A flared X-type groove welding joint and process method

Abstract

The application discloses a flared X-shaped groove welding joint and a process method, wherein the joint comprises a front groove and a back groove in a symmetrical structure; a land is arranged in the direction of the front groove from the back groove root face cleaning starting position; the back groove is locally provided with a platform; the platform is provided with an opening, and the root face cleaning operation is facilitated. The welding depth of the front groove is h1=t / 2+x-c / 2; the welding depth of the back groove is h2=t / 2-x+c / 2; wherein t is the plate thickness, x is the root face cleaning depth, and c is the land thickness. The process method comprises joint design, joint assembly, front groove and back groove welding; the flared X-shaped groove welding joint and the process method have the advantages of fewer root face cleaning steps, unchanged root face angle after root face cleaning, fewer internal defects of the welding seam, high angle trimming efficiency, and the welding quality and the welding operation efficiency are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and specifically relates to a flared X-groove welding joint and its process. Background Technology

[0002] The coupler mounting base of high-speed trains is made of aluminum alloy. Due to its high load-bearing strength, the welding quality requirements after the coupler mounting base assembly are high, necessitating internal flaw detection (ultrasonic and radiographic testing). Currently, the joint typically uses a type I joint, welded using friction stir welding. However, due to limitations in the production capacity of friction stir welding equipment, MIG automatic welding technology is gradually being adopted as a replacement, and the welded joints are correspondingly converted to type X joints. However, in current train production, to ensure the welding quality of the X-type joint weld, root cleaning is often used before reverse welding to eliminate root defects. This method suffers from numerous problems, including a cumbersome root cleaning process, significant changes in the root cleaning angle, low angle adjustment efficiency, and numerous internal weld defects.

[0003] Patent application number CN201410587645.X discloses a welding process for medium-thick plates with an X-groove but without root pass. This process mainly uses submerged arc welding when the back pass is not cleared. The steps of the welding process for medium-thick plates with an X-groove but without root pass include: A. Pre-welding cutting and assembly; B. Front root pass welding; C. Front low-current submerged arc welding; D. Back pass welding; E. Remaining filler and cover pass welds. The above-mentioned technical solution for welding medium-thick plates with an X-groove but without root pass is suitable for welding welds of 10mm or more. It is not sensitive to differences in groove quality, assembly gap, misalignment, and surface roughness. However, it is not suitable for flared X-groove welded joints.

[0004] Therefore, this application is hereby submitted. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art. The first objective of the present invention is to provide a flared X-groove welding joint.

[0006] The second objective of this invention is to provide a process method for flared X-groove welded joints, which solves many problems such as cumbersome root cleaning steps, large changes in root cleaning angle, low efficiency of angle adjustment, and numerous internal defects in the weld.

[0007] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is: a process method for a flared X-type bevel welding joint; the process method includes joint design, joint assembly, and welding of the front and back bevels; wherein, the joint design method includes:

[0008] The front bevel and the back bevel are designed with the center line of the plate thickness as the end line for root clearing.

[0009] The location of the starting line for root cleaning on the reverse bevel is determined based on the depth of root cleaning.

[0010] The shape of the front bevel is modified according to the position of the root clearing starting line and the preset bevel angle;

[0011] The shape of the reverse bevel is modified according to the location of the root clearing termination line and the preset bevel angle.

[0012] Using the above scheme, with the plate thickness centerline as the root cleaning termination line position 8, the upper width of the reverse bevel can be widened in advance according to the root cleaning depth and the preset bevel angle, so that the single-sided bevel angle remains unchanged at 35° after connecting with the bottom of the root-cleaned bevel, eliminating the influence of root cleaning operation on the bevel angle and improving welding quality. At the same time, using the plate thickness centerline as the root cleaning termination line position 8 can ensure that the shape of the front and back bevels is symmetrical after root cleaning, which is beneficial to reducing welding deformation. The purpose of increasing the bevel width is to prevent the bevel angle from changing after reverse root cleaning, ensuring that the bevel angle meets the requirements of ISO9692-3 standard, and removing the ineffective base material cutting area through the first bevel processing, reducing the amount of root cleaning work.

[0013] Furthermore, the methods for connector design also include:

[0014] The reverse bevel is set with a platform according to the position of the root cleaning starting line to facilitate stable root cleaning operation of the pen-shaped milling cutter;

[0015] Design a blunt edge, with the thickness of the blunt edge designed from the starting line of the reverse bevel towards the front bevel.

