Submerged arc welding device for small-caliber thick-wall pipe and its welding method

Abstract

The present application provides a submerged arc welding device for small-diameter thick-walled pipes and a welding method thereof, which relates to the technical field of submerged arc welding for small-diameter thick-walled pipes. A submerged arc welding device for small-diameter thick-walled pipes includes a base, on which two support mechanisms are slidably arranged. A welding mechanism is arranged between the two support mechanisms. An auxiliary mechanism is arranged on the welding head. The auxiliary mechanism includes a positioning component fixedly sleeved on the welding head and a winding component fixedly connected to the positioning component. The winding component is internally provided with a shielding piece. The positioning component is arranged in a U shape. The winding component can wind and unwind the shielding piece, and the shielding piece can be positioned at the bottom end of the U-shaped positioning component. The shielding piece can form a certain degree of surrounding state for the butt joint seam, so that during the welding process, the unmelted welding flux will not directly fall from the welding seam due to the rotation of the pipe, causing the metal molten pool to be exposed to the air and interfering with the formation of the weld seam.

Description

Technical Field

[0001] This application relates to the technical field of submerged arc welding for small-diameter thick-walled pipes. Specifically, it relates to a submerged arc welding device for small-diameter thick-walled pipes and its welding method. Background Art

[0002] Submerged arc welding is a welding method in which the arc burns under a layer of flux. Its inherent advantages such as stable welding quality, high welding productivity, no arc light, and very little fume make it the main welding method in the manufacture of important steel structures such as pressure vessels, pipe sections, and box-shaped beam columns.

[0003] When it comes to the welding work of small-diameter thick-walled pipe fittings, the existing conventional submerged arc welding method is to lay the flux on the workpiece, and the welding torch carries a continuously fed welding wire to generate an arc between the flux layer and the workpiece. The heat of the arc melts the welding wire, workpiece, and flux to form a molten metal pool, isolating them from the air. As the welding torch moves forward automatically, the arc continuously melts the workpiece metal, welding wire, and flux in front, while the edge of the molten pool at the back begins to cool and solidify to form a weld. Subsequently, the liquid slag also condenses to form a hard slag shell. After removing the slag shell and reprocessing the weld, the welding can be completed. During this process, since the flux needs to be laid on the workpiece, that is, the flux needs to face up and the welding torch needs to face down to form a flat welding posture to facilitate controlling the formation of the weld. However, for small-diameter thick-walled pipe fittings, due to their small diameter and short arc length under the same radian, during the welding process (with parameters unchanged), the residence time of the flux on the surface of the pipe fitting is much shorter than that of large-diameter pipe fittings (as the pipe fitting rotates, the flux gradually falls off the pipe fitting), which easily leads to a corresponding reduction in the input amount of the heat of the arc to the pipe fitting and the flux, thereby reducing the penetration depth of the weld and causing defects such as incomplete penetration. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems existing in the prior art. For this purpose, this application proposes a submerged arc welding device for small-diameter thick-walled pipes, comprising:

[0005] A base, on which two support mechanisms are slidably arranged. The support mechanisms are used to carry the pipe fitting and can drive the pipe fitting to rotate around the axial direction. A welding mechanism is arranged between the two support mechanisms. The welding mechanism is slidably installed on the base and can perform three-axis displacement on the base;

[0006] The welding mechanism comprises a support component, a wire feeding component, a flux funnel, and a welding head that are slidably matched with the base. The wire feeding component is used to continuously supply the welding wire to the welding head, and the flux funnel is used to continuously provide the flux to the welding area;

[0007] An auxiliary mechanism is provided on the welding head. The auxiliary mechanism includes a positioning component fixedly sleeved on the welding head, and a winding component fixedly connected to the positioning component. A shielding member is built in the winding component;

[0008] The positioning component is arranged in a U shape. The U-shaped positioning component can be telescopically changed both horizontally and vertically. The bottom end of the U-shaped positioning component and the welding head are respectively located on the upper and lower sides of the pipeline;

[0009] The winding component can wind and unwind the shielding member, and the shielding member can be positioned at the bottom end of the U-shaped positioning component.

[0010] Preferably, the support mechanism includes a first X-axis displacement member slidably matched with the base. A Z-axis displacement member is arranged on the displacement end of the first X-axis displacement member. A positioning frame is fixedly connected to the displacement end of the Z-axis displacement member. A clamping component and an active tensioning plate are symmetrically arranged on the positioning frame. A bidirectional telescopic member is arranged between the symmetrically arranged active tensioning plates. The bidirectional telescopic member is fixedly connected to the positioning frame, and the telescopic ends of the bidirectional telescopic member are respectively fixedly connected to the two active tensioning plates;

[0011] The clamping component and the active tensioning plate are connected by a connecting member, and the connecting member can rotate on the active tensioning plate. The active tensioning plate provides power for the radial change of the clamping component;

[0012] The clamping component is rotatably installed on the positioning frame. A motor is arranged on one side of the clamping component, and the motor is used to drive the clamping component to rotate.

[0013] Preferably, the support component includes a second X-axis displacement member slidably matched with the base. A Y-axis displacement member is fixedly connected to the displacement end of the second X-axis displacement member. A lifting member is fixedly connected to the displacement end of the Y-axis displacement member.

