Pipe inner hole gas shielded welding chuck and pipe inner hole gas shielded welding method

Abstract

The invention discloses an in-pipe inner hole gas shielded welding chuck and an in-pipe inner hole gas shielded welding method, the in-pipe inner hole gas shielded welding chuck comprises a basic part, clamping seats, flat bushings, air passage bushings and an air inlet pipe, the basic part is in threaded connection with a stud, one clamping seat is fixedly connected with the basic part, the other clamping seat is used for abutting against the stud, the two flat bushings are respectively connected with the two clamping seats, and the air passage bushings are connected with the air inlet pipe. The two air passage bushings are connected with the two clamping seats respectively, each air passage bushing and the corresponding clamping seat define an air passage, the air passages are communicated with the inner sides of the air passage bushings, the air inlet pipes are communicated with the air passages and used for inputting inert gas, and under the condition that the double-screw bolt abuts against the two clamping seats to be closed, the two air passage bushings and the two clamping seats are closed. The first pipe fitting arranged between the two flat bushings in a penetrating mode is right opposite to the second pipe fitting arranged between the two airway bushings in a penetrating mode. The welding process of one-side welding and double-side forming of pipe orifice butt joint inner hole welding can be carried out, the labor intensity of constructors is relieved, original manual outer side welding construction is changed into machine automatic inner hole welding construction, the working efficiency is effectively improved, and the working period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of shielded welding, and in particular to a gas shielded welding chuck for inner-holes in pipes and a gas shielded welding method for inner-holes in pipes. Background Art

[0002] The inner hole welding process has a wide range of application scenarios. For example, the 24 inlet and outlet water pipes of a certain product's main heat exchanger should be welded to the corresponding pipe openings on the side wall of the pressure vessel to complete the on-site installation of the main heat exchanger. However, due to space limitations, the welding gun can only be inserted from the pipe opening on the side of the outer wall of the pressure vessel to weld the 24 pipes one by one to weld the 24 on-site butt welds of the main heat exchanger. The inner hole welding of the main heat exchanger is a deep hole, full position, full blind and non-grooved helium-argon mixed gas shielded non-melting electrode arc welding.

[0003] The wall thickness difference, misalignment and gap of the pipe joint will affect the quality of the inner hole welding. The welds of the inner hole welding workpieces are mostly concave and convex, and some exceed the appearance inspection requirements. It is very difficult to pass the film inspection. Therefore, after the inner hole welding process parameters are optimized and finalized, the main difficulty in the on-site implementation of the inner hole welding is the quality control of the butt installation of the main heat exchanger pipe mouth and the pressure vessel pipe mouth. When the pipe mouth is butt-jointed, the welding process is carried out inside the pipe, and a special protective gas hood needs to be designed on the outside of the pipe mouth for back protection.

[0004] Therefore, it is necessary to design a chuck fixture that can not only meet the requirements of pipe mouth butt assembly adjustment accuracy, but also provide reliable inert gas protection for the single-sided welding and double-sided forming process of the pipe mouth weld. Summary of the invention

[0005] In order to solve the above problems, the present application provides a pipe inner hole gas shielded welding chuck and a pipe inner hole gas shielded welding method.

[0006] The present application provides a gas shielded welding chuck for an inner hole in a pipe, comprising a base part, a clamp seat, a flat bushing, an airway bushing and an inlet pipe, the base part being threadedly connected with a stud, two clamp seats being relatively provided, one clamp seat being fixedly connected to the base part, and the other clamp seat being used to abut against the stud, the flat bushing being provided with two lobes, the two lobes of the flat bushing being respectively connected to the two clamp seats, the airway bushing being provided with two lobes, the two lobes of the airway bushing being respectively connected to the two clamp seats, the airway bushing being spaced apart from the flat bushing, and each lobe of the airway bushing and the clamp seat being enclosed to form an airway, the airway being connected to the inner side of the airway bushing, at least two inlet pipes being provided, the inlet pipes being connected to a side of the clamp seat facing away from the airway bushing and being connected to the airway, the inlet pipes being used to input inert gas, wherein, under the condition that the stud is pressed until the two clamp seats are closed, the first pipe fitting passed through the two lobes of the flat bushing is directly opposite to the second pipe fitting passed through the two lobes of the airway bushing.