[0016] The above design incorporates a blunt edge to prevent burn-through during automatic welding. A local platform is installed on the reverse bevel, with an opening in the center to facilitate stable end mill cleaning operations.

[0017] Furthermore, following the joint design, the process also includes joint assembly; the methods for joint assembly include:

[0018] Assembly is performed using uphill welding;

[0019] After assembly, positioning and welding are performed for fixation;

[0020] A temporary stainless steel liner is added to the reverse bevel side.

[0021] The above solution employs uphill welding, which involves adding a 12mm backing plate at the arc termination end to prevent the molten pool from flowing in front of the arc and causing poor fusion.

[0022] Furthermore, the process after joint assembly also includes welding the front and back bevels; the methods for welding the front and back bevels include:

[0023] The front bevel welding is performed using MIG automatic welding for the first layer and the second layer of the front bevel.

[0024] The reverse bevel cleaning treatment.

[0025] Furthermore, during the second layer of filler welding of the front bevel, an oscillation is added, and the oscillation width is set not to exceed the width of the first layer of root pass weld of the front bevel.

[0026] Set the swing pause time on both sides of the weld.

[0027] Furthermore, the reverse bevel cleaning process involves using a pen-type milling cutter to clean the roots from the opening in the middle of the joint platform outwards to both sides according to a set cleaning depth. During the cleaning process, the cleaning depth is checked to ensure that it is within a reasonable range, thereby eliminating the impact of cleaning on the bevel angle.

[0028] By adopting the above method and ensuring that the root cleaning depth does not exceed 3mm according to the set depth, the root cleaning depth can be well controlled within a reasonable range by detecting the root cleaning depth during the root cleaning process.

[0029] Furthermore, the reverse bevel welding is performed after the reverse bevel cleaning treatment.

[0030] The reverse bevel welding is performed using MIG automatic welding for the first layer and the second layer of the reverse bevel.

[0031] After the reverse bevel is welded, the remaining layers are welded in an alternating sequence of the front bevel and the reverse bevel.

[0032] Using the above scheme, the welding sequence of the remaining layers is carried out in the alternating order of the front bevel and the back bevel, so as to reduce the amount of deformation after welding.

[0033] Furthermore, during the second layer of filler welding of the reverse bevel, an oscillation is added, and the oscillation width is set not to exceed the width of the first layer of root pass weld of the reverse bevel.

[0034] Set the swing pause time on both sides of the weld.

[0035] The present invention also provides a flared X-type bevel welding joint; the joint includes a front bevel and a back bevel with a symmetrical structure; a blunt edge is provided from the root cleaning starting line of the back bevel toward the front bevel; a platform is provided in part of the back bevel; the platform is provided with an opening to facilitate root cleaning operation.

[0036] The above scheme results in a symmetrical bevel shape between the front and back bevels, which helps reduce welding deformation. A platform is set in a part of the back bevel, and an opening is set in the middle of the platform to facilitate the stable cleaning operation of the pen-shaped milling cutter.

[0037] Furthermore, the welding depth of the front bevel is h1 = t / 2 + xc / 2; the welding depth of the reverse bevel is h2 = t / 2 - x + c / 2; where t is the plate thickness, x is the root cleaning depth, and c is the blunt edge thickness.

[0038] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0039] This invention, through the design of a flared X-groove welding joint and its process, has the advantages of fewer root cleaning steps, no change in angle after root cleaning, fewer internal defects in the weld, and high angle adjustment efficiency, which significantly improves welding quality and welding operation efficiency.

[0040] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0041] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0042] Figure 1 This is a schematic diagram of the front bevel and back bevel structure in a flared X-type bevel welding joint of the present invention;

[0043] Figure 2 This is a diagram illustrating the plate thickness, root cleaning depth, and blunt edge thickness of a flared X-type bevel welded joint according to the present invention.

[0044] Figure 3 This is a diagram showing the positions of the root cleaning start line and the root cleaning end line in a flared X-type bevel welded joint according to the present invention.

[0045] Figure 4 This is a schematic diagram of the gasket installation position in a flared X-type bevel welded joint according to the present invention;

[0046] Figure 5 This is a schematic diagram of the platform and opening positions in a flared X-type bevel welding joint according to the present invention;

[0047] Figure 6 This is a schematic diagram of the reverse bevel before root cleaning treatment in a flared X-type bevel welded joint according to the present invention.