[0014] Preferably, the positioning component includes a fixed ring fixedly sleeved on the welding head. Fixed rods are symmetrically and damping slidably inserted on both sides of the fixed ring. The bottom ends of the fixed rods are sequentially and end-to-end fixedly connected with a first telescopic rod, a second telescopic rod and a third telescopic rod. The first telescopic rod, the second telescopic rod and the third telescopic rod form a U shape. Connecting rods are respectively fixedly connected between the symmetrically arranged first telescopic rod, second telescopic rod and third telescopic rod;

[0015] The end of the third telescopic rod is fixedly connected with a support.

[0016] Preferably, the winding component includes a winding cylinder with its open end facing downwards. A reel is rotatably arranged coaxially on the winding cylinder, and both ends of the reel penetrate through both ends of the winding cylinder. A clockwork spring is arranged on the reel, with one end of the clockwork spring fixedly connected to the reel and the other end fixedly connected to the winding cylinder. A bracket is fixedly connected to the winding cylinder, and the bracket is fixedly connected to the fixed ring.

[0017] Preferably, one end of the shielding member is fixedly connected to the reel. The shielding member extends out from the open end of the winding cylinder, and a clamping strip is fixedly connected to the end of the shielding member extending out of the winding cylinder. The clamping strip is in limit cooperation with the supporting member.

[0018] Preferably, abutting components are arranged at both ends of the winding cylinder. The abutting components include positioning segments symmetrically and fixedly connected to both ends of the winding cylinder, displacement segments slidably inserted into the positioning segments in a limited manner, and abutting rollers connected to the ends of the two displacement segments.

[0019] Preferably, a strip-shaped groove communicating with its internal cavity is arranged on the side wall of the positioning segment. One end of the displacement segment inserted into the positioning segment is provided with a threaded hole.

[0020] Preferably, the threaded hole on the displacement segment is fitted with a bolt. The threaded end of the bolt is connected to the displacement segment and is in sliding cooperation with the strip-shaped groove on the side wall of the positioning segment. The nut end of the bolt is clamped to the side wall of the positioning segment.

[0021] Preferably, convex strips are symmetrically and fixedly connected to the side wall of the shielding member. The convex strips are arranged in an array along the length direction of the shielding member, and the length direction of the convex strips is along the width direction of the shielding member.

[0022] Ventilation channels are arranged on the cylindrical wall of the winding cylinder.

[0023] Preferably, the protruding end of the convex strip is arranged in an arc shape.

[0024] Preferably, the symmetrically arranged convex strips are located at the edges of the shielding member.

[0025] Preferably, dissipation grooves are evenly arranged on the arc-shaped side wall of the winding cylinder.

[0026] Preferably, ventilation holes are symmetrically arranged on the end face of the winding cylinder, and the ventilation holes are distributed in multiple concentric rings.

[0027] Preferably, on the side of the shielding member provided with the convex strips, a special-shaped strip is also fixedly arranged. The special-shaped strip is arranged in an arc shape and is composed of a plurality of spaced special-shaped blocks. The special-shaped strips are symmetrically arranged on the shielding member, and the symmetrically arranged special-shaped strips are arranged in an array along the length direction of the shielding member.

[0028] Preferably, for the figure formed by the symmetrically arranged special-shaped strips, the opening at the top is larger than the opening at the bottom, and it gradually tapers from the top to the bottom.

[0029] Preferably, the height of the multiple special-shaped blocks in the special-shaped strip is not greater than the height of the convex strip.

[0030] An SAW device for small-diameter thick-wall pipes of the present application has the following beneficial effects:

[0031] 1. The shielding member can form a certain degree of surrounding state for the butt joint (welding joint), so that during the welding process, the unmelted flux will not directly fall from the welding joint due to the rotation of the pipe, causing the metal molten pool to be exposed to the air and interfering with the formation of the weld seam.

[0032] 2. The shielding member's delaying the shedding of the unmelted flux ensures to a certain extent the input of arc heat to the flux and the pipe fitting, avoiding the reduction of the penetration depth of the weld seam caused by insufficient heat and preventing the occurrence of welding failure of thick-wall pipe welding.

[0033] 3. By using the telescopic change of the structure of the positioning component itself, the positioning point of the shielding member at the bottom side of the pipe can be adjusted, changing the wrapping range and wrapping spacing of the shielding member for the welding joint to be applicable to the welding of pipes with different diameters.

[0034] On the other hand, the present application further provides a welding method for SAW of small-diameter thick-wall pipes, including the following steps:

[0035] S1: Positioning the pipes to be welded. The two pipes to be welded are butted through the two support mechanisms, so that the butt joint is located below the welding head.

[0036] S2: Positioning the auxiliary tooling. Through the displacement change of the welding mechanism, the welding head is displaced above the butt joint, and then through the length change of the local components in the positioning component, the end of the positioning component is located below the butt joint.

[0037] S3: Shielding arrangement. The shielding member is pulled out from the winding component, and the pulled-out end is positioned below the butt joint through the positioning component, so that the shielding member forms a semi-surrounding posture for the butt joint.

[0038] S4: Welding. The welding wire is continuously fed to the welding head through the wire feeding component, the flux funnel continuously feeds flux to the welding area to form a flux layer, the welding head causes an arc to be generated between the continuously fed welding wire and the weldment under the flux layer, the heat of the arc melts the welding wire, the pipe fitting and the flux to form a metal molten pool, and at the same time, the two pipes to be welded are driven by the support mechanism to rotate slowly synchronously and in the same direction, and the rotation direction is towards the shielding member.

