in the pipe is ≤5N; S2. Gas parameter setting: Connect argon gas with a purity of ≥99.99% through the gas inlet connector 15, adjust the gas source pressure to 0.2-0.3 MPa, control the gas flow rate to 8-12 L / min, and filter it through the filter 16 before entering the annular gas cavity 4; S3. Welding positioning: Push the device to the welding position, and position the welding head 3 by adjusting the scale mark of the rod 11 so that the alignment deviation between the welding head 3 and the weld is ≤1mm, and at the same time ensure that the distance between the micro-plate 8 and the welding area is 5-8mm; S4, shielding gas pre-flow: open the gas source 3-5 seconds in advance, so that the shielding gas is guided by the guide plate 5, diffused by the diverter nozzle 7 and refined by the micro-porous plate 8, forming a stable gas curtain in the welding area. The coverage of the gas curtain is ≥ 1.5 times the diameter of the welding area; S5. Automatic welding: Start the welding head 3 and move it along the guide rod 18 at a speed of 50-100 mm / min. At the same time, the position of the movable plate 306 is adjusted in real time by the push rod to keep the tension in the welding area at 20-30N. During the welding process, the air curtain pressure is continuously monitored and the fluctuation range is ≤±0.02MPa. S6. Post-weld treatment: After welding is completed, delay 5-8 seconds to turn off the gas source. After the protective gas completely covers the molten pool and cools down, exit the device and clean the inner wall of the pipe.

[0041] The automatic shielded welding process for the inner wall of a stainless steel pipe according to claim 9 is characterized in that, in S5, the welding head 3 adopts a pulse arc welding mode with a pulse frequency of 50-100 Hz, a peak current of 120-150 A, a base current of 40-60 A, and an arc voltage maintained at 18-22 V; when the inner diameter of the pipe changes, the elastic coefficient of the spring of the sliding support 10 is adaptively adjusted to 80-100 N / m to ensure that the gap between the microplate 8 and the inner wall of the pipe is always maintained at 3-5 mm, and the gas flow rate uniformity error is ≤5% By combining the above steps and principles, the present invention solves the existing problems of uneven gas shielding, unstable welding quality, complex equipment structure, and high manufacturing costs. The various components of the device function through mechanical connections and coordination, resulting in a simple and easy-to-maintain structure suitable for welding the interior walls of stainless steel pipes of various specifications.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gas distribution device for automatic shielded welding of the inner wall of a stainless steel pipe, characterized in that: The invention comprises a welding assembly (1) and a gas distribution assembly (2), wherein a welding head (3) is provided at the center of the welding assembly (1), and a gas distribution assembly (2) is provided on the outside of the welding head (3), and welding protection of the inner wall of the stainless steel pipe is completed through the coordinated action of the gas distribution assembly (2) and the welding head (3), and an adjusting member (9) is provided on both sides of the welding assembly (1), and a sliding support member (10) is provided inside the adjusting member (9).

2. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 1, characterized in that: The gas distribution assembly (2) comprises an annular air cavity (4), a plurality of guide vanes (5) are fixedly mounted on the inner side of the annular air cavity (4), a gas channel (6) is formed between the plurality of guide vanes (5), a diverter nozzle (7) is provided at the outlet end of the gas channel (6), a microporous plate (8) is provided on the inner side of the diverter nozzle (7), and a plurality of evenly distributed through holes are opened on the microporous plate (8).

3. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 2, characterized in that: The adjusting member (9) comprises an adjusting rod (11), one end of the adjusting rod (11) is fixedly connected to a limit block (12), two limit blocks (12) are respectively located on both sides of the welding assembly (1), and the other end of the adjusting rod (11) is provided with a threaded section, and the threaded section is used in conjunction with an external locking nut to adjust the position of the welding assembly (1).

4. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 1, characterized in that: The welding assembly (1) further comprises two support seats (17) respectively fixedly connected to both sides of the welding head (3); a guide rod (18) is provided between the two support seats (17); the guide rod (18) passes through the welding head (3) and is slidably connected to the welding head (3); the welding head (3) moves along the guide rod (18) to adjust the welding position.

5. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 1, characterized in that: The sliding support member (10) includes a slider (13) slidably connected to the inside of the adjusting member (9), and a ball (14) is provided at the bottom of the slider (13). The ball (14) contacts the inner wall of the stainless steel pipe and is used to support the welding assembly (1) and reduce friction.

6. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 2, characterized in that: An air inlet connector (15) is provided on the outside of the annular air cavity (4), the air inlet connector (15) is connected to an external air source via a pipeline, and a filter screen (16) is provided inside the air inlet connector (15).

7. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 2, characterized in that: The outlet end of the diversion nozzle (7) is provided with a conical expansion portion, the diameter of which gradually increases from the inside to the outside. The thickness of the microporous plate (8) is 1 to 2 mm, the diameter of the through holes on the microporous plate (8) is 0.5 to 1 mm, and the spacing between adjacent through holes is 1 to 1.5 mm.

8. The automatic shielded welding gas distribution device for the inner wall of a stainless steel pipe according to claim 5, characterized in that: A spring is provided on the top of the slider (13), and both ends of the spring are fixedly connected to the slider (13) and the inner wall of the adjusting member (9), respectively. A scale mark is provided in the middle of the adjusting rod (11).

9. A stainless steel pipe inner wall automatic shielded welding process, using the stainless steel pipe inner wall automatic shielded welding gas distribution device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Device pretreatment: Assemble the welding assembly (1) and the gas distribution assembly (2), and adjust the extension length of the sliding support member (10) through the adjustment rod (11) of the adjustment member (9) so that the ball (14) fits the inner wall of the stainless steel pipe; S2. Gas parameter setting: connect argon gas through the gas inlet connector (15), adjust the gas source pressure to 0.2-0.3 MPa, control the gas flow rate to 8-12 L / min, and filter it through the filter (16) before entering the annular gas cavity (4); S3, welding positioning: push the device to the welding position, and position the welding head (3) by adjusting the scale mark of the rod (11) so that the alignment deviation between the welding head (3) and the weld is ≤1mm, and the distance between the micro-plate (8) and the welding area is 5-8mm; S4, shielding gas pre-flow: open the gas source 3-5 seconds in advance, so that the shielding gas is guided by the guide plate (5), diffused by the diverter nozzle (7) and refined by the microporous plate (8), forming a stable gas curtain in the welding area; S5, automatic welding: start the welding head (3), move the welding head along the guide rod (18) at a speed of 50-100 mm / min, and adjust the position of the movable plate (306) in real time through the top extension rod to keep the tension in the welding area at 20-30N. Continuously monitor the air curtain pressure during the welding process; S6. Post-weld treatment: After welding is completed, delay 5-8 seconds to turn off the gas source. After the protective gas completely covers the molten pool and cools down, exit the device and clean the inner wall of the pipe.

10. The automatic shielded welding process for the inner wall of a stainless steel pipe according to claim 9, characterized in that: In S5, the welding head (3) adopts a pulse arc welding mode; when the inner diameter of the pipe changes, the gap between the micro-porous plate (8) and the inner wall of the pipe is maintained at 3-5 mm through the spring adaptive adjustment of the sliding support (10).

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