[0007] In some embodiments, the air duct is connected to the inner side of the air duct bushing and forms an air port. When the stud is pressed until the two clamp seats are closed, the first pipe fitting passed through the two halves of the flat bushing is directly opposite to the second pipe fitting passed through the two halves of the air duct bushing, and the pipe port gap formed by the first pipe fitting and the second pipe fitting is directly opposite to the air port.

[0008] In some embodiments, each flat bushing is provided with at least two first protrusions located on the inner side and distributed along the circumferential direction of the flat bushing, and each airway bushing is provided with at least two second protrusions located on the inner side and distributed along the circumferential direction of the airway bushing. When the stud is pressed to close the two clamp seats, the first protrusion contacts the first pipe fitting and the second protrusion contacts the second pipe fitting.

[0009] In some embodiments, an axial end of the airway bushing close to the flat bushing is spaced apart from the clamp seat;

[0010] The airway is distributed along the annular direction of the airway bushing, and sealing plates are installed at both ends of the annular direction of the airway, and the sealing plates are sealed and connected with the airway bushing and the support;

[0011] A filter is arranged in the air passage, and the filter is spread between the air port and the air inlet pipe.

[0012] In some embodiments, the clamp seat is an arc-shaped structure, and the central angle of the arc-shaped structure is less than 180°.

[0013] In some embodiments, the base member is a C-shaped clamp, the C-shaped clamp includes a first arc segment, a straight segment, and a second arc segment, an arcuate end of the first arc segment is connected to one end of the straight segment, and the other end of the straight segment is connected to an arcuate end of the second arc segment;

[0014] The two clamping seats are respectively a first clamping seat and a second clamping seat, the first clamping seat is closely connected to the inner side of the first arc section, and the first clamping seat is connected to one end of the straight section, the stud is threadedly installed on the second arc section, and the stud is used to press the second clamping seat to be joined together with the first clamping seat.

[0015] In some embodiments, the second clamp seat is connected to a top block located on the outside, the top block is distributed along the axial direction of the second clamp seat, and the top block is used to contact the stud.

[0016] In some embodiments, the top block is provided with an alignment hole, which is provided on a side of the top block away from the second clamp seat, and the alignment hole is used for the stud to pass through so as to align the axial ends of the two clamp seats when the stud is pressed to close the two clamp seats.

[0017] In some embodiments, the in-tube gas shielded welding chuck is further provided with a gas cylinder filled with inert gas, and the gas cylinder is connected to the air inlet pipe through a hose.

[0018] A method for gas shielded welding of inner holes in pipes, using the above-mentioned gas shielded welding chuck for inner holes in pipes, the method comprising:

[0019] The first pipe fitting is fixedly mounted on the head of the inner hole welding machine;

[0020] Place the first pipe installed on the machine head close to the second pipe to be butted and align the pipe ends;

[0021] Put two clamps on the first pipe fitting and the second pipe fitting and tighten the studs until the pipe opening is clamped;

[0022] After the air passage is filled with inert gas, the gun head of the inner hole welding machine rotates around the first pipe fitting for one circle to complete the welding of the butt joint between the first pipe fitting and the second pipe fitting.