[0039] S5: Weld formation. As the pipeline rotates, the metal molten pool gradually rotates towards the direction of the shielding member. During this process, the unmelted welding flux is blocked by the shielding member and will not immediately separate from the metal molten pool. Therefore, it continues to cover the metal molten pool until it falls off the pipeline after leaving the coverage range of the shielding member. During this process, the metal molten pool cools and forms.

[0040] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Brief Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 is a schematic diagram of the overall structure of a submerged arc welding device for small-diameter thick-walled pipes according to an embodiment of the present application;

[0043] Figure 2 is a schematic diagram of the structure of a support mechanism according to an embodiment of the present application;

[0044] Figure 3 is a schematic diagram of the structure of a welding mechanism according to an embodiment of the present application;

[0045] Figure 4 is a schematic diagram of the position and structure of an auxiliary mechanism according to an embodiment of the present application;

[0046] Figure 5 is a schematic diagram of the structure of an auxiliary mechanism according to an embodiment of the present application;

[0047] Figure 6 is an exploded view of the structure of an auxiliary mechanism according to an embodiment of the present application;

[0048] Figure 7 is a schematic diagram of the position and structure of an abutting assembly according to an embodiment of the present application;

[0049] Figure 8 is a schematic diagram of the position and structure of a rib according to an embodiment of the present application;

[0050] Figure 9 is a schematic diagram of the structure of a winding assembly according to an embodiment of the present application;

[0051] Figure 10It is a schematic diagram of the position of the special-shaped strip during the welding process according to an embodiment of the present application;

[0052] Figure 11 It is a schematic structural diagram of the special-shaped strip according to an embodiment of the present application.

[0053] Icons: 1. Base; 2. Support mechanism; 21. First X-axis displacement member; 22. Z-axis displacement member; 23. Positioning frame; 24. Clamping assembly; 25. Active tensioning plate; 26. Bidirectional telescopic member; 27. Motor; 3. Welding mechanism; 31. Support assembly; 311. Second X-axis displacement member; 312. Y-axis displacement member; 313. Lifting member; 32. Wire feeding assembly; 33. Flux funnel; 34. Welding head; 4. Auxiliary mechanism; 41. Positioning assembly; 411. Fixed ring; 412. Fixed rod; 413. First telescopic rod; 414. Second telescopic rod; 415. Third telescopic rod; 416. Link; 417. Support; 42. Rewinding assembly; 421. Rewinding cylinder; 422. Reel; 423. Hairspring; 424. Bracket; 425. Scattering groove; 426. Ventilation hole; 43. Shielding member; 431. Card strip; 432. Ridge; 44. Abutting assembly; 441. Positioning section; 442. Displacement section; 443. Abutting roller; 444. Bolt; 45. Special-shaped strip. Detailed implementation manners

[0054] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0055] As Figures 1 - 11 shown, a submerged arc welding device for small-diameter thick-walled pipes according to an embodiment of the present application includes a base 1. Two support mechanisms 2 are slidably arranged on the base 1. The support mechanisms 2 are used to carry the pipe fittings and can drive the pipe fittings to rotate around the axial direction. A welding mechanism 3 is arranged between the two support mechanisms 2. The welding mechanism 3 is slidably installed on the base 1, and the welding mechanism 3 can perform three-axis displacement on the base 1 to facilitate the welding operation of the pipeline.

[0056] The welding mechanism 3 includes a support assembly 31 slidably engaged with the base 1, a wire feeding assembly 32, a flux hopper 33, and a welding head 34. The wire feeding assembly 32 is used to continuously feed the welding wire to the welding head 34, and the flux hopper 33 is used to continuously supply the flux to the welding area. It should be noted that in the embodiments of the present application, the wire feeding assembly 32, the flux hopper 33, and the welding head 34 are prior arts. Specifically, how to continuously feed the welding wire and the flux are prior arts and will not be elaborated in the embodiments of the present application.

[0057] Among them, an auxiliary mechanism 4 is provided on the welding head 34. The auxiliary mechanism 4 includes a positioning assembly 41 fixedly sleeved on the welding head 34, and a winding assembly 42 fixedly connected to the positioning assembly 41. The winding assembly 42 internally contains a shielding member 43.

[0058] The positioning assembly 41 is arranged in a U shape. The U-shaped positioning assembly 41 can be telescopically changed both horizontally and vertically. The bottom end of the U-shaped positioning assembly 41 and the welding head 34 are respectively located on the upper and lower sides of the pipeline. The telescopically changeable U-shaped positioning assembly 41 can change its positioning points according to the actual size of the pipeline, that is, the specific position of the bottom end of the positioning assembly 41 on the bottom side of the pipeline, so as to be applicable to pipelines of different sizes.

[0059] The winding assembly 42 can wind and unwind the shielding member 43, and the shielding member 43 can be positioned at the bottom end of the U-shaped positioning assembly 41.