[0048] Figure 7 This is a schematic diagram illustrating the effect of root cleaning treatment on the reverse bevel in a flared X-type bevel welded joint according to the present invention.

[0049] Figure 8 This is a schematic diagram of the process method for a flared X-type bevel welding joint according to the present invention.

[0050] Figure 9 This is a schematic diagram of the joint design logic in the process method of a flared X-type groove welding joint of the present invention;

[0051] Figure 10 This is a schematic diagram of the assembly logic of a flared X-groove welding joint according to the present invention.

[0052] Figure 11 This is a schematic diagram of the front bevel welding logic in the process method of a flared X-type bevel welding joint of the present invention.

[0053] Figure 12 This is a schematic diagram of the reverse bevel welding logic in the process method of a flared X-type bevel welding joint of the present invention.

[0054] In the diagram: 1. Front bevel; 2. Back bevel; 3. Obtuse edge; 4. Platform; 5. Opening; 6. Pad; 7. Root cleaning start line position; 8. Root cleaning end line position.

[0055] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0057] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0058] like Figure 1 , Figure 2 , Figure 3 and Figure 5As shown, in one embodiment, the present invention provides a flared X-type bevel welding joint; the joint includes a front bevel 1 and a back bevel 2 with a symmetrical structure; a blunt edge 3 is provided from the root cleaning starting line 7 of the back bevel 2 toward the front bevel 1; a platform 4 is provided in a partial part of the back bevel 2; the platform 4 is provided with an opening 5 to facilitate root cleaning operations.

[0059] The upper width of the reverse bevel is widened in advance according to the root cleaning depth and preset bevel angle so that the bevel angle on one side remains unchanged at 35° after connecting with the bottom of the bevel after root cleaning; adding a blunt edge is to prevent weld burn-through problems in automatic welding. A local platform is set on the reverse bevel, and an opening is set in the middle of the platform to facilitate stable root cleaning operation of the pen-shaped milling cutter.

[0060] Compared to the conventional X-type joint, the bevel width is increased to prevent the bevel angle from changing after the reverse root cleaning, ensure that the bevel angle meets the requirements of ISO9692-3 standard, and remove the invalid parent material cutting area through the first bevel processing, thereby reducing the amount of root cleaning work.

[0061] Setting a blunt edge 3 is to prevent weld burn-through in automatic welding. A platform 4 is set in a local part of the reverse bevel 2, and an opening 5 is set in the middle of the platform 4 to facilitate stable root cleaning operation of the pen-shaped milling cutter;

[0062] The height of platform 4 should not be too large, as this will increase the amount of root cleaning work. The height of platform 4 can be set in the range of 1mm-3mm, with 2mm being the preferred setting. This can ensure the formation of the root weld of the bevel 1 on the front side while minimizing the amount of root cleaning work.

[0063] Wherein, the welding depth of the front bevel 1 h1=t / 2+xc / 2; the welding depth of the back bevel 2 h2=t / 2-x+c / 2; where t is the plate thickness, x is the root cleaning depth, and c is the blunt edge thickness.

[0064] like Figure 3 , Figure 4 , Figure 8 , Figure 9 , Figure 10 and Figure 11 As shown, in another embodiment, the present invention provides a process method for a flared X-type bevel welded joint; the process method includes joint design, joint assembly, and welding of the front bevel 1 and the back bevel 2; wherein, the joint design method includes:

[0065] Design the front bevel 1 and the back bevel 2 with the center line of the plate thickness as the end point of the root clearing position 8.

[0066] Based on the depth of root clearing, determine the position of the root clearing starting line 7 on the reverse bevel 2;

[0067] The shape of the front bevel 1 is modified according to the starting line position 7 of the root clearing and the preset bevel angle;

[0068] The shape of the reverse bevel 2 is modified according to the location 8 of the root clearing termination line and the preset bevel angle.

[0069] The reverse bevel 2 is set with a platform at the starting line position 7 of the root clearing. The platform height is 2mm, which facilitates the stable root clearing operation of the pen-shaped milling cutter.

[0070] Design blunt edge 3, and design the blunt edge thickness from the position 7 of the root clearing starting line of the reverse bevel 2 towards the front bevel 1.