[0023] The beneficial effects of the present application are as follows: a gas shielded welding chuck for inner hole in pipe is provided, comprising a base, a clamp seat, a flat bushing, an airway bushing and an air inlet pipe, the clamp seat is divided into two parts, one upper and one lower, the first clamp seat is installed on the base, the second clamp seat is pressed against the first clamp seat by a stud on the base, two flat bushings distributed in pairs are installed on the inner sides of the two clamp seats, the first pipe fitting to be welded is spatially positioned by the two flat bushings distributed in pairs, the two airway bushings distributed in pairs are installed on the inner sides of the two clamp seats, the second pipe fitting to be welded is spatially positioned by the two airway bushings distributed in pairs, The first pipe fitting inserted between the two flat bushings is directly opposite to the second pipe fitting inserted between the two airway bushings, and each airway bushing is enclosed with the clamp seat to form an airway, the airway is connected to the inner side of the airway bushing, the air inlet pipe is connected to the side of the clamp seat away from the airway bushing and is connected to the airway, and inert gas is input into the airway through the air inlet pipe, and inert gas is provided as a protective gas for the pipe butt joint weld when the first pipe fitting and the second pipe fitting are butt-welded; the gas shielded welding chuck for in-pipe holes of the present application is used, and the two pipe openings to be welded are accurately welded by manually installing the upper and lower clamp seats and locking them. The invention can be fixed to achieve the purpose of precise assembly of adjusting concentricity, straightness and misalignment of pipe wall, and form circumferential precise gas protection at the joint weld, so as to achieve high-precision welding of pipe butt joint, and realize the welding process of single-sided welding and double-sided forming of inner hole welding of pipe butt joint, including but not limited to the realization of helium-argon mixed gas shielded non-melting electrode arc welding for deep hole, full position, full blind and non-groove inner hole welding of main heat exchanger; the welding process of single-sided welding and double-sided forming of inner hole welding of pipe butt joint by using the pipe inner hole gas shielded welding chuck of the present application can reduce the labor intensity of construction personnel, and the previous manual outer side welding can be used for the inner hole welding of pipe butt joint. The welding construction is changed to automatic inner hole welding construction by machines, which effectively improves the work efficiency and shortens the operation cycle. In addition, the application scheme has the characteristics of simple structure, low manufacturing difficulty, saving human resources, low cost and small investment, and is very suitable for the welding process of single-sided welding and double-sided forming of the inner hole welding of the pipe butt. It provides a strong reference for the butt welding of new varieties and specifications of medium and small diameter safety-grade pipelines, copper alloy pipelines, stainless steel and duplex stainless steel pipelines, etc., to achieve safe and precise welding processes and automated welding technology, which is convenient for large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0025] Figure 1 A schematic diagram of a radial cross section of a gas shielded welding chuck for inner hole of a pipe provided in the present application;

[0026] Figure 2 A schematic diagram of an axial cross section of a gas shielded welding chuck for in-pipe holes provided in the present application.

[0027] The accompanying drawings are marked with: 10-base part, 11-stud, 121-first arc segment, 122-straight segment, 123-second arc segment, 20-clamp seat, 21-first clamp seat, 22-second clamp seat, 23-top block, 30-flat bushing, 31-first protrusion, 40-air duct bushing, 41-air duct, 411-air port, 412-filter screen, 42-second protrusion, 43-sealing plate, 50-intake pipe, L1-clamp seat closing gap, L2-air port span. DETAILED DESCRIPTION

[0028] The 24 inlet and outlet water pipes of a certain product's main heat exchanger should be welded to the corresponding pipe openings on the side wall of the pressure vessel to complete the on-site installation of the main heat exchanger. However, due to space limitations, the 24 on-site butt welds of the main heat exchanger can only be inserted into the welding gun from the pipe opening on the side of the outer wall of the pressure vessel, and welded one by one in the 24 pipes. This process is called the main heat exchanger tube inner hole welding process. To solve the technical problems of product pipeline welding process, mainly for new varieties and specifications of materials such as safety-grade pipelines, copper alloy pipelines, stainless steel and duplex stainless steel pipelines, welding process research is carried out around safety, precision welding process, automated welding technology and process improvement, to form applicable welding technology and improve the technical level and efficiency of pipeline welding.

[0029] The research on the full-position and horizontal rolling automatic welding process of stainless steel safety-grade pipelines for a certain product. The purpose of this patent is to serve product construction, solve the welding problems of product pipeline construction, improve and enhance pipeline welding technology, develop new pipeline welding technology, and make the factory's pipeline welding develop in the direction of high-efficiency, high-quality automation.

