An automated welding process for irregular bevel isolation layers

Abstract

This invention relates to the field of isolation layer welding technology, and proposes an automatic welding process for an irregularly shaped bevel isolation layer, comprising the following steps: opening a pipe hole on the shell; selecting an inner auxiliary cylinder and an outer auxiliary cylinder, the inner sidewall of the inner auxiliary cylinder, the inner sidewall of the outer auxiliary cylinder, and the hole wall of the pipe hole forming a continuous annular wall structure; automatically welding a nickel-based isolation layer on the annular wall structure using a welding torch; removing excess isolation layer from the inner auxiliary cylinder, the outer auxiliary cylinder, and the outside of the hole wall of the pipe hole, with the two end faces of the remaining isolation layer flush with the inner and outer sidewalls of the shell, respectively; machining an isolation layer bevel on the remaining isolation layer for subsequent assembly and welding of the pipe. This invention solves the problem in the prior art where automatic welding is impossible due to the spatial limitations of the irregularly shaped bevel structure, and also improves welding quality and efficiency, while significantly reducing manufacturing costs and rework risks.

Description

Technical Field

[0001] This invention relates to the field of isolation layer welding technology, and more specifically, to an automatic welding process for isolation layers with irregular bevels. Background Technology

[0002] Currently, large pressure vessel shells are designed with various insert-type fully penetrated nozzles. The opening direction on the shell varies according to the nozzle angle. For non-radial / non-centripetal openings, a non-standard single V-groove with a continuously varying angle along the circumference of the hole is typically designed, as shown in the attached figure. Figure 1 and Figure 2 The diagram shows the bevel of the nozzle on the shell 1 of a spherical container. To ensure the reliability of subsequent welding to the stainless steel nozzle 2, the drawings generally require a nickel-based insulating layer 3 to be deposited on the bevel surface.

[0003] Currently, automated welding is mainly used for structures with regular shapes, such as regular rotating bodies. For irregularly shaped bevels with limited space, automated welding is not suitable. Traditional isolation layer cladding processes generally employ manual welding using shielded metal arc welding. However, this traditional method has the following significant technical drawbacks: (1) Poor quality stability: The space of the irregular bevel is limited and the angle is variable. When manually welding, the workpiece posture needs to be adjusted many times to adapt to the welding operation. The welding process is discontinuous, the welding operation is difficult, and it is easy to produce defects such as slag inclusion and incomplete fusion. In addition, the penetration test (PT) pass rate of the nickel-based isolation layer is low and the rework rate is high.

[0004] (2) Low efficiency: Manual multi-layer and multi-pass welding is slow and the welding process is fragmented, which has become a bottleneck process that restricts the overall equipment manufacturing progress.

[0005] (3) Harsh working environment: The welding fumes are large and the radiant heat is high, which poses a serious threat to the occupational health of welders.

[0006] (4) High risk of subsequent processes: During the inter-pass grinding and cleaning process of the later-stage pipe welding, the already welded isolation layer is easily damaged, which can easily lead to a reduction in the thickness of the isolation layer. Once rework is required, the pipe must be cut off and the isolation layer must be reworked and heat-treated. The pipe must be remade and welded. The rework time is long and will have a significant impact on the project schedule.

[0007] (5) High testing cost: The nickel-based isolation layer needs to be radiographically inspected (RT), and the RT testing of the irregular bevel requires a customized compensation block. The compensation block needs to be processed into a complex irregular curved surface to fit the isolation layer, which makes the processing extremely difficult and the manufacturing cost extremely high.

[0008] In summary, existing technologies cannot meet the stringent requirements of equipment for welding quality, production efficiency, and cost control of nickel-based insulating layers, and there is an urgent need to develop a new automated overlay welding process. Summary of the Invention

[0009] The purpose of this invention is to provide an automatic welding process for the isolation layer of irregular bevels, which can solve the problem that automatic welding cannot be achieved due to the spatial structure limitations of irregular bevels in the prior art. Moreover, it can improve welding quality and efficiency, and significantly reduce manufacturing costs and rework risks.