[0060] In addition, the submerged arc welding device for small-diameter thick-walled pipes according to the embodiments of the present application further has the following additional technical features:

[0061] As Figure 2 shown, the support mechanism 2 includes a first X-axis displacement member 21 slidably engaged with the base 1. A Z-axis displacement member 22 is provided on the displacement end of the first X-axis displacement member 21. It can be understood that the first X-axis displacement member 21 and the Z-axis displacement member 22 can realize the horizontal and vertical displacements of the pipeline relative to the base 1. A positioning frame 23 is fixedly connected to the displacement end of the Z-axis displacement member 22. Clamping assemblies 24 and active tensioning plates 25 are symmetrically arranged on the positioning frame 23. A two-way telescopic member 26 is arranged between the symmetrically arranged active tensioning plates 25. The two-way telescopic member 26 is fixedly connected to the positioning frame 23, and the telescopic ends of the two-way telescopic member 26 are respectively fixedly connected to the two active tensioning plates 25.

[0062] The clamping assembly 24 and the active tensioning plate 25 are connected by a connecting piece, which is rotatable on the active tensioning plate 25. The active tensioning plate 25 provides power for radial change of the clamping assembly 24. It should be noted that in the embodiment of the present application, the clamping assembly 24 is provided with a radial expansion and contraction mechanism. Driven by the expansion and contraction change of the active tensioning plate 25 under the two-way telescopic member 26, a displacement along the axial direction of the pipeline occurs, causing the radial expansion and contraction mechanism on the clamping assembly 24 to expand and contract, so as to complete the clamping of the pipeline. The design that the connecting piece is rotatable on the active tensioning plate 25 enables the active tensioning plate 25 not to be interfered when the clamping assembly 24 rotates synchronously with the pipeline.

[0063] The clamping assembly 24 is rotatably installed on the positioning frame 23. A motor 27 is arranged on one side of the clamping assembly 24, and the motor 27 is used to drive the clamping assembly 24 to rotate. Specifically, a gear ring can be arranged on the side wall of the clamping assembly 24, and a gear is arranged on the output shaft of the motor 27, and the gear and the gear ring are meshed. In this way, the clamping assembly 24 can be driven to rotate by the motor 27. It should be noted that the rotating shaft is coaxial with the pipeline.

[0064] The specific structures of the above-mentioned clamping assembly 24 and the active tensioning plate 25 are prior arts and will not be elaborated in the embodiment of the present application. It is only for the function of completing the clamping of the pipeline and enabling the pipeline to rotate during the clamping process.

[0065] Furthermore, the support assembly 31 includes a second X-axis displacement member 311 that is slidably matched with the base 1. A Y-axis displacement member 312 is fixedly connected to the displacement end of the second X-axis displacement member 311, and a lifting member 313 is fixedly connected to the displacement end of the Y-axis displacement member 312.

[0066] It can be understood that through the second X-axis displacement member 311, the Y-axis displacement member 312 and the lifting member 313, the welding head 34 can be displaced in three axes relative to the base 1, so as to better correct the specific position of the docking seam between the welding head 34 and the pipeline.

[0067] It should be noted that the first X-axis displacement member 21, the Z-axis displacement member 22, the second X-axis displacement member 311 and the Y-axis displacement member 312 in the embodiment of the present application can be devices with linear displacement functions such as electric sliding tables in the prior art; the two-way telescopic member 26 and the lifting member 313 can be devices with linear expansion and contraction functions such as hydraulic cylinders (double-headed hydraulic cylinders) in the prior art.

[0068] Such as Figures 4 - 6As shown, the positioning component 41 includes a fixing ring 411 fixedly sleeved on the welding head 34. Fixed rods 412 are symmetrically and damping-slidingly inserted on both sides of the fixing ring 411 (it should be noted that the design of damping-sliding insertion enables the position of the fixed rod 412 to be actually adjusted on the fixing ring 411, that is, the height of the bottom end of the fixed rod 412 is adjustable). At the bottom ends of the fixed rods 412, a first telescopic rod 413, a second telescopic rod 414, and a third telescopic rod 415 are fixedly connected end to end in sequence. The first telescopic rod 413, the second telescopic rod 414, and the third telescopic rod 415 form a U-shaped structure. Connecting rods 416 are fixedly connected between the symmetrically arranged first telescopic rod 413, second telescopic rod 414, and third telescopic rod 415 respectively. It can be understood that by the respective telescopic changes of the first telescopic rod 413, the second telescopic rod 414, and the third telescopic rod 415, the coverage range of the U-shaped structure can be changed, that is, the specific position of the end of the third telescopic rod 415 can be changed. At the same time, the design of the connecting rod 416 enhances the stability between the symmetrically arranged first telescopic rod 413, second telescopic rod 414, and third telescopic rod 415.

[0069] It should be noted that the first telescopic rod 413, the second telescopic rod 414, and the third telescopic rod 415 can be prior arts with linear telescopic functions and locking functions. In the embodiments of the present application, it is not limited to the design of the U-shaped structure. In actual operation, prior arts such as a manipulator can be preferably used as long as the functions of applying to pipes with different diameters and end positioning can be realized.

[0070] A support 417 is fixedly connected to the end of the third telescopic rod 415. It should be noted that, as Figure 6 shown, the upper end of the support 417 is U-shaped to facilitate the positioning of the shielding member 43.

[0071] Furthermore, as Figure 6 and Figure 7 shown, the winding component 42 includes a winding drum 421. The open end of the winding drum 421 faces downward. A reel 422 is coaxially rotatably arranged on the winding drum 421. Both ends of the reel 422 penetrate through both ends of the winding drum 421. A spiral spring 423 is arranged on the reel 422 (preferably, the spiral spring 423 can be symmetrically arranged at both ends of the reel 422 extending out of the winding drum 421). One end of the spiral spring 423 is fixedly connected to the reel 422, and the other end of the spiral spring 423 is fixedly connected to the winding drum 421. A bracket 424 is fixedly connected to the winding drum 421, and the bracket 424 is fixedly connected to the fixing ring 411.

