A method of welding a plug-in connection to a thick-walled housing

Abstract

The application discloses a method for assembling and welding a plug-in pipe with a thick-wall shell, which comprises the following steps: S1, cutting the thick-wall shell to obtain an opening and a bevel; S2, welding a backing plate under the inner surface of the thick-wall shell and at the edge of the opening through spot welding; S3, welding four clamping blocks on the outer wall of the plug-in pipe through spot welding, then vertically placing the plug-in pipe with the four clamping blocks on the backing plate in the opening, so that the longitudinal axis of the plug-in pipe overlaps with the longitudinal axis of the opening; S4, welding a right-angle weld close to the root of the plug-in pipe through shielded metal arc welding, then polishing the welding points of the clamping blocks and the plug-in pipe by using a grinder and removing the clamping blocks; and S5, welding in the bevel to weld the plug-in pipe with the thick-wall shell together, and after the welding is completed, removing the backing plate from the inner surface of the thick-wall shell through carbon arc gouging. The method improves the opening, assembling and welding efficiency, and guarantees the welding quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure vessel manufacturing, in particular to a method for assembling and welding an inserted nozzle with a thick-walled shell. BACKGROUND

[0002] Nozzles on the shell of a pressure vessel generally have three types of insertion, embedding and placement, among which the application of the inserted nozzle is the most widely used. The groove form of the inserted nozzle and the shell is generally single-sided V-shaped, single-sided U-shaped or K-shaped, but for the shell thickness greater than 50mm, the groove form of the pipe hole is generally single-sided U-shaped or K-shaped. The machining difficulty of single-sided U-shaped groove is large, and fixed machine tools such as boring and milling machines need to be used for machining. The back of the K-shaped groove has a large amount of root cleaning work and a large amount of weld metal filling. If the groove angle on both sides is adjusted to be small, although it will reduce a part of the weld material filling amount, the depth of the back root cleaning will be deep, and the root defects are difficult to clean completely, and the K-shaped groove form needs to be gas cut twice, which is low in efficiency. The present application reduces the weld metal filling amount of the inserted nozzle and the thick-walled shell, improves the opening, assembling and welding efficiency, and ensures the welding quality. SUMMARY

[0003] In view of the above technical problems, the present application provides a method for assembling and welding an inserted nozzle with a thick-walled shell, characterized in that the method comprises the following steps: S1, cutting the thick-walled shell to obtain an opening and a groove; S2, welding a backing plate below the inner surface of the thick-walled shell and at the edge of the opening by spot welding; S3, welding four clamping blocks on the outer wall of the inserted nozzle by spot welding, then vertically placing the inserted nozzle with the four clamping blocks on the backing plate in the opening, so that the longitudinal axis of the inserted nozzle overlaps with the longitudinal axis of the opening; S4, welding the right-angle weld close to the root of the inserted nozzle by using stick arc welding, then polishing the welding points of the clamping blocks and the inserted nozzle using a grinder and removing the clamping blocks; and S5, welding in the groove to weld the inserted nozzle and the thick-walled shell together, and after the welding is completed, using a carbon arc air gouging to gouge the backing plate from the inner surface of the thick-walled shell.

[0004] In a preferred embodiment, the surface of the opening and the groove in S1 is polished smooth and exposed to metal luster using the grinder.

[0005] In a preferred embodiment, the opening and the groove in S1 are cut into shape at one time using a saddle type automatic cutting machine.

[0006] In a preferred embodiment, the groove is a single-sided V-shaped outer groove.

[0007] In a preferred embodiment, the spot welds in S3 are higher than the outer surface of the thick-walled shell.

[0008] In a preferred embodiment, the shape of the clamping blocks is a right trapezoid.

[0009] In a preferred embodiment, the four clamping blocks are evenly arranged around the plug-in connector.

[0010] In a preferred embodiment, the spot weld flash remaining on the surface of the plug-in connector is polished in S4.

[0011] In a preferred embodiment, the bevel is welded in S5 by using a saddle submerged arc automatic welding or a stick arc welding.

[0012] In a preferred embodiment, S5 further comprises: after the skimming of the backing plate, the position where the backing plate is skinned is polished by using a grinder.

[0013] Compared with the prior art, the present disclosure has the beneficial effects of: reducing the weld metal filling amount of the plug-in connector and the thick-walled shell, improving the opening, assembling and welding efficiency, and ensuring the welding quality. BRIEF DESCRIPTION OF DRAWINGS

[0014] The novel features of the application are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present application will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the application are utilized, and the accompanying drawings of which:

[0015] Figure 1 A flow chart of a method of assembling a plug-in connector and a thick-walled shell according to an exemplary embodiment of the present disclosure is shown;

[0016] Figure 2 A schematic view of a plug-in connector and a thick-walled shell according to an exemplary embodiment of the present disclosure is shown; and

[0017] Figure 3 A schematic view of a part of a plug-in connector and a thick-walled shell according to an exemplary embodiment of the present disclosure is shown in more detail.