[0071] By using the plate thickness centerline as the end point 8 for root cleaning, the upper width of the reverse bevel can be widened in advance according to the root cleaning depth and preset bevel angle. This ensures that the bevel angle on one side remains constant at 35° after connecting with the bottom of the root-cleaned bevel, eliminating the influence of root cleaning on the bevel angle and improving welding quality. Simultaneously, using the plate thickness centerline as the end point 8 ensures a symmetrical structure of the front and back bevels after root cleaning, which helps reduce welding deformation. The increased bevel width aims to prevent changes in the bevel angle after reverse root cleaning, ensuring the bevel angle meets the ISO9692-3 standard requirements and removing ineffective base material cutting areas through initial bevel processing, reducing the amount of root cleaning work. The blunt edge design prevents burn-through issues in automatic welding. A local platform is set on the reverse bevel, with an opening in the center to facilitate stable root cleaning operations with the pen-shaped milling cutter.

[0072] Following joint design, the process also includes joint assembly; joint assembly methods include:

[0073] Assembly is performed using uphill welding;

[0074] After assembly, positioning and welding are performed for fixation;

[0075] Add a temporary stainless steel liner 6 to both sides of the reverse bevel.

[0076] Uphill welding is adopted, that is, a 12mm backing plate is added at the end of the arc to prevent the metal in the molten pool from flowing to the front of the arc, which would lead to poor fusion.

[0077] The assembly gap should ideally be 2mm to ensure complete fusion.

[0078] A temporary pad 6 is added to the reverse bevel 2; the thickness of the temporary pad 6 is equal to the distance from the root clearing starting line position 7 to the surface of the reverse bevel 2.

[0079] After the joint assembly, the process also includes welding the front bevel 1 and the back bevel 2; the method for welding the front bevel 1 and the back bevel 2 includes:

[0080] The first layer and the second layer of the front bevel 1 were welded using MIG automatic welding.

[0081] Root cleaning treatment on the reverse bevel 2.

[0082] Among them, when welding the second layer of filler weld of the front bevel 1, the oscillation is increased and the oscillation width is set not to exceed the width of the first layer root weld of the front bevel 1.

[0083] Setting oscillation pause times on both sides of the weld increases the sidewall penetration and reduces the occurrence of sidewall incomplete fusion defects;

[0084] Root cleaning treatment on the reverse bevel 2, with the root cleaning depth controlled within 3mm;

[0085] The term "MIG automatic welding" refers to a welding method in which an inert gas is used to coat the weld area, stabilizing the arc and preventing changes in weld quality. The arc heat melts the metal of the weld area, and a welding rod is fed in to connect the weld. It is also commonly known as semi-automatic welding, gas coated arc welding, or carbon dioxide arc welding.

[0086] like Figure 3 , Figure 4 , Figure 8 , Figure 9 , Figure 10 and Figure 11 As shown, in one embodiment, the present invention provides a process method for a flared X-type bevel welded joint; the process method includes joint design, joint assembly, and welding of the front bevel 1 and the back bevel 2; wherein, the joint design method includes:

[0087] Design the front bevel 1 and the back bevel 2 with the center line of the plate thickness as the end point of the root clearing position 8.

[0088] Based on the depth of root clearing, determine the position of the root clearing starting line 7 on the reverse bevel 2;

[0089] The shape of the front bevel 1 is modified according to the starting line position 7 of the root clearing and the preset bevel angle;

[0090] The shape of the reverse bevel 2 is modified according to the location 8 of the root clearing termination line and the preset bevel angle.

[0091] The reverse bevel 2 is set with a platform at the starting line position 7 of the root clearing. The platform height is 2mm, which facilitates the stable root clearing operation of the pen-shaped milling cutter.

[0092] Design blunt edge 3, and design the blunt edge thickness from the position 7 of the root clearing starting line of the reverse bevel 2 towards the front bevel 1.

[0093] By using the plate thickness centerline as the end point 8 for root cleaning, the upper width of the reverse bevel can be widened in advance according to the root cleaning depth and preset bevel angle. This ensures that the bevel angle on one side remains constant at 35° after connecting with the bottom of the root-cleaned bevel, eliminating the influence of root cleaning on the bevel angle and improving welding quality. Simultaneously, using the plate thickness centerline as the end point 8 ensures a symmetrical structure of the front and back bevels after root cleaning, which helps reduce welding deformation. The increased bevel width aims to prevent changes in the bevel angle after reverse root cleaning, ensuring the bevel angle meets the ISO9692-3 standard requirements and removing ineffective base material cutting areas through initial bevel processing, reducing the amount of root cleaning work. The blunt edge design prevents burn-through issues in automatic welding. A local platform is set on the reverse bevel, with an opening in the center to facilitate stable root cleaning operations with the pen-shaped milling cutter.