[0010] The technical solution adopted in this invention is as follows: This application provides an automated welding process for an isolation layer with an irregular bevel, comprising the following steps: S1: A pipe hole is made on the casing; S2: Select an inner auxiliary cylinder and an outer auxiliary cylinder. The inner diameter of the inner auxiliary cylinder, the inner diameter of the outer auxiliary cylinder, and the diameter of the connecting pipe hole are all the same. The outer auxiliary cylinder is fixed to the outer wall of the shell, and the inner auxiliary cylinder is fixed to the inner wall of the shell. Ensure that the inner auxiliary cylinder, the outer auxiliary cylinder, and the connecting pipe hole are coaxial, so that the inner wall of the inner auxiliary cylinder, the inner wall of the outer auxiliary cylinder, and the hole wall of the connecting pipe hole form a continuous and uninterrupted annular wall structure. S3: A uniform nickel-based isolation layer is automatically deposited on the annular wall structure using a welding torch. The isolation layer covers the hole wall of the pipe and extends to the inner wall of the inner auxiliary cylinder and the inner wall of the outer auxiliary cylinder, respectively. S4: Remove the excess isolation layer outside the inner auxiliary cylinder, outer auxiliary cylinder, and pipe hole, so that the two end faces of the remaining isolation layer are flush with the inner and outer side walls of the shell, respectively.

[0011] Furthermore, in this invention, in step S1, a pipe hole is formed on the housing by machining, and excess material is retained after the hole is formed; In step S4, the remaining material from the opening is made into a flaw detection compensation block. The shape of the flaw detection compensation block is adapted to the aperture of the isolation layer. The flaw detection compensation block is placed in the opening area of ​​the isolation layer for flaw detection.

[0012] Furthermore, in this invention, if the flaw detection is qualified, the bevel of the remaining isolation layer is processed; if the flaw detection is unqualified, the defective position is removed and then repaired by manual welding. After repair welding, the flaw detection is performed again until the flaw detection is qualified.

[0013] Furthermore, in this invention, the processed isolation layer bevel is a K-shaped bevel.

[0014] Furthermore, in this invention, in step S3, before welding, the housing is installed on the welding positioner and the welding torch is placed inside the annular wall structure; during welding, the welding positioner is used to make the housing, together with the inner auxiliary cylinder and the outer auxiliary cylinder, rotate synchronously and about the axis of the pipe hole as the rotation axis. During the rotation, the welding torch moves along the axial direction of the pipe hole to perform automatic welding.

[0015] Compared with the prior art, the present invention has at least the following advantages or beneficial effects: This application provides an automatic welding process for the isolation layer of irregular bevels, which can solve the problem that automatic welding cannot be achieved in the prior art due to the spatial structure limitation of irregular bevels. It can also improve welding quality and efficiency, and significantly reduce manufacturing costs and rework risks. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional view of the nozzle after it has been welded to the housing in the prior art; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 This is a cross-sectional view of the isolation layer after welding, provided in an embodiment of the present invention. Figure 4 This is a cross-sectional view of the isolation layer, inner auxiliary cylinder, and outer auxiliary cylinder after milling, as provided in an embodiment of the present invention. Figure 5 This is a cross-sectional view of the flaw detection compensation block placed after the isolation layer, as provided in an embodiment of the present invention. Figure 6 This is a cross-sectional view of the isolation layer after the beveling process is completed, as provided in an embodiment of the present invention.

[0018] Icons: 1-Shell; 2-Connecting pipe; 3-Isolation layer; 4-Connecting pipe hole; 5-Inner auxiliary cylinder; 6-Outer auxiliary cylinder; 7-Annular wall structure; 8-Isolation layer bevel; 9-Flaw detection compensation block. Detailed Implementation

[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings. Example

[0020] Please refer to Figures 3-6This embodiment provides an automatic welding process for an isolation layer with an irregular bevel, including the following steps: S1: A pipe hole 4 is opened on the housing 1. When opening the pipe hole 4, the pipe hole 4 can be opened on the housing 1 by machining with a machine tool, and the opening material is retained. The direction of the pipe hole 4 is that its axis is vertical.