[0030] The inner hole welding of the main heat exchanger is deep hole, full position, full blind and non-grooved helium-argon mixed gas shielded non-melting electrode arc welding (TIG). The welding parameters of the main workpieces of the product are: φ57×3.8 stainless steel pipe (or duplex stainless steel pipe), welding pipe wall thickness 3.8mm, depth 260mm.

[0031] The difficulty of inner hole welding is that the wall thickness difference, misalignment and gap of the inner hole welding pipe joint will affect the quality of the inner hole welding. The welds of inner hole welding workpieces are mostly concave and convex, and some exceed the appearance inspection requirements, and it is very difficult to pass the film inspection. After many scientific research experiments, the inventor recommends that the pipe mouth size and docking assembly parameters should be controlled as follows: wall thickness 3.8±0.1mm, misalignment less than 0.5mm and gap less than 0.5mm.

[0032] After the inner hole welding process parameters are optimized and finalized, the main difficulty in the on-site implementation of the inner hole welding is the quality control of the butt joint installation of the main heat exchanger pipe mouth and the pressure vessel pipe mouth. When the pipe mouth is butt jointed, the welding process is carried out inside the pipe, and a special protective gas hood needs to be designed on the outside of the pipe mouth for back protection.

[0033] The protective gas hood should have the characteristics of good protection effect and easy installation. Therefore, it is necessary to design a pipe inner hole gas shielded welding chuck that can not only meet the requirements of pipe mouth butt assembly adjustment accuracy, but also provide reliable inert gas protection for the single-sided welding and double-sided forming process of the pipe mouth weld.

[0034] In order to achieve the above-mentioned purpose, the present application discloses a pipe inner hole gas shielded welding chuck, hereinafter referred to as the chuck, please refer to Figure 1 and Figure 2 The chuck includes a base 10, a clamp seat 20, a flat bushing 30, an airway bushing 40 and an air inlet pipe 50, and is mainly divided into an upper and lower half, the clamp seat 20 is provided with two relatively, the flat bushing 30 is provided with two petals, the airway bushing 40 is provided with two petals, and the air inlet pipe 50 is provided with at least two. Figure 1 and Figure 2 The two components are distributed in upper and lower parts.

[0035] The base 10 is the installation base of the chuck. The two clamping seats 20 are the first clamping seat 21 and the second clamping seat 22. The first clamping seat 21 is fixedly connected to the base 10. The stud 11 is threadedly connected to the base 10. The relative position of the stud 11 on the base 10 can be adjusted. The second clamping seat 22 is used to abut against the stud 11. The second clamping seat 22 is pressed against the first clamping seat 21 through the stud 11 on the base 10. When the stud 11 presses the second clamping seat 22 against the first clamping seat 21, the second clamping seat 22 and the first clamping seat 21 are in a closed state. Please refer to Figure 1 , Figure 1 There is a clamp seat closing gap L1, which is controlled at about 0.3 mm, for example, 0.3 mm±0.05 mm, so the central angle between the first clamp seat 21 and the second clamp seat 22 is less than and close to 180°.

[0036] Please refer to Figure 1 and Figure 2 Two flat bushings 30 are installed in pairs inside the two clamping seats 20. The two flat bushings 30 are connected to the two clamping seats 20 respectively. The flat bushings 30 are used to directly contact the first pipe to be welded. The first pipe to be welded is spatially positioned by the two flat bushings 30. Since the flat bushings 30 are components that directly contact the first pipe, the inner diameter of the flat bushings 30 is equal to the outer diameter of the first pipe. Figure 1 The clamp seat shown closes the gap L1, so the center angle of the single-petal flat bushing 30 is less than and close to 180°.

[0037] Please refer to Figure 1 and Figure 2 , two-petal airway bushings 40 distributed in pairs are installed on the inner sides of the two clamp seats 20, the two-petal airway bushings 40 are connected to the two clamp seats 20 respectively, the airway bushings 40 and the flat bushings 30 are spaced apart from each other, the flat bushings 30 are located on one axial side of the clamp seat 20, and the airway bushings 40 are located on the other axial side of the clamp seat 20. The airway bushings 40 are used to directly contact the second pipe fitting to be welded, and the second pipe fitting to be welded is spatially positioned by the two-petal airway bushings 40 distributed in pairs. Since the airway bushings 40 are components that are in direct contact with the second pipe fitting, the inner diameter of the airway bushings 40 is equal to the outer diameter of the second pipe fitting. Due to the existence of Figure 1 The clamp seat shown closes the gap L1, so the central angle of the airway bushing 40 is less than and close to 180°.