[0072] One end of the shielding member 43 is fixedly connected to the reel 422. The shielding member 43 extends out from the open end of the winding drum 421, and a clamping strip 431 is fixedly connected to the end of the shielding member 43 extending out of the winding drum 421. The clamping strip 431 and the support 417 are in limit cooperation (specifically, the clamping strip 431 is clamped in the U-shaped part at the top end of the support 417).

[0073] Among them, abutting components 44 are arranged at both ends of the winding drum 421. The abutting components 44 include positioning segments 441 symmetrically fixed to both ends of the winding drum 421, displacement segments 442 that are limited and slidably inserted into the positioning segments 441, and abutting rollers 443 connected to the ends of the two displacement segments 442.

[0074] Furthermore, strip-shaped grooves communicating with the internal cavity of the positioning segment 441 itself are arranged on the side wall of the positioning segment 441, and threaded holes are arranged at one end of the displacement segment 442 inserted into the positioning segment 441.

[0075] Among them, the threaded holes on the displacement segment 442 are adapted to bolts 444. The threaded ends of the bolts 444 are connected to the displacement segment 442 and are slidably matched with the strip-shaped grooves on the side wall of the positioning segment 441. The nut ends of the bolts 444 are clamped to the side wall of the positioning segment 441.

[0076] It can be understood that by loosening and tightening the bolts 444 on the displacement segment 442, the displacement segment 442 can change its position within the positioning segment 441 and be positioned. Subsequently, the abutting action of the abutting roller 443 on the shielding member 43 is realized, so that the distance between the shielding member 43 and the side wall of the pipeline is adjustable.

[0077] It should be noted that in the embodiment of the present application, the shielding member 43 can be made of a metal material that is heat-resistant and has a certain flexibility, including but not limited to steel sheets.

[0078] Next, the use process of a submerged arc welding device for small-diameter thick-walled pipes according to an embodiment of the present application will be described with reference to the accompanying drawings:

[0079] During use, the two pipes to be welded are coaxially butted through the two supporting mechanisms 2, so that the butting seam is located below the welding head 34. Through the displacement change of the supporting assembly 31, the distance and position between the welding head 34 and the butting seam are corrected. After the position of the welding head 34 is positioned, through the respective telescopic changes of the first telescopic rod 413, the second telescopic rod 414 and the third telescopic rod 415 arranged in a C shape, the position of the support 417 is positioned at the bottom side of the pipe. Then, the shielding member 43 is pulled out from the winding drum 421, and the clamping strip 431 is clamped to the U-shaped part at the top of the support 417 for positioning. Through the length change of the displacement section 442 on the positioning section 441, the abutting roller 443 abuts against the shielding member 43 from the outlet end of the winding drum 421, and the shielding member 43 is close to the pipe side wall under the action of the abutting roller 443. In this way, at this time, the shielding member 43 forms a posture of partially wrapping the pipe (butting seam). During the welding process of the pipe, the clamping assembly 24 and the pipe thereon are driven by the motor 27 to rotate synchronously in the same direction. As is well known, during the submerged arc welding process, the flux needs to be continuously supplied and evenly laid on the butting seam to form a flux layer. The welding head 34 causes the continuously fed welding wire to generate an arc between the flux layer and the workpiece (pipe). The heat of the arc melts the welding wire, pipe fitting and flux to form a molten metal pool. After the molten metal pool cools, the weld is formed. In the embodiment of the present application, the pipe rotates towards the shielding member 43 direction (see Figure 4 , that is Figure 4 shown, the small-diameter thick-walled pipe rotates clockwise). In this way, the formed molten metal pool and the unmelted flux covering it will follow the rotation displacement of the pipe towards the shielding member 43. Under the blocking action of the shielding member 43, the unmelted flux that should have directly fallen at this time will not immediately separate from the molten metal pool. Therefore, it will continue to cover the molten metal pool, avoiding defects in the weld formation due to the direct shedding of the flux from the molten metal pool and exposure to the air. As the pipe rotates, the unmelted flux will not fall off until it has separated from the coverage of the shielding member 43. The delay in the shedding of the unmelted flux by the shielding member 43 ensures to a certain extent the input of the arc heat to the flux and the pipe fitting, avoiding the reduction of the penetration depth of the weld due to insufficient heat, and then preventing the occurrence of welding failure of the thick-walled pipe.

[0080] In the related art, when performing submerged arc welding on a small-diameter thick-walled pipe, in order to prevent the welding flux from falling off the molten metal pool formed during the welding process prematurely, a shielding member 43 is used to wrap and cover the molten metal pool after welding to a certain extent, so as to delay the coverage of the unmelted welding flux on the molten metal pool. However, for the formation of the weld seam, the molten metal pool needs to be cooled in time. The coverage of the molten metal pool by the shielding member 43 will reduce the cooling rate of the molten metal pool and prolong the forming time of the weld seam. Moreover, since the heat within the coverage range is not dissipated enough, it will be transferred to the un-welded part, causing the pipe fittings at the un-welded part (in front of the molten pool) to be preheated, resulting in adverse phenomena such as the widening of the weld seam and the shallowing of the penetration depth.