[0021] S2: Because the axis of the connecting hole 4 is vertical and not machined radially, there is a continuous height difference between the top and bottom of the machined connecting hole 4. Therefore, an inner auxiliary cylinder 5 and an outer auxiliary cylinder 6 are selected. The inner diameter of the inner auxiliary cylinder 5, the inner diameter of the outer auxiliary cylinder 6, and the diameter of the connecting hole 4 are all the same. The outer auxiliary cylinder 6 can be fixed to the outer wall of the shell 1 by spot welding, and the inner auxiliary cylinder 5 can be fixed to the inner wall of the shell 1 by spot welding. It is ensured that the inner auxiliary cylinder 5, the outer auxiliary cylinder 6, and the connecting hole 4 are coaxial, so that the inner wall of the inner auxiliary cylinder 5, the inner wall of the outer auxiliary cylinder 6, and the hole wall of the connecting hole 4 form a continuous and uninterrupted annular wall structure 7. For details, please refer to... Figure 3 As shown, in this embodiment, the inner auxiliary cylinder 5 and the outer auxiliary cylinder 6 simulate the inner wall of the cylinder, and "normalize" the spatial curved surface of the through-hole 4 into a regular rotating inner wall structure, namely the annular wall structure 7, thereby providing the automatic welding torch with a stable and continuous travel trajectory and a unified welding posture reference.

[0022] S3: Before welding, the housing 1 is installed on the welding positioner, and the welding torch is placed inside the annular wall structure 7. During welding, the welding positioner is used to make the housing 1, together with the inner auxiliary cylinder 5 and the outer auxiliary cylinder 6, rotate synchronously around the axis of the connecting hole 4. During the rotation, the welding torch moves along the axial direction of the connecting hole 4 to automatically build up the weld. The welding process is automatically completed according to the preset welding parameters and trajectory. In this way, a nickel-based isolation layer 3 of uniform thickness is automatically built up on the annular wall structure 7. The isolation layer 3 covers the hole wall of the connecting hole 4 and extends to the inner side wall of the inner auxiliary cylinder 5 and the inner side wall of the outer auxiliary cylinder 6 respectively. The welding torch can be a hot wire TIG welding torch, and the welding method can be hot wire TIG welding.

[0023] S4: As Figure 4 As shown, the excess isolation layer 3 on the outside of the inner auxiliary cylinder 5, outer auxiliary cylinder 6, and pipe hole 4 is milled off by machine tool machining, so that the two end faces of the remaining isolation layer 3 are flush with the inner and outer side walls of the shell 1, respectively. The weld seam of the completed isolation layer is subjected to flaw detection. During flaw detection, the edge of the remaining material is machined to form a flaw detection compensation block 9. The shape of the flaw detection compensation block 9 is adapted to the hole diameter of the isolation layer 3, such as... Figure 5As shown, the flaw detection compensation block 9 is placed in the opening area of ​​the isolation layer 3 for flaw detection. Radiographic testing (RT) can be used for flaw detection. After passing the flaw detection, the bevel 8 of the isolation layer is processed. If the flaw detection fails, the defective area is removed and then manually welded separately. Defect removal can be done by grinding or machining. After welding, flaw detection is performed again until the flaw detection is passed. To prevent the flaw detection compensation block 9 from falling out of the opening area of ​​the isolation layer 3, a protrusion can be welded to the top of the flaw detection compensation block 9 to abut against the outer wall of the housing 1 to prevent it from falling.