[0094] Following joint design, the process also includes joint assembly; joint assembly methods include:

[0095] Assembly is performed using uphill welding;

[0096] After assembly, positioning and welding are performed for fixation;

[0097] Add a temporary stainless steel liner 6 to both sides of the reverse bevel.

[0098] Uphill welding is adopted, that is, a 12mm backing plate is added at the end of the arc to prevent the metal in the molten pool from flowing to the front of the arc, which would lead to poor fusion.

[0099] The assembly gap should ideally be 2mm to ensure complete fusion.

[0100] A temporary pad 6 is added to the reverse bevel 2; the thickness of the temporary pad 6 is equal to the distance from the root clearing starting line position 7 to the surface of the reverse bevel 2.

[0101] After the joint assembly, the process also includes welding the front bevel 1 and the back bevel 2; the method for welding the front bevel 1 and the back bevel 2 includes:

[0102] The first layer and the second layer of the front bevel 1 were welded using MIG automatic welding.

[0103] Root cleaning treatment on the reverse bevel 2.

[0104] Among them, the root cleaning treatment of the reverse bevel 2 is to use a pen-type milling cutter to clean the roots from the opening 5 in the middle of the joint platform 4 to both sides according to the set root cleaning depth; during the root cleaning process, the root cleaning depth is detected to ensure that the root cleaning depth is within a reasonable range and to eliminate the influence of root cleaning on the bevel angle.

[0105] According to the set root cleaning depth, ensure that the depth does not exceed 3mm. Detecting the root cleaning depth during the root cleaning process can effectively control the root cleaning depth within a reasonable range.

[0106] like Figure 3 , Figure 4 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown, in one embodiment, the present invention provides a process method for a flared X-type bevel welded joint; the process method includes joint design, joint assembly, and welding of the front bevel 1 and the back bevel 2; wherein, the joint design method includes:

[0107] Design the front bevel 1 and the back bevel 2 with the center line of the plate thickness as the end point of the root clearing position 8.

[0108] Based on the depth of root clearing, determine the position of the root clearing starting line 7 on the reverse bevel 2;

[0109] The shape of the front bevel 1 is modified according to the starting line position 7 of the root clearing and the preset bevel angle;

[0110] The shape of the reverse bevel 2 is modified according to the location 8 of the root clearing termination line and the preset bevel angle.

[0111] The reverse bevel 2 is set with a platform at the starting line position 7 of the root clearing. The platform height is 2mm, which facilitates the stable root clearing operation of the pen-shaped milling cutter.

[0112] Design blunt edge 3, and design the blunt edge thickness from the position 7 of the root clearing starting line of the reverse bevel 2 towards the front bevel 1.

[0113] By using the plate thickness centerline as the end point 8 for root cleaning, the upper width of the reverse bevel can be widened in advance according to the root cleaning depth and preset bevel angle. This ensures that the bevel angle on one side remains constant at 35° after connecting with the bottom of the root-cleaned bevel, eliminating the influence of root cleaning on the bevel angle and improving welding quality. Simultaneously, using the plate thickness centerline as the end point 8 ensures a symmetrical structure of the front and back bevels after root cleaning, which helps reduce welding deformation. The increased bevel width aims to prevent changes in the bevel angle after reverse root cleaning, ensuring the bevel angle meets the ISO9692-3 standard requirements and removing ineffective base material cutting areas through initial bevel processing, reducing the amount of root cleaning work. The blunt edge design prevents burn-through issues in automatic welding. A local platform is set on the reverse bevel, with an opening in the center to facilitate stable root cleaning operations with the pen-shaped milling cutter.

[0114] Following joint design, the process also includes joint assembly; joint assembly methods include:

[0115] Assembly is performed using uphill welding;

[0116] After assembly, positioning and welding are performed for fixation;

[0117] Add a temporary stainless steel liner 6 to both sides of the reverse bevel.

[0118] Uphill welding is adopted, that is, a 12mm backing plate is added at the end of the arc to prevent the metal in the molten pool from flowing to the front of the arc, which would lead to poor fusion.

[0119] The assembly gap should ideally be 2mm to ensure complete fusion.

