No-gap narrow bevel external root welding method for long-distance pipelines

Abstract

This invention relates to the field of pipeline welding technology, specifically to a method for seamless narrow-groove external root welding of long-distance pipelines. It includes a narrow groove, comprising groove m and groove k, which are positioned opposite each other. After two pipeline sections are joined, groove m is located inside the pipeline, and groove k is located outside the pipeline, forming a blunt edge between groove m and groove k. The thickness of the blunt edge is f, where f ≤ 1 mm. The root of groove k is an arc-shaped fillet α, with a radius ≤ 2.4 mm. The angle between the sidewall of groove k and the outer generatrix of the pipeline is b, where b ≤ 95°. The width of groove m is 2e, where e ≤ 5 mm. The depth of groove m is g, where g ≤ 0.35 mm. The angle between the sidewall of groove m and the inner generatrix of the pipeline is c, where c ≤ 176°. After the two pipeline sections are joined to form groove m and groove k, the two pipeline sections are welded using a welding device. Compared with the gapped external root welding process, the present invention is easier to assemble in mountainous areas, has higher welding efficiency, and reduces construction costs.

Description

Technical Field

[0001] This invention relates to the field of pipeline welding technology, specifically to a method for gapless narrow bevel external root welding of long-distance pipelines. Background Technology

[0002] With the development of long-distance pipelines towards larger diameters and higher steel grades, automatic welding technology is increasingly used in pipeline construction to ensure the quality of on-site welds and improve welding efficiency. Automatic welding technology offers advantages such as stable welding processes, excellent weld mechanical properties, easy control of welding process parameters, and real-time data acquisition and transmission. It avoids the problem of welders privately adjusting welding parameters and violating process discipline during manual or semi-automatic welding operations, and has been widely applied in long-distance pipeline construction. For flat sections, the use of an internal welding machine for root welding combined with a dual-gun external welding machine for filling has achieved good results in long-distance pipeline construction. Especially for construction units, the diverse specifications of the pipelines they construct make it impossible to equip each type with a corresponding internal welding machine. This can easily lead to high overall equipment costs for construction units, low utilization of equipment resources, and a significant increase in construction costs.

[0003] For some special areas such as mountainous water networks, it is difficult to carry out the automated welding operation mode used in plains areas. Currently, automated pipeline welding construction in mountainous areas adopts a combined automated welding process, mainly using a combination of manual TIG / RMD / STT root welding and single-gun flux-cored wire upward welding. Additionally, a newer combined welding process has emerged, using automated TIG root welding and single-gun solid wire downward filling. However, the following problems exist:

[0004] Regarding manual argon arc welding for root pass and hot welding process: When using traditional tungsten inert gas (TIG) welding for root pass, the welding efficiency is low. In order to prevent automatic welding from burning through, argon arc welding is required for hot welding, which results in high labor intensity for welders.

[0005] Regarding the RMD / STT root welding process: The RMD / STT root welding process is greatly affected by environmental factors, especially in the humid environment of the south, where defects such as porosity and lack of fusion are prone to occur, resulting in a low first-pass yield of PAUT inspection.

[0006] Regarding the automated tungsten inert gas (TIG) root welding process: the efficiency improvement of automated TIG root welding compared to traditional manual TIG welding is not significant;

[0007] Regarding the single-gun flux-cored gas shielded upward welding filler and cover process: the bevel form is the traditional V-shaped bevel, and the gas shielded flux-cored welding wire filler process is used. The weld quality is not as stable as that of solid welding wire, and the welding filler amount is large, resulting in low welding efficiency.

[0008] Therefore, to address the aforementioned problems, it is necessary to develop a new and efficient welding process to replace the current mainstream combined automatic welding process, thereby improving welding quality and construction efficiency. Summary of the Invention

[0009] The technical problem to be solved by the present invention is a method for gapless narrow bevel external root welding of long-distance pipelines that can improve welding quality and construction efficiency.

[0010] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0011] A method for welding the outer root of a long-distance pipeline with a narrow bevel without gap, wherein the narrow bevel structure includes bevel m and bevel k, bevel m and bevel k are arranged opposite to each other, after the two pipeline sections are joined, bevel m is located on the inner side of the pipeline and bevel k is located on the outer side of the pipeline, and a blunt edge is formed between bevel m and bevel k.