[0024] S5: After the flaw detection is qualified, the remaining isolation layer 3 is machined to form an isolation layer bevel 8 for subsequent assembly and welding of the connecting pipe 2, such as... Figure 6 As shown, the bevel 8 of the processed isolation layer preferably adopts a K-shaped bevel, which can ensure the thickness of the isolation layer 3. In this embodiment, the actual welding thickness of the isolation layer 3 can be greater than the design thickness, so as to leave a certain amount of grinding allowance for subsequent welding processes and prevent the isolation layer 3 from becoming thinner.

[0025] This section uses a nuclear island main equipment manufactured by a certain company as an example. The equipment is a spherical container with a shell material of SA-533BCl1+SA-240GR304L composite plate. Two water level measuring pipes need to be welded to the upper shell. The water level measuring pipe material is SA-182F316LN. After the bevel of the water level measuring pipe hole on the upper shell is overlaid with a nickel-based isolation layer, it undergoes overall heat treatment and is then welded to the water level measuring pipe. No further heat treatment is performed after welding.

[0026] The automatic welding of the nickel-based isolation layer at the bevel of the upper shell water level measuring pipe hole adopts the method of this patent, and the specific steps are as follows: A through-hole was machined into the housing, with its axis vertical, creating a straight space similar to the inner wall of the connector, thus clearing obstacles for the entry and movement of the automatic welding torch. Simultaneously, the design drawings explicitly increased the thickness of the isolation layer weld overlay, providing a safety margin for subsequent interpass grinding and root cleaning operations during connector welding.

[0027] Because the axis of the nozzle is not centripetal along the spherical shell, there is still a height difference in the circumferential direction of the nozzle. For example... Figure 3 As shown, an auxiliary tooling for "simulating the inner wall of the cylinder" was designed and installed. This tooling includes an inner auxiliary cylinder and an outer auxiliary cylinder. By matching the inner holes of the inner and outer auxiliary cylinders with the pipe holes, the originally uneven welding surface is transformed into a regular and continuous simulated inner wall surface of the cylinder, i.e., an annular wall structure, so that the welding torch can maintain a constant extension and stable posture during the welding process.

[0028] A fully automated argon arc welding system was used to automatically deposit a nickel-based isolation layer onto the inner wall of a regularly rotating body formed by auxiliary tooling. During the welding process, the rotation, oscillation, and wire feeding of the welding torch were controlled by a preset welding program, automatically completing multi-layer, multi-pass welding. Inspection revealed that the automatically welded isolation layer had an aesthetically pleasing surface finish, and PT testing showed no defects.

[0029] After the welding was completed, the inner and outer walls of the shell were machined to remove auxiliary tooling connection marks and excess isolation layer, creating a smooth surface. The inner wall of the isolation layer hole was also smoothed. Subsequently, radiographic testing (RT) was performed. The disc-shaped scrap material cut off during the initial hole drilling was simply machined to a size suitable for the inner diameter of the nickel-based isolation layer and used as a testing compensation block. The RT testing results showed that the internal quality of the isolation layer weld was completely qualified, with no defects exceeding the standard.

[0030] After passing the RT flaw detection, according to the drawing requirements, the final K-shaped variable angle bevel is machined on the already welded and smoothed isolation layer, in preparation for assembly and welding with the pipe.

[0031] Through the implementation steps, this embodiment successfully transformed the irregular bevel isolation layer from "manual operation" to "automatic welding", improving welding efficiency by more than 3 times, achieving 100% quality qualification, and significantly reducing the risks and manufacturing costs of subsequent processes.

[0032] Therefore, the automatic welding process for the isolation layer of irregular bevel provided in this application has the following beneficial effects: Significantly improved welding quality and consistency: By optimizing the bevel structure and using auxiliary tooling, the welding of complex irregular-shaped spaces is transformed into automated welding of regular rotating bodies, fundamentally solving the problem of the inability to automatically weld the isolation layer. The automated welding process parameters are stable, avoiding the uncertainties of manual operation and ensuring the consistency of nickel-based isolation layer welding quality.