[0038] The particularity of the airway bushing 40 is that, please refer to Figure 1 and Figure 2 Each valve of the airway bushing 40 and the clamp seat 20 enclose an airway 41, and the airway 41 is connected to the inner side of the airway bushing 40, and the airway 41 forms an air port 411 on the inner side of the airway bushing 40. Figure 2 The air port span L2 is shown in FIG. 4 , which refers to the axial dimension of the air port 411 along the clamp seat 20. The air port span L2 is controlled to be about 1 mm, for example, 1 mm ± 0.5 mm. The air inlet pipe 50 is connected to the side of the clamp seat 20 away from the airway bushing 40, and the air inlet pipe 50 is connected to the airway 41. The inert gas is input into the airway 41 through the air inlet pipe 50, and the inert gas flows to the outer peripheral side of the first pipe fitting and the second pipe fitting through the air port 411, and inert gas is provided to the back of the butt joint when the first pipe fitting and the second pipe fitting are butt-jointed with the inner hole welding, and necessary inert gas protection is provided to the outer side of the pipe fitting during the welding process.

[0039] In the present application, the upper and lower clamps 20 are manually installed and locked to accurately fix the two pipe openings to be welded. Figure 1 When the two clamp seats 20 are pressed together, the first pipe fitting inserted between the two flat bushings 30 is aligned with the second pipe fitting inserted between the two airway bushings 40, thereby achieving the purpose of precise assembly by adjusting the key concentricity, straightness and misalignment of the first and second pipe fittings, and forming circumferential precise gas protection at the joint weld, achieving high-precision welding of pipe butt joints, and realizing the welding process of single-sided welding and double-sided forming of the inner hole welding of the pipe butt joint, including but not limited to the realization of helium-argon mixed gas shielded non-melting electrode arc welding for deep hole, full position, full blind and non-beveled inner hole welding of the main heat exchanger.

[0040] The use of the gas shielded welding chuck for the inner hole of the pipe in the present application for the single-sided welding and double-sided forming welding process of the pipe mouth butt inner hole welding reduces the labor intensity of the construction personnel, and changes the previous manual outer hole welding construction into machine-automatic inner hole welding construction, effectively improving the work efficiency and shortening the operation cycle.

[0041] In addition, the application scheme has the characteristics of simple structure, low manufacturing difficulty, saving human resources, and has the advantages of low cost and small investment. It is very suitable for application in the welding process of single-sided welding and double-sided forming of pipe butt inner hole welding. It provides a strong reference for the butt welding of new varieties and new specifications of medium and small diameter safety-grade pipelines, copper alloy pipelines, stainless steel and duplex stainless steel pipelines, etc., to achieve safe and precise welding processes and automated welding technology, which is convenient for large-scale promotion and application.

[0042] When the stud 11 is pressed against the two clamp seats 20 to close, the first pipe member inserted between the two flat bushings 30 is directly opposite to the second pipe member inserted between the two airway bushings 40. At this time, a pipe opening gap is formed between the first pipe member and the second pipe member, and Figure 2 A gas port 411 and a gas port span L2 are shown. In some embodiments, the pipe port gap formed by the first pipe fitting and the second pipe fitting is limited to be opposite to the gas port 411, so that the inert gas coming out of the gas port 411 is directly conducted to the pipe port gap between the first pipe fitting and the second pipe fitting, thereby improving the protective effect of the inert gas during welding.