[0012] The thickness of the blunt edge is f, where f ≤ 1 mm;

[0013] The root of the bevel k is an arc-shaped fillet a, and the radius of the arc-shaped fillet a is ≤2.4mm;

[0014] The angle between the side wall of the bevel k and the outer edge of the pipe is b, where b ≤ 95°;

[0015] The width of the bevel m is 2e, where e ≤ 5mm;

[0016] The depth of the bevel m is g, where g ≤ 0.35 mm;

[0017] The angle between the bevel m sidewall and the inner edge generatrix of the pipe is c, where c ≤ 176°;

[0018] After the two pipe sections are joined to form bevel m and bevel k, the two pipe sections are welded together using a welding device.

[0019] Specifically, the thickness of the blunt edge is f, which is 1 mm; the radius of the arc fillet a is 2.4 mm; the angle between the side wall of the bevel k and the outer generatrix of the pipe is b, which is 95°; the width of the bevel m is 2e, which is 10 mm; the depth of the bevel m is g, which is 0.35 mm; and the angle between the side wall of the bevel m and the inner generatrix of the pipe is c, which is 176°.

[0020] Specifically, the welding device includes an annular track fixed to the pipe, located on one side of the narrow bevel. An annular guide rail is concentrically fixed to the side of the annular track facing away from the narrow bevel. The guide rail is sleeved on the outside of the pipe, and a wavy guide groove is formed on its outer edge. A connecting seat is rotatably connected to the side of the annular track facing the narrow bevel. The connecting seat can rotate on the annular track according to the axis of the pipe. A support frame is fixed to the connecting seat, and a spherical hole is formed on the support frame. A spherical seat is installed in the spherical hole, and the spherical seat spherically mates with the spherical hole of the support frame. Multiple elastic components are evenly distributed around the outer circumference of the support frame, and the spherical seat and the support frame are connected by multiple elastic components. The components are connected, with the lower end of the spherical seat extending to the bottom of the support frame. A welding gun is threadedly connected to the lower end of the spherical seat, and a rotating ring is provided at the upper end of the spherical seat. Multiple sets of driving components are evenly distributed around the upper circumference of the rotating ring. The height of the multiple sets of driving components is different, and each set of driving components includes two vertical plates. The two plates are symmetrically arranged according to the axis of the rotating ring, and the included angle between the two plates of the same driving component is 180°. A connecting component is elastically slidably connected to the upper end of the connecting seat along the axial direction of the pipe. A guide rod is fixed at one end of the connecting component and inserted into the guide groove. A vertical rod is fixed at the other end of the connecting component, and a roller is rotatably connected to the lower end of the vertical rod. The axis of the roller is perpendicular to the axis of the pipe.

[0021] Specifically, the elastic component includes multiple lower connecting plates evenly distributed and fixed on the support frame, and an upper connecting plate corresponding to the lower connecting plates is fixed on the spherical seat. The upper connecting plate and the lower connecting plate are connected by a first spring.

[0022] Specifically, the upper outer edge of the spherical seat is machined with an annular groove, a connecting block is slidably engaged in the groove, the connecting block is fixedly connected to the rotating ring, and a positioning screw is threaded onto the connecting block, the positioning screw abutting tightly against the groove wall.

[0023] Specifically, the upper part of the upright plate facing the rotating ring is machined with an arc surface.

[0024] Specifically, the connecting assembly includes a push rod, a vertical rod, and a guide rod that are fixedly connected to the push rod. The push rod is slidably connected to the connecting seat. A slider is fixed on the vertical rod. The slider is slidably engaged in a groove on the connecting seat. The slider is connected to the groove wall of the groove by a second spring.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. Compared with the gapped external root welding process, this invention is easier to assemble in mountainous areas, has higher welding efficiency, reduces construction costs, can achieve precise droplet short-circuit transfer of solid welding wire for root welding, can effectively reduce the amount of weld metal filling, has a wide range of applications, and can be used in plains or special sections such as mountain water networks; and when used for continuous welding operations at line intersections in plains, only an internal aligner is used for assembly, eliminating the need for an internal welding machine, which can greatly reduce equipment investment and has a broad prospect for promotion and application.

[0027] 2. When the welding device of the present invention is used for welding, the swing amplitude of the welding gun can be adjusted according to the angle between the side wall of the bevel k and the outer edge generatrix of the pipe, so that the welding gun can be perpendicular to the side wall of the bevel k when it swings to the reversal point, thereby improving the quality of the bevel k welding and improving the practicality and applicability of the welding device.