[0120] A temporary pad 6 is added to the reverse bevel 2; the thickness of the temporary pad 6 is equal to the distance from the root clearing starting line position 7 to the surface of the reverse bevel 2.

[0121] After the joint assembly, the process also includes welding the front bevel 1 and the back bevel 2; the method for welding the front bevel 1 and the back bevel 2 includes:

[0122] The first layer and the second layer of the front bevel 1 were welded using MIG automatic welding.

[0123] Root cleaning treatment on the reverse bevel 2.

[0124] After cleaning the root of the reverse bevel 2, weld the reverse bevel 2.

[0125] The first layer and the second layer of the reverse bevel 2 are welded using MIG automatic welding.

[0126] Among them, when welding the second layer of filler weld of the reverse bevel 2, the oscillation is increased and the oscillation width is set not to exceed the width of the first layer root weld of the reverse bevel 2.

[0127] Setting oscillation pause times on both sides of the weld increases the sidewall penetration and reduces the occurrence of sidewall incomplete fusion defects;

[0128] Root cleaning treatment on the reverse bevel 2, with the root cleaning depth controlled within 3mm;

[0129] The term "MIG automatic welding" refers to a welding method in which an inert gas is used to coat the weld area, stabilizing the arc and preventing changes in weld quality. The arc heat melts the metal of the weld area, and a welding rod is fed in to connect the weld. It is also commonly known as semi-automatic welding, gas coated arc welding, or carbon dioxide arc welding.

[0130] like Figure 3 , Figure 4 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown, in one embodiment, the present invention provides a process method for a flared X-type bevel welded joint; the process method includes joint design, joint assembly, and welding of the front bevel 1 and the back bevel 2; wherein, the joint design method includes:

[0131] Design the front bevel 1 and the back bevel 2 with the center line of the plate thickness as the end point of the root clearing position 8.

[0132] Based on the depth of root clearing, determine the position of the root clearing starting line 7 on the reverse bevel 2;

[0133] The shape of the front bevel 1 is modified according to the starting line position 7 of the root clearing and the preset bevel angle;

[0134] The shape of the reverse bevel 2 is modified according to the location 8 of the root clearing termination line and the preset bevel angle.

[0135] The reverse bevel 2 is set with a platform at the starting line position 7 of the root clearing. The platform height is 2mm, which facilitates the stable root clearing operation of the pen-shaped milling cutter.

[0136] Design blunt edge 3, and design the blunt edge thickness from the position 7 of the root clearing starting line of the reverse bevel 2 towards the front bevel 1.

[0137] By using the plate thickness centerline as the end point 8 for root cleaning, the upper width of the reverse bevel can be widened in advance according to the root cleaning depth and preset bevel angle. This ensures that the bevel angle on one side remains constant at 35° after connecting with the bottom of the root-cleaned bevel, eliminating the influence of root cleaning on the bevel angle and improving welding quality. Simultaneously, using the plate thickness centerline as the end point 8 ensures a symmetrical structure of the front and back bevels after root cleaning, which helps reduce welding deformation. The increased bevel width aims to prevent changes in the bevel angle after reverse root cleaning, ensuring the bevel angle meets the ISO9692-3 standard requirements and removing ineffective base material cutting areas through initial bevel processing, reducing the amount of root cleaning work. The blunt edge design prevents burn-through issues in automatic welding. A local platform is set on the reverse bevel, with an opening in the center to facilitate stable root cleaning operations with the pen-shaped milling cutter.

[0138] Following joint design, the process also includes joint assembly; joint assembly methods include:

[0139] Assembly is performed using uphill welding;

[0140] After assembly, positioning and welding are performed for fixation;

[0141] Add a temporary stainless steel liner 6 to both sides of the reverse bevel.

[0142] Uphill welding is adopted, that is, a 12mm backing plate is added at the end of the arc to prevent the metal in the molten pool from flowing to the front of the arc, which would lead to poor fusion.

[0143] The assembly gap should ideally be 2mm to ensure complete fusion.

[0144] A temporary pad 6 is added to the reverse bevel 2; the thickness of the temporary pad 6 is equal to the distance from the root clearing starting line position 7 to the surface of the reverse bevel 2.

[0145] After the joint assembly, the process also includes welding the front bevel 1 and the back bevel 2; the method for welding the front bevel 1 and the back bevel 2 includes:

[0146] The first layer and the second layer of the front bevel 1 were welded using MIG automatic welding.