[0043] In some embodiments, see Figure 2 Each flat bushing 30 is provided with at least two first protrusions 31, the first protrusions 31 are located on the inner side of the flat bushing 30, and the first protrusions 31 are distributed along the circumferential direction of the flat bushing 30; each airway bushing 40 is provided with at least two second protrusions 42, the second protrusions 42 are located on the inner side of the airway bushing 40, and the second protrusions 42 are distributed along the circumferential direction of the airway bushing 40. By setting the first protrusion 31 to directly contact the first pipe fitting and the second protrusion 42 to directly contact the second pipe fitting, the contact surface area between the flat bushing 30 and the first pipe fitting is reduced, and the contact surface area between the airway bushing 40 and the second pipe fitting is reduced, thereby reducing the influence of the manufacturing process on the positioning of the pipe fittings, and improving the positioning effect of the flat bushing 30 on the first pipe fitting and the airway bushing 40 on the second pipe fitting.

[0044] In some embodiments, see Figure 1 The axial end of the airway bushing 40 close to the flat bushing 30 is spaced apart from the clamp seat 20, and the airway 41 is smoothly formed to form the air port 411 formed on the inner side of the airway bushing 40. Figure 1 and Figure 2The air duct 41 is distributed along the annular direction of the air duct bushing 40, and sealing plates 43 are installed at both ends of the annular direction of the air duct 41. The sealing plates 43 are sealed and connected to the air duct bushing 40 and the support. A filter screen 412 is arranged in the air duct 41, and the filter screen 412 is spread between the air port 411 and the air inlet pipe 50. After the filter screen 412 is placed in the air duct 41, the air duct 41 is blocked by the sealing plate 43, leaving only the air port 411 as the outlet of the inert gas. By adding a filter screen 412 in the air duct 41, the filter screen 412 includes but is not limited to a copper wire filter screen 412, and the inert gas is filtered by the filter screen 412, the service life of the chuck is increased.

[0045] In some embodiments, see Figure 1 and Figure 2 The clamp seat 20 is an arc-shaped structure, which mainly refers to the outer peripheral side of the clamp seat 20 presenting an arc surface. Figure 1 The closing gap L1 of the clamp seat shown in the figure corresponds to that the central angle of the arc structure is less than and close to 180°.

[0046] In some embodiments, see Figure 1 The base member 10 is specifically designed as a C-shaped clamp, which includes a first arc segment 121, a straight segment 122 and a second arc segment 123. One end of the first arc segment 121 is connected to one end of the straight segment 122, and the other end of the straight segment 122 is connected to one end of the second arc segment 123. The two clamp seats 20 are respectively the first clamp seat 21 and the second clamp seat 22. The first clamp seat 21 is fitted and connected to the inner side of the first arc segment 121, and the first clamp seat 21 is connected to one end of the straight segment 122. The stud 11 is threadedly installed on the second arc segment 123, and the stud 11 is used to press the second clamp seat 22 to be joined with the first clamp seat 21. By designing the straight section 122 in the base member 10 , the second clamp seat 22 always rests on the straight section 122 during the process in which the stud 11 presses the second clamp seat 22 to close with the first clamp seat 21 , so that the second clamp seat 22 and the first clamp seat 21 can be accurately aligned.

[0047] It should be noted that, in the process of the stud 11 pressing the second clamp seat 22 to close with the first clamp seat 21, the first pipe fitting and the second pipe fitting located between the two clamp seats 20 also have a guiding effect on the closing process of the first clamp seat 21 and the second clamp seat 22, so that the first clamp seat 21 and the second clamp seat 22 can be accurately aligned.

[0048] In some embodiments, see Figure 1 and Figure 2 The second clamp seat 22 is connected to a top block 23 located on the outside, and the top block 23 is distributed along the axial direction of the second clamp seat 22. The top block 23 is used to contact the stud 11. The stud 11 presses the top block 23 so that the second clamp seat 22 can be tightly closed.

[0049] In some embodiments, the top block 23 is provided with an alignment hole, which is provided on a side of the top block 23 away from the second clamp seat 22, and the alignment hole is used for the stud 11 to pass through so as to align the axial ends of the two clamp seats 20 when the stud 11 is pressed against the two clamp seats 20 to close. When the stud 11 is pressed against the top block 23, the stud 11 is located in the alignment hole, and the axial ends of the two clamp seats 20 can be automatically aligned.