[0028] 3. When the welding device of the present invention is used for welding, it can make the welding torch swing in an S-shape within the bevel K, simulating the manual welding method, which can improve the welding quality. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the narrow bevel of the present invention.

[0030] Figure 2 This is a schematic diagram of a welding device used to weld pipes.

[0031] Figure 3 This is a schematic diagram of the guide groove.

[0032] Figure 4 This is a schematic diagram showing the fit between the guide rod and the guide groove.

[0033] Figure 5 This is a schematic diagram showing the cooperation between the support frame and the connecting seat.

[0034] Figure 6 Schematic diagram of the fit between the support frame and the spherical seat

[0035] Figure 7 This is a schematic diagram of the interaction between the push rod and the vertical rod.

[0036] Figure 8 This is a schematic diagram of a rotating ring.

[0037] Figure 9 This is a sectional view of the support frame.

[0038] Figure 10 This is a cross-sectional view of the structure where the rotating ring and the spherical seat mate.

[0039] Figure 11 This is a schematic diagram showing the fit between the welding torch and the ball seat.

[0040] The names of the parts in the attached diagram are:

[0041] 1. Circular track; 2. Guide rail; 3. Guide groove; 4. Connecting seat; 5. Support frame; 6. Spherical hole; 7. Lower connecting plate; 8. Spherical seat; 9. Welding torch; 10. First spring; 11. Upper connecting plate; 12. Second spring; 13. Slot; 14. Rotating ring; 15. Connecting block; 16. Positioning screw; 17. Vertical plate; 18. Roller; 19. Push rod; 20. Slider; 21. Guide rod; 22. Vertical rod. Detailed Implementation

[0042] like Figure 1 As shown, a method for seamless narrow bevel external root welding of long-distance pipelines is described. The narrow bevel structure includes bevel m and bevel k, which are arranged opposite to each other. After the two pipeline sections are joined, bevel m is located on the inner side of the pipeline, and bevel k is located on the outer side of the pipeline. A blunt edge is formed between bevel m and bevel k.

[0043] The thickness of the blunt edge is f, where f ≤ 1 mm.

[0044] The root of the bevel k is an arc-shaped fillet a, and the radius of the arc-shaped fillet a is ≤2.4mm.

[0045] The angle between the bevel sidewall (k) and the outer edge of the pipe is b, where b ≤ 95°.

[0046] The width of the bevel m is 2e, where e ≤ 5mm.

[0047] The depth of the bevel m is g, where g ≤ 0.35 mm.

[0048] The angle between the bevel m sidewall and the inner edge generatrix of the pipe is c, where c ≤ 176°.

[0049] After the two pipe sections are joined to form bevel m and bevel k, the two pipe sections are welded together using a welding device.

[0050] The thickness of the blunt edge is f, which is 1 mm; the radius of the arc fillet a is 2.4 mm; the angle between the side wall of the bevel k and the outer generatrix of the pipe is b, which is 95°; the width of the bevel m is 2e, which is 10 mm; the depth of the bevel m is g, which is 0.35 mm; and the angle between the side wall of the bevel m and the inner generatrix of the pipe is c, which is 176°.

[0051] like Figure 2 and Figure 3 As shown, the welding device includes an annular track 1 fixed on the pipe. The annular track 1 is located on one side of the narrow bevel. An annular guide rail 2 is concentrically fixed on the side of the annular track 1 facing away from the narrow bevel. The guide rail 2 is sleeved on the outside of the pipe. A wavy guide groove 3 is opened on the outer edge of the guide rail 2. A connecting seat 4 is rotatably connected to the side of the annular track 1 facing the narrow bevel. The connecting seat 4 can make circular motion on the annular track 1 according to the axis of the pipe.

[0052] like Figures 4-11 As shown, a support frame 5 is fixed on the connecting seat 4, and a spherical hole 6 is formed on the support frame 5. A spherical seat 8 is installed in the spherical hole 6, and the spherical seat 8 spherically mates with the spherical hole 6 of the support frame 5. Multiple elastic components are evenly distributed around the outer circumference of the support frame 5. The spherical seat 8 and the support frame 5 are connected by multiple elastic components. The elastic components include multiple lower connecting plates 7 evenly distributed and fixed on the support frame 5, and an upper connecting plate 11 corresponding to the lower connecting plates 7 is fixed on the spherical seat 8. The upper connecting plate 11 and the lower connecting plate 7 are connected by a first spring 10.