[0081] According to some embodiments of the present application, as Figure 8 and Figure 9 shown, convex strips 432 are symmetrically and fixedly connected to the side wall of the shielding member 43. The convex strips 432 are arranged in an array along the length direction of the shielding member 43, and the length direction of the convex strips 432 is arranged along the width direction of the shielding member 43. It should be noted that in the embodiments of the present application, the convex strips 432 are arranged on the side of the shielding member 43 facing the pipe.

[0082] It can be understood that the setting of the convex strips 432 can leave at least a space equal to the height of the convex strips 432 between the shielding member 43 and the side wall of the pipe, so as to leave a ventilation space between the shielding member 43 and the side wall of the pipe, which is helpful for heat dissipation. And the length direction of the convex strips 432 is arranged along the width direction of the shielding member 43, which can further increase the ventilation area between the shielding member 43 and the side wall of the pipe, and at the same time will not affect the winding of the shielding member 43 in the winding drum 421.

[0083] Ventilation channels are provided on the barrel wall of the winding drum 421.

[0084] Furthermore, the protruding end of the convex strip 432 is arranged in an arc shape, which reduces the contact area between the convex strip 432 and the side wall of the pipe, and is also beneficial to reducing the friction force between the convex strip 432 and the side wall of the pipe.

[0085] Among them, the symmetrically arranged convex strips 432 are located at the edge of the shielding member 43, as far as possible from the butt joint between the two pipes, so as to avoid scraping the unmelted welding flux during the welding process.

[0086] Furthermore, dissipation grooves 425 are uniformly arranged on the arc-shaped side wall of the winding drum 421.

[0087] Furthermore, ventilation holes 426 are symmetrically arranged on the end face of the winding drum 421. The ventilation holes 426 are distributed in multiple concentric rings, enhancing the ventilation and heat dissipation effect inside the winding drum 421.

[0088] Thus, during use, the shielding member 43 is positioned on the support 417 through the clamping strip 431. At this time, the shielding member 43 abuts against the side wall of the pipeline through the convex strip 432 thereon, and the shielding member 43 forms a wrapped posture with a spacing around the pipeline. In this way, during the welding process, the shielding member 43 can still normally delay the shedding of the unmelted flux, and at the same time, due to the existence of the convex strip 432, a ventilation spacing is formed between the shielding member 43 and the side wall of the pipeline, which can enhance the dissipation of heat in the metal molten pool, reduce the preheating effect on the pipe fittings at the un-welded part (in front of the molten pool), and ensure the welding quality to a certain extent. At the same time, due to the dissipation grooves 425 and ventilation holes 426 respectively provided on the arc-shaped side wall and the end face of the winding drum 421, after the welding is completed, the shielding member 43 can continue to dissipate heat after being wound into the winding drum 421. At the same time, due to the existence of the convex strip 432, a spacing can be left between the layers of the shielding member 43 in the wound state, further improving the heat dissipation effect.

[0089] In the related art, during the welding process, the pipeline needs to rotate continuously. Therefore, there will be friction between the unmelted flux covering the metal molten pool and the shielding member 43, and this friction will cause the unmelted flux to displace on the metal molten pool, unable to ensure the coverage of the metal molten pool by the unmelted flux. Once the metal molten pool has not completely cooled and formed, and the unmelted flux falls off from the metal molten pool due to the friction with the shielding member 43, resulting in the exposure of the metal molten pool to the air, which will cause defects in the weld seam.

[0090] According to some embodiments of the present application, as Figure 10 and Figure 11 shown, on the side of the shielding member 43 provided with the convex strip 432, a special-shaped strip 45 is also fixedly provided. The special-shaped strip 45 is arranged in an arc shape. The special-shaped strip 45 is composed of a plurality of special-shaped blocks arranged at intervals. The special-shaped strip 45 is symmetrically arranged on the shielding member 43, and the symmetrically arranged special-shaped strips 45 are arranged in an array along the length direction of the shielding member 43.

[0091] As Figure 11 shown, for the figure surrounded by the symmetrically arranged special-shaped strips 45, the opening at the top is larger than the opening at the bottom, and it gradually converges from the top to the bottom.

[0092] It should be noted that the symmetrically arranged special-shaped strips 45 are respectively located on both sides of the butt joint of the two pipelines.

[0093] Among them, for the plurality of special-shaped blocks in the special-shaped strip 45, their height is not greater than the height of the convex strip 432.

[0094] It should be noted that preferably, in the embodiments of the present application, the amplitude of all the special-shaped blocks constituting the special-shaped strip 45 along the length direction of the shielding member 43 should not be greater than the amplitude of the convex strip 432 to avoid interfering with the winding action of the shielding member 43.

[0095] Thus, in the embodiments of the present application, during specific use, after the pipeline carrying the metal molten pool and the unmelted flux covering it rotates into the coverage range of the shielding member 43, as Figure 10 and Figure 11 shown, the unmelted flux displaces downward along with the pipeline towards the lower part of the shielding member 43 (one end of the clamping strip 431). During this process, since the shielding member 43 remains stationary, and the special-shaped strips 45 symmetrically arranged thereon form an obstacle with the top opening larger than the bottom opening, the unmelted flux will be blocked by the special-shaped strips 45 symmetrically arranged on both sides of the butt joint. As the pipeline rotates, the unmelted flux will form a gathering movement gradually approaching the butt joint. In this way, to a certain extent, the special-shaped strips 45 prevent the unmelted flux from displacing on the metal molten pool due to friction with the shielding member 43 during the rotation process, resulting in the phenomenon that the coverage of the metal molten pool by the unmelted flux cannot be guaranteed. At the same time, since the special-shaped strip 45 is composed of multiple special-shaped blocks arranged at intervals, it ensures that it will not affect the normal winding of the shielding member 43. At the same time, the interval between the special-shaped blocks also fully guarantees the ventilation channel between the shielding member 43 and the side wall of the pipeline, avoiding affecting the heat dissipation effect within the coverage range of the shielding member 43.