[0050] It should also be noted that in the solution where the alignment hole of the top block 23 is not provided, the axial ends of the two clamping seats 20 can also be aligned as much as possible through operation, and a slight misalignment of the axial ends of the two clamping seats 20 will not affect the smooth use of the chuck.

[0051] In some embodiments, the in-tube gas shielded welding chuck is also provided with a gas cylinder filled with inert gas, and the gas cylinder is connected to the air inlet pipe 50 through a hose, and the defect of gas leakage is improved by tightening the connection between the hose and the air inlet pipe 50.

[0052] The present application also provides a method for gas shielded welding of inner holes in pipes, which is based on the above-mentioned gas shielded welding chuck for inner holes in pipes to realize a welding process of single-sided welding and double-sided forming of inner hole welding of pipe mouth butt joints, including but not limited to the realization of helium-argon mixed gas shielded non-melting electrode arc welding for deep hole, full position, full blind and non-beveled inner hole welding of main heat exchangers.

[0053] First, fix the first pipe fitting on the head of the inner hole welding machine, adjust the axis of the first pipe fitting until the axis of the first pipe fitting is concentric with the gun head of the inner hole welding machine, adjust the verticality of the first pipe fitting and the rotating surface of the gun head of the inner hole welding machine, and adjust the extension length of the gun head of the inner hole welding machine so that the welding point is aligned with the seam position of the pipe mouth when the gun head rotates.

[0054] Next, a gas cylinder filled with inert gas prepared in advance is connected to the air inlet pipe 50 of the chuck through a hose, and the connection between the gas cylinder, the hose and the air inlet pipe 50 is tightened to prevent leakage of the inert gas.

[0055] Then, place the first pipe fitting together with the welding head close to the pipe end of the second pipe fitting to be connected, and adjust the up and down, left and right positions of the welding head to try to align the pipe ends of the two pipe fittings and make the two pipe fittings distributed on the same straight line.

[0056] The next step is to assemble the chuck. By adjusting the stud 11, the first clamp seat 21 and the second clamp seat 22 clamp and lock the two pipe fittings. At this time, the flat bushing 30 and the airway bushing 40 will be precisely matched to accurately adjust the pipe ends of the two pipe fittings to be concentric and keep the two pipe fittings distributed on the same straight line. At the same time, the misalignment of the pipe walls of the two pipe fittings is also adjusted to enable the two pipe ends to be accurately assembled to ensure accurate welding of the pipe openings.

[0057] Finally, when the internal gas passage 41 of the chuck is filled with inert gas and appropriate welding specifications are applied, the inner hole welding machine gun head rotates one circle inside the pipe mouth to complete the inner hole gas shielded welding of the pipe joint between the first pipe fitting and the second pipe fitting.

[0058] In the gas shielded welding method for inner holes in pipes of the present application, the upper and lower clamp seats 20 are fastened together by studs 11, and the flat bushings 30 and the airway bushings 40 are used to meet the assembly accuracy requirements of the pipe butt joint, thereby achieving high-precision and convenient assembly of the pipe butt joint, and providing full-range inert gas protection for the entire circumference of the pipe butt joint. This provides a powerful reference for the butt welding of new varieties and specifications of materials such as medium and small diameter safety-grade pipelines, copper alloy pipelines, stainless steel and duplex stainless steel pipelines, in achieving safe and precise welding processes and automated welding technologies, and is convenient for large-scale promotion and application.

[0059] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0060] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A gas shielded welding chuck for inner holes of pipes, characterized in that: include: A base member, threaded with studs; Two clamping seats are provided opposite to each other, one of which is fixedly connected to the base member, and the other clamping seat is used to abut against the stud; A flat bushing is provided with two lobes, and the two lobes of the flat bushing are respectively connected to the two clamping seats; An airway bushing is provided with two petals, the two petals of the airway bushing are connected to the two clamp seats respectively, the airway bushing is spaced apart from the flat bushing, and each petal of the airway bushing and the clamp seat enclose an airway, and the airway is connected to the inner side of the airway bushing; Inlet pipes, at least two of which are connected to the side of the clamp seat away from the airway bushing and communicated with the airway, and are used to input inert gas; Wherein, under the condition that the stud is pressed until the two clamp seats are closed, the first pipe member passing through the two halves of the flat bushing is directly opposite to the second pipe member passing through the two halves of the airway bushing.