[0053] The lower end of the spherical seat 8 extends below the support frame 5, and a welding gun 9 is threadedly connected to the lower end of the spherical seat 8.

[0054] A rotating ring 14 is provided at the upper end of the spherical seat 8. An annular groove 13 is machined on the upper outer edge of the spherical seat 8. A connecting block 15 is slidably engaged in the groove 13. The connecting block 15 is fixedly connected to the rotating ring 14. A positioning screw 16 is threaded onto the connecting block 15. The positioning screw 16 is tightly abutted against the groove wall of the groove 13.

[0055] Multiple sets of driving components are evenly distributed around the upper circumference of the rotating ring 14. The heights of the multiple sets of driving components are different. Each set of driving components includes two vertical plates 17. The two plates 17 are symmetrically arranged with respect to the axis of the rotating ring 14. The included angle between the two plates 17 of the same driving component is 180°. The upper part of the side of the plate 17 facing the rotating ring 14 is machined with an arc surface.

[0056] A connecting assembly is elastically slidably connected to the upper end of the connecting seat 4 along the axial direction of the pipe. A guide rod 21 is fixed to one end of the connecting assembly and is inserted into the guide groove 3. A vertical rod 22 is fixed to the other end of the connecting assembly. A roller 18 is rotatably connected to the lower end of the vertical rod 22, and the axis of the roller 18 is perpendicular to the axis of the pipe. The connecting assembly includes a push rod 19. The vertical rod 22 and the guide rod 21 are fixedly connected to the push rod 19. The push rod 19 is slidably connected to the connecting seat 4. A slider 20 is fixed on the vertical rod 22 and is slidably engaged in the groove on the connecting seat 4. The slider 20 is connected to the groove wall of the groove by a second spring 12.

[0057] When welding the pipe, the annular track 1 is fixed to the pipe, and the welding torch 9 is positioned in the middle of the bevel k. As the connecting seat 4 rotates around the pipe's axis on the annular track 1, the push rod 19, guided by the guide groove 3 on the guide rod 21, drives the vertical rod 22 and the roller 18 to reciprocate left and right in the axial direction of the pipe. During this reciprocating motion, the second spring 12 is intermittently compressed. The roller 18, through the vertical plates 17 on its left and right sides, allows the spherical seat 8 to swing left and right within the spherical hole 6 of the support frame 5, meaning the welding torch 9 can swing left and right within the bevel k. The first spring 10 ensures that the spherical seat 8, the rotating ring 14, and the welding torch 9 return to their initial positions after the roller 18 separates from the vertical plate 17. Therefore, during the process of the connecting seat 4 rotating around the axis of the pipe on the annular track 1, the motion trajectory of the welding torch 9 in the bevel k is the same as the motion trajectory of the guide rod 21 in the guide groove 3. That is, the welding torch 9 swings in an S-shape in the bevel k, simulating the manual welding method, which can improve the welding quality.

[0058] The rotating ring 14 can be rotated according to the angle b between the side wall of the bevel k and the outer edge generatrix of the pipe, thereby adjusting the height of the left and right vertical plates 17 of the roller 18. This changes the swing amplitude of the welding torch 9 within the bevel k, ensuring that the welding torch 9 is perpendicular to the side wall of the bevel k when it reaches the swing reversal point. Rotating the rotating ring 14 loosens the positioning screw 16, allowing the rotating ring 14 to rotate around the axis of the spherical seat 8, thus changing the height of the left and right vertical plates 17 of the roller 18. After adjusting the height of the left and right vertical plates 17, the positioning screw 16 can be rotated to fix the rotating ring 14 onto the spherical seat 8. By changing the height of the left and right vertical plates 17, the swing amplitude of the welding torch 9 within the bevel k can be altered. Simultaneously, rotating the welding torch 9 adjusts the distance between the welding torch 9 and the side wall of the bevel k, ensuring the quality of the pipe welding.