[0096] On the other hand, the embodiments of the present application further provide a submerged arc welding method for small-diameter thick-walled pipes, including the following steps:

[0097] S1: Positioning the pipeline to be welded. Two pipelines to be welded are butt-jointed through two support mechanisms 2, so that the butt joint is located below the welding head 34;

[0098] S2: Positioning the auxiliary tooling. Through the displacement change of the welding mechanism 3, the welding head 34 is displaced above the butt joint, and then through the length change of local components within the positioning assembly 41, the end of the positioning assembly 41 is located below the butt joint;

[0099] S3: Shielding arrangement. The shielding member 43 is pulled out from the winding assembly 42, and the pulled-out end is positioned below the butt joint through the positioning assembly 41, so that the shielding member 43 forms a semi-surrounding posture for the butt joint;

[0100] S4: Welding. The welding wire is continuously fed to the welding head 34 through the wire feeding assembly 32, and the flux funnel 33 continuously feeds the flux to the welding area to form a flux layer. The welding head 34 causes an arc to be generated between the continuously fed welding wire and the welded part under the flux layer. The heat of the arc melts the welding wire, the pipe fitting, and the flux to form a metal molten pool. At the same time, the two pipelines to be welded are driven by the support mechanism 2 to rotate synchronously and slowly in the same direction, and the rotation direction is towards the shielding member 43;

[0101] S5: Weld formation. As the pipe rotates, the metal molten pool gradually rotates towards the shielding member 43. During this process, the unmelted flux is blocked by the shielding member 43 and does not immediately break away from the metal molten pool. Therefore, it continues to cover the metal molten pool until it falls off the pipe after leaving the coverage range of the shielding member 43. During this process, the metal molten pool cools and forms.

[0102] It should be noted that the specific model specifications of the first X-axis displacement member 21, Z-axis displacement member 22, clamping assembly 24, bi-directional telescopic member 26, motor 27, second X-axis displacement member 311, Y-axis displacement member 312, lifting member 313, wire feeding assembly 32, flux hopper 33, welding head 34, hairspring 423 and bolt 444 need to be selected according to the actual specifications of the device, etc. The specific selection calculation method adopts the existing technology in this field, so it will not be elaborated in detail.

[0103] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automatic submerged arc welding device for small-diameter thick-wall pipes, characterized in that, Comprising: A base (1), on which two support mechanisms (2) are slidably arranged. The support mechanisms (2) are used to carry pipe fittings and can drive the pipe fittings to rotate around the axial direction. A welding mechanism (3) is arranged between the two support mechanisms (2). The welding mechanism (3) is slidably installed on the base (1), and the welding mechanism (3) can perform three-axis displacement on the base (1); The welding mechanism (3) comprises a support component (31), a wire feeding component (32), a flux funnel (33) and a welding head (34) that are slidably matched with the base (1). The wire feeding component (32) is used to continuously feed welding wire to the welding head (34), and the flux funnel (33) is used to continuously supply flux to the welding area; An auxiliary mechanism (4) is arranged on the welding head (34). The auxiliary mechanism (4) comprises a positioning component (41) fixedly sleeved on the welding head (34), and a winding component (42) fixedly connected to the positioning component (41). The winding component (42) is internally provided with a shielding member (43); The positioning component (41) is arranged in a U shape. The U-shaped positioning component (41) can be telescopically changed in both its horizontal and vertical directions. The bottom end of the U-shaped positioning component (41) and the welding head (34) are respectively located on the upper and lower sides of the pipeline; The winding component (42) can wind and unwind the shielding member (43), and the shielding member (43) can be positioned at the bottom end of the U-shaped positioning component (41); The positioning component (41) comprises a fixing ring (411) fixedly sleeved on the welding head (34). Fixed rods (412) are symmetrically and damping slidably inserted on both sides of the fixing ring (411). The bottom ends of the fixed rods (412) are sequentially and fixedly connected end to end with a first telescopic rod (413), a second telescopic rod (414) and a third telescopic rod (415). The first telescopic rod (413), the second telescopic rod (414) and the third telescopic rod (415) form a U shape. Link rods (416) are fixedly connected between the symmetrically arranged first telescopic rod (413), second telescopic rod (414) and third telescopic rod (415); The end of the third telescopic rod (415) is fixedly connected with a support (417); The winding component (42) comprises a winding drum (421). The opening end of the winding drum (421) faces downward. A winding shaft (422) is coaxially rotatably arranged on the winding drum (421). The two ends of the winding shaft (422) penetrate through the two ends of the winding drum (421). A clockwork spring (423) is arranged on the winding shaft (422). One end of the clockwork spring (423) is fixedly connected to the winding shaft (422), and the other end of the clockwork spring (423) is fixedly connected to the winding drum (421). A support (424) is fixedly connected to the winding drum (421), and the support (424) is fixedly connected to the fixing ring (411); On the side walls of the shielding member (43), convex strips (432) are symmetrically fixed. The convex strips (432) are arranged in an array along the length direction of the shielding member (43), and the length direction of the convex strips (432) is arranged along the width direction of the shielding member (43); on the cylindrical wall of the winding drum (421), a ventilation channel is provided; the protruding end of the convex strip (432) is arranged in an arc shape; the symmetrically arranged convex strips (432) are located at the edge of the shielding member (43); on the arc-shaped side wall of the winding drum (421), dissipation grooves (425) are evenly arranged; on the end face of the winding drum (421), ventilation holes (426) are symmetrically arranged, and the ventilation holes (426) are distributed in a plurality of concentric rings.