[0033] Significantly improves production efficiency: The adoption of automatic welding process enables continuous and efficient welding, replacing the frequent adjustments and intermittent operations of traditional manual welding, and can increase production efficiency by more than 3 times.

[0034] Reduce the risk of subsequent processes: The optimized bevel design increases the thickness of the isolation layer, providing sufficient margin for the interpass cleaning and root cleaning operations of subsequent pipe welding, effectively avoiding rework and heat treatment caused by accidental damage to the isolation layer.

[0035] Significantly reduce manufacturing costs: By moving the RT flaw detection node forward to before the K-shaped isolation layer bevel processing, the flaw detection surface is simplified to a regular smooth plane. The flaw detection compensation block can be easily obtained by processing the remaining material from the opening, completely avoiding the high cost and high difficulty of processing irregular curved surface compensation blocks in the traditional process, and greatly reducing flaw detection costs and manufacturing difficulty.

[0036] Improved working environment: The automation of the welding process keeps operators away from welding arc light and fumes, effectively improving the working environment and protecting the occupational health of welders.

Claims

1. An automatic welding process for an isolation layer with an irregular bevel, characterized in that, Includes the following steps: S1: Open a pipe hole (4) on the shell (1). S2: Select an inner auxiliary cylinder (5) and an outer auxiliary cylinder (6). The inner diameter of the inner auxiliary cylinder (5), the inner diameter of the outer auxiliary cylinder (6), and the diameter of the connecting hole (4) are all the same. The outer auxiliary cylinder (6) is fixed to the outer wall of the shell (1), and the inner auxiliary cylinder (5) is fixed to the inner wall of the shell (1). Ensure that the inner auxiliary cylinder (5), the outer auxiliary cylinder (6), and the connecting hole (4) are coaxial, so that the inner wall of the inner auxiliary cylinder (5), the inner wall of the outer auxiliary cylinder (6), and the hole wall of the connecting hole (4) form a continuous and uninterrupted annular wall structure (7). S3: A nickel-based isolation layer (3) of uniform thickness is automatically deposited on the annular wall structure (7) using a welding torch. The isolation layer (3) covers the hole wall of the pipe hole (4) and extends to the inner wall of the inner auxiliary cylinder (5) and the inner wall of the outer auxiliary cylinder (6), respectively. S4: Remove the excess isolation layer (3) outside the inner auxiliary cylinder (5), outer auxiliary cylinder (6) and pipe hole (4) so ​​that the two end faces of the remaining isolation layer (3) are flush with the inner and outer side walls of the shell (1), respectively.

2. The automatic welding process for an irregular bevel isolation layer according to claim 1, characterized in that, In step S1, a pipe hole (4) is opened on the housing (1) by machining, and the remaining material of the opening is retained; In step S4, the remaining material from the opening is made into a flaw detection compensation block (9). The shape of the flaw detection compensation block (9) is adapted to the aperture of the isolation layer (3). The flaw detection compensation block (9) is placed in the opening area of ​​the isolation layer (3) for flaw detection.

3. The automatic welding process for an irregular bevel isolation layer according to claim 2, characterized in that, If the flaw detection is qualified, the isolation layer bevel (8) is processed on the remaining isolation layer (3). If the flaw detection is unqualified, the defect location is removed and then repaired by manual welding. After repair welding, the flaw detection is carried out again until the flaw detection is qualified.

4. The automatic welding process for an isolation layer with an irregular bevel according to any one of claims 3, characterized in that, The processed isolation layer bevel (8) is a K-shaped bevel.

5. An automatic welding process for an isolation layer with an irregular bevel according to any one of claims 1-4, characterized in that, In step S3, before welding, the housing (1) is installed on the welding positioner and the welding torch is placed inside the annular wall structure (7). During welding, the welding positioner is used to make the housing (1) together with the inner auxiliary cylinder (5) and the outer auxiliary cylinder (6) rotate synchronously and about the axis of rotation of the pipe hole (4). During the rotation, the welding torch moves along the axial direction of the pipe hole (4) to automatically build up the weld.

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