2. The gas shielded welding chuck for inner hole of pipe according to claim 1, characterized in that: The air duct is connected to the inner side of the air duct bushing to form an air port. When the stud is pressed until the two clamp seats are closed, the first pipe fitting passed through the two halves of the flat bushing is directly opposite to the second pipe fitting passed through the two halves of the air duct bushing, and the pipe port gap formed by the first pipe fitting and the second pipe fitting is directly opposite to the air port.

3. The gas shielded welding chuck for inner hole of pipe as claimed in claim 2, characterized in that: Each petal of the flat bushing is provided with at least two first protrusions located on the inner side and distributed along the circumferential direction of the flat bushing, and each petal of the airway bushing is provided with at least two second protrusions located on the inner side and distributed along the circumferential direction of the airway bushing. When the stud is pressed until the two clamp seats are closed, the first protrusion contacts the first pipe fitting and the second protrusion contacts the second pipe fitting.

4. The gas shielded welding chuck for inner hole of pipe as claimed in claim 2, characterized in that: An axial end of the airway bushing close to the flat bushing is spaced apart from the clamping seat; The airway is distributed along the circumferential direction of the airway bushing, and sealing plates are installed at both ends of the airway in the circumferential direction, and the sealing plates are sealed and connected to the airway bushing and the support; A filter screen is arranged in the air passage, and the filter screen is spread between the air port and the air inlet pipe.

5. The gas shielded welding chuck for inner hole of pipe according to any one of claims 1 to 4, characterized in that: The clamping seat is an arc-shaped structure, and the central angle of the arc-shaped structure is less than 180°.

6. The gas shielded welding chuck for inner hole of pipe as claimed in claim 5, characterized in that: The base member is a C-shaped clamp, which includes a first arc segment, a straight segment, and a second arc segment, wherein an arcuate end of the first arc segment is connected to an end of the straight segment, and the other end of the straight segment is connected to an arcuate end of the second arc segment; The two clamp seats are respectively a first clamp seat and a second clamp seat, the first clamp seat is fitted and connected to the inner side of the first arc segment, and the first clamp seat is connected to one end of the straight segment, the stud is threadedly installed on the second arc segment, and the stud is used to press the second clamp seat to fit together with the first clamp seat.

7. The gas shielded welding chuck for inner hole of pipe according to claim 6, characterized in that: The second clamping seat is connected to a top block located on the outside, the top block is distributed along the axial direction of the second clamping seat, and the top block is used to contact the stud.

8. The gas shielded welding chuck for inner hole of pipe according to claim 7, characterized in that: The top block is provided with an alignment hole, which is opened on a side of the top block away from the second clamp seat. The alignment hole is used for the stud to pass through so as to align the axial ends of the two clamp seats when the stud is pressed until the two clamp seats are closed.

9. The gas shielded welding chuck for inner hole of pipe according to any one of claims 1 to 4, characterized in that: The gas shielded welding chuck for inner hole of pipe is also provided with a gas cylinder filled with inert gas, and the gas cylinder is connected with the air inlet pipe through a hose.

10. A method for gas shielded welding of a pipe inner hole, characterized in that: Using the gas shielded welding chuck for inner hole of pipe according to any one of claims 1 to 9, the method comprises: The first pipe fitting is fixedly mounted on the head of the inner hole welding machine; Place the first pipe installed on the machine head close to the second pipe to be butted and align the pipe ends; Put the two clamping seats on the first pipe fitting and the second pipe fitting and tighten the studs until the pipe openings are clamped; After the air passage is filled with inert gas, the gun head of the inner hole welding machine rotates around the first pipe for one circle to complete the welding of the butt joint between the first pipe and the second pipe.

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