2. The submerged arc welding device for a small-caliber thick-walled pipe according to claim 1, characterized in that: The support mechanism (2) includes a first X-axis displacement member (21) that is slidably matched with the base (1). On the displacement end of the first X-axis displacement member (21), a Z-axis displacement member (22) is provided. On the displacement end of the Z-axis displacement member (22), a positioning frame (23) is fixed. On the positioning frame (23), a clamping assembly (24) and an active tensioning plate (25) are symmetrically arranged. Between the symmetrically arranged active tensioning plates (25), a bidirectional telescopic member (26) is provided. The bidirectional telescopic member (26) is fixed to the positioning frame (23), and the telescopic ends of the bidirectional telescopic member (26) are respectively fixed to the two active tensioning plates (25); The clamping assembly (24) and the active tensioning plate (25) are connected by a connecting member, and the connecting member is rotatable on the active tensioning plate (25). The active tensioning plate (25) provides power for radial change of the clamping assembly (24); The clamping assembly (24) is rotatably installed on the positioning frame (23). On one side of the clamping assembly (24), a motor (27) is provided, and the motor (27) is used to drive the clamping assembly (24) to rotate.

3. The submerged arc welding device for small-caliber thick-wall pipes according to claim 1, characterized in that: The support assembly (31) includes a second X-axis displacement member (311) that is slidably matched with the base (1). On the displacement end of the second X-axis displacement member (311), a Y-axis displacement member (312) is fixed. On the displacement end of the Y-axis displacement member (312), a lifting member (313) is fixed.

4. The submerged arc welding device for small-caliber thick-walled pipes according to claim 1, characterized in that: One end of the shielding member (43) is fixed to the winding shaft (422). The shielding member (43) extends out from the open end of the winding drum (421), and a clamping strip (431) is fixed to the end of the shielding member (43) that extends out of the winding drum (421). The clamping strip (431) is in limit fit with the support (417).

5. The submerged arc welding device for small-caliber thick-walled pipes according to claim 1, characterized in that: At both ends of the winding drum (421), an abutting assembly (44) is provided. The abutting assembly (44) includes positioning segments (441) symmetrically fixed to both ends of the winding drum (421), displacement segments (442) that are limited and slidably inserted into the positioning segments (441), and abutting rollers (443) connected to the ends of the two displacement segments (442).

6. The submerged arc welding device for small-caliber thick-walled pipes according to claim 5, characterized in that: A strip-shaped groove communicating with its internal cavity is provided on the side wall of the positioning section (441), and a threaded hole is provided at one end of the displacement section (442) inserted into the positioning section (441).

7. The submerged arc welding device for small-diameter thick-walled pipes according to claim 6, characterized in that: The threaded hole on the displacement section (442) is fitted with a bolt (444). The threaded end of the bolt (444) is connected to the displacement section (442) and is in sliding fit with the strip-shaped groove on the side wall of the positioning section (441). The nut end of the bolt (444) is clamped to the side wall of the positioning section (441).

8. A submerged arc welding method for small-diameter thick-walled pipes, characterized in that, Using a submerged arc welding device for small-diameter thick-walled pipes according to any one of claims 1-7 comprising the following steps: S1: Positioning the pipes to be welded. The two pipes to be welded are butted through the two support mechanisms (2) so that the butting seam is located below the welding head (34). S2: Positioning the auxiliary tooling. Through the displacement change of the welding mechanism (3), the welding head (34) is displaced above the butting seam, and then through the length change of local components in the positioning assembly (41), the end of the positioning assembly (41) is located below the butting seam. S3: Shielding arrangement. The shielding member (43) is pulled out from the winding assembly (42), and the pulled-out end is positioned below the butting seam through the positioning assembly (41) so that the shielding member (43) forms a semi-surrounding posture for the butting seam. S4: Welding. The wire feeding assembly (32) continuously feeds the welding wire to the welding head (34), the flux hopper (33) continuously feeds the flux to the welding area to form a flux layer. The welding head (34) causes an arc to be generated between the continuously fed welding wire and the welded part under the flux layer. The heat of the arc melts the welding wire, the pipe fitting and the flux to form a metal molten pool. At the same time, the two pipes to be welded are driven by the support mechanism (2) to rotate synchronously and slowly in the same direction, and the rotation direction is towards the shielding member (43). S5: Weld formation. As the pipe rotates, the metal molten pool gradually rotates towards the shielding member (43). During this process, the unmelted flux is blocked by the shielding member (43) and does not immediately separate from the metal molten pool, so it continues to cover the metal molten pool until it exits the covering range of the shielding member (43), and then the unmelted flux drops from the pipe. During this process, the metal molten pool cools and forms.

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