[0147] Root cleaning treatment on the reverse bevel 2.

[0148] After cleaning the root of the reverse bevel 2, weld the reverse bevel 2.

[0149] The first layer and the second layer of the reverse bevel 2 are welded using MIG automatic welding.

[0150] After the reverse bevel 2 is welded, the remaining layers are welded in the alternating order of the front bevel 1 and the reverse bevel 2.

[0151] Both the front bevel 1 and the back bevel 2 are welded in three layers and four passes.

[0152] The remaining layers are welded in an alternating sequence of front and back bevels to reduce post-weld deformation.

[0153] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process method for a flared X-groove welded joint, characterized in that, The process includes joint design, joint assembly, and welding of the front bevel (1) and the back bevel (2); wherein, the joint design method includes: Design the front bevel (1) and the back bevel (2) with the plate thickness center line as the root clearing termination line position (8). The location of the root clearing starting line (7) of the reverse bevel (2) is determined according to the root clearing depth. The shape of the front bevel (1) is modified according to the position of the root clearing starting line (7) and the preset bevel angle; The shape of the reverse bevel (2) is modified according to the position of the root clearing termination line (8) and the preset bevel angle; The reverse bevel (2) is set with a platform according to the position of the root clearing starting line (7), and the platform (4) is provided with an opening (5) to facilitate root clearing operations; Design the blunt edge (3), and design the blunt edge thickness from the starting line position (7) of the reverse bevel (2) towards the front bevel (1); The welding depth of the front bevel (1) is h1=t / 2+xc / 2; the welding depth of the back bevel (2) is h2=t / 2-x+c / 2; where t is the plate thickness, x is the root cleaning depth, and c is the blunt edge thickness. By using the center line of the plate thickness as the end point of root clearing (8), the upper width of the reverse bevel (2) can be widened in advance according to the root clearing depth and the preset bevel angle, so that the bevel angle on one side remains unchanged after connecting with the bottom of the bevel after root clearing.

2. The process method for a flared X-groove welded joint according to claim 1, characterized in that, Following joint design, the process also includes joint assembly; joint assembly methods include: Assembly is performed using uphill welding; After assembly, positioning and welding are performed for fixation; A temporary stainless steel liner (6) is added to the reverse bevel (2) side.

3. The process method for a flared X-groove welded joint according to claim 2, characterized in that, After the joint is assembled, the process also includes welding the front bevel (1) and the back bevel (2); the method of welding the front bevel (1) and the back bevel (2) includes: The front bevel (1) is welded using MIG automatic welding to weld the first layer of the front bevel (1) and the second layer of the front bevel (1); The reverse bevel (2) is treated with root cleaning.

4. The process method for a flared X-groove welded joint according to claim 3, characterized in that, When welding the second layer of filler weld of the front bevel (1), add oscillation, and set the oscillation width to not exceed the width of the first layer root weld of the front bevel (1); Set the swing pause time on both sides of the weld.

5. The process method for a flared X-groove welded joint according to claim 3, characterized in that, The back bevel (2) cleaning process is carried out by using a pen-type milling cutter to clean the roots from the opening (5) in the middle of the joint platform (4) to both sides according to the set cleaning depth; the cleaning depth is detected during the cleaning process to ensure that the cleaning depth is within a reasonable range and to eliminate the influence of cleaning on the bevel angle.

6. The process method for a flared X-groove welded joint according to claim 3, characterized in that, After the root cleaning treatment of the reverse bevel (2), the welding of the reverse bevel (2) is performed; The reverse bevel (2) is welded using MIG automatic welding to weld the first layer and the second layer of the reverse bevel (2); After the reverse bevel (2) is welded, the remaining layers are welded in the order of alternating between the front bevel (1) and the reverse bevel (2).

7. The process method for a flared X-groove welded joint according to claim 6, characterized in that, When welding the second layer of filler weld of the reverse bevel (2), add oscillation, and set the oscillation width to not exceed the width of the first layer root weld of the reverse bevel (2); Set the swing pause time on both sides of the weld.

8. A flared X-groove welded joint designed using the process method described in claim 1, characterized in that, The joint includes a front bevel (1) and a back bevel (2) with a symmetrical structure; a blunt edge (3) is provided from the root clearing starting line position (7) of the back bevel (2) toward the front bevel (1); a platform (4) is provided in part of the back bevel (2).

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