[0059] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of welding a gapless, narrow groove, outer root weld for long- distance pipelines, characterized in that, The narrow groove structure comprises a groove m and a groove k, the groove m and the groove k are oppositely arranged, the groove m is located inside the pipeline after the butt joint of the two pipeline sections, the groove k is located outside the pipeline, and a root face is formed between the groove m and the groove k; The thickness of the root face is f, and f≤1mm; The root of the groove k is an arc fillet a, and the radius of the arc fillet a is ≤2.4mm; The included angle between the side wall of the groove k and the generatrix of the outer edge of the pipeline is b, and b≤95°; The width of the groove m is 2e, and e≤5mm; The depth of the groove m is g, and g≤0.35mm; The included angle between the side wall of the groove m and the generatrix of the inner edge of the pipeline is c, and c≤176°; After the butt joint of the two pipeline sections forms the groove m and the groove k, the two pipeline sections are welded by using a welding device; The welding device comprises a ring track (1) fixed on the pipeline, the ring track (1) is located on the side of the narrow groove, a ring guide rail (2) is fixed concentrically on the side of the ring track (1) away from the narrow groove, the guide rail (2) is sleeved on the outside of the pipeline, a wave-shaped guide groove (3) is formed on the outer edge of the guide rail (2), a connecting seat (4) is rotationally connected to the side of the ring track (1) facing the narrow groove, the connecting seat (4) can make a circular motion on the ring track (1) according to the axis of the pipeline, a support frame (5) is fixed on the connecting seat (4), a spherical hole (6) is formed in the support frame (5), a spherical seat (8) is installed in the spherical hole (6), the spherical seat (8) is in spherical surface cooperation with the spherical hole (6) of the support frame (5), a plurality of elastic components are uniformly distributed on the outer side of the support frame (5), the spherical seat (8) and the support frame (5) are connected through the plurality of elastic components, the lower end of the spherical seat (8) extends below the support frame (5), a welding gun (9) is threadedly connected to the lower end of the spherical seat (8), a rotating ring (14) is arranged on the upper end of the spherical seat (8), a plurality of groups of driving members are uniformly distributed on the upper end of the rotating ring (14), the heights of the groups of driving members are different, each group of driving members comprises two vertical standing plates (17), the two standing plates (17) are symmetrically arranged according to the axis of the rotating ring (14), the included angle between the two standing plates (17) of the same driving member is 180°, a connecting assembly is elastically and slidably connected to the upper end of the connecting seat (4) in the axial direction of the pipeline, a guide rod (21) is fixed to one end of the connecting assembly, the guide rod (21) is inserted into the guide groove (3), a vertical rod (22) is fixed to the other end of the connecting assembly, a roller (18) is rotationally connected to the lower end of the vertical rod (22), and the axis of the roller (18) is perpendicular to the axis of the pipeline.

2. The method of gapless narrow groove external root welding of long pen pipelines according to claim 1, characterized in that, The thickness of the root face is f, and f≤1mm; the radius of the arc fillet a is 2.4mm; the included angle between the side wall of the groove k and the generatrix of the outer edge of the pipeline is b, and b≤95°; the width of the groove m is 2e, and e≤5mm; the depth of the groove m is g, and g≤0.35mm; and the included angle between the side wall of the groove m and the generatrix of the inner edge of the pipeline is c, and c≤176°.

3. The method of gapless narrow groove external root welding of long pen pipelines according to claim 1, characterized in that, The elastic component comprises a plurality of lower connecting plates (7) which are fixed on the support frame (5) in a circumferential direction, an upper connecting plate (11) corresponding to the lower connecting plate (7) is fixed on the spherical seat (8), and the upper connecting plate (11) and the lower connecting plate (7) are connected through a first spring (10).

4. The method of gapless narrow groove external root welding of long pen pipelines according to claim 1, characterized in that, An annular clamping groove (13) is formed on the upper outer edge of the spherical seat (8), a connecting block (15) is slidably clamped in the clamping groove (13), the connecting block (15) is fixedly connected with a rotating ring (14), a positioning screw (16) is threadedly connected on the connecting block (15), and the positioning screw (16) abuts against the groove wall of the clamping groove (13).

5. The method of gapless narrow groove external root welding of long pen pipelines according to claim 1, characterized in that, An arc surface is formed on the upper portion of the side of the vertical plate (17) facing the rotating ring (14).

6. The method of gapless narrow groove external root welding of long pen pipelines according to claim 1, characterized in that, The connecting assembly comprises a push rod (19), a vertical rod (22) and a guide rod (21), the vertical rod (22) and the guide rod (21) are fixedly connected with the push rod (19), the push rod (19) is slidably connected with the connecting seat (4), the vertical rod (22) is fixedly provided with a sliding block (20), the sliding block (20) is slidably clamped in a sliding groove on the connecting seat (4), and the sliding block (20) and the groove wall of the sliding groove are connected through a second spring (12).

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