[0018] Reference Signs: 1, plug-in connector, 2, thick-walled shell, 3, backing plate, 4, clamping block. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms without being limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Nothing in the following detailed description is intended to imply any particular component, feature or step is essential to the application. Those skilled in the art will understand that various features or steps can be substituted or combined with one another without departing from the scope of the present disclosure.

[0020] Figure 1 A flow chart of a method of welding a spool to a thick-walled shell is shown, according to an exemplary embodiment of the present disclosure. The present disclosure proposes a method of welding a spool 1 to a thick-walled shell 2, which can include S1-S5. Specifically, the method can include S1. At S1, the thick-walled shell 2 can be cut to obtain an opening and a bevel. In preferred embodiments, the surfaces of the opening and the bevel can be polished smooth and reveal a metallic luster using the grinder. In preferred embodiments, the opening and the bevel can be cut in one step using a saddle-type automatic cutting machine. In other embodiments, the opening and the bevel can be formed by other means using other tools deemed appropriate by those skilled in the art. Preferably, the bevel is a single-V type external bevel. In other embodiments, the bevel can be a single-V type internal bevel, a double-V type external bevel, a single-U type internal bevel, a single-U type external bevel, a double-U type internal bevel, a double-U type external bevel, a single-Y type internal bevel, a single-Y type external bevel, a double-Y type internal bevel, a double-Y type external bevel, a single-K type internal bevel, a single-K type external bevel, a double-K type internal bevel, a double-K type external bevel, or other types of bevels deemed appropriate by those skilled in the art. The method can further include S2. At S2, a backing plate 3 can be welded below the inner surface of the thick-walled shell 2 and at the edge of the opening by spot welding. In preferred embodiments, the backing plate 3 can be circular. In preferred embodiments, the thickness of the circular backing plate 3 can be 6-8 mm, the width of the circular backing plate 3 can be 30-35 mm, and the backing plate 3 can be in the form of split pieces, and the backing plate 3 can be overlapped with the thick-walled shell 2 by a width of 5-6 mm. Figure 2A schematic view of the spigot 1 and the thick-walled shell 2 according to an exemplary embodiment of the present disclosure is shown. The method can further comprise S3. At S3, four clamping blocks 4 can be welded to the outer wall of the spigot 1 by spot welding, and then the spigot 1 with the four clamping blocks 4 is vertically placed on the base plate 3 in the opening, so that the longitudinal axis of the spigot 1 overlaps with the longitudinal axis of the opening, thereby ensuring the assembly accuracy of the spigot 1 and the thick-walled shell 2 and improving the assembly efficiency. In a preferred embodiment, the four clamping blocks 4 can be uniformly arranged around the spigot 1. Preferably, the shape of the clamping block 4 can be a right trapezoid. In other embodiments, the shape of the clamping block 4 can be a rectangle, a triangle, or other shapes deemed appropriate by those skilled in the art. Figure 3A schematic view of a partial (node I) of the plug-in connector 1 and the thick-walled shell 2 according to the exemplary embodiment of the present disclosure is shown in more detail. In the preferred embodiment, the spot welds can be higher than the outer surface of the thick-walled shell 2. The thickness δ of the thick-walled shell 2 can be greater than or equal to 50 mm and less than or equal to 100 mm or greater than or equal to 100 mm and less than or equal to 150 mm, etc. The external weld width between the plug-in connector 1 and the thick-walled shell 2 can be 26-30 mm (for the case where the thickness δ is greater than or equal to 50 mm and less than or equal to 100 mm) or 32-38 mm (for the case where the thickness δ is greater than or equal to 100 mm and less than or equal to 150 mm) or other width as deemed appropriate by those skilled in the art. The weld width of the internal root between the plug-in connector 1 and the thick-walled shell 2 can be set to 15-18 mm (for the case of the saddle type submerged arc automatic welding) and 5-6 mm (for the case of the shielded metal arc welding) or other width as deemed appropriate by those skilled in the art, according to different welding methods. The root gap according to the technical solution of the present disclosure can ensure the minimum gap of the root welding, the upper gap width is set to make the overall gap deep and narrow, the overall welding filling amount can reach the minimum, and the welding workload is reduced. The method can further comprise S4. In S4, the right-angle weld near the root of the plug-in connector 1 can be welded by shielded metal arc welding, and then the spot weld between the clamp block 4 and the plug-in connector 1 is polished by a grinder and the clamp block 4 is removed. In the preferred embodiment, the spot weld scar remaining on the surface of the plug-in connector 1 can be polished smooth. The method can further comprise S5. In S5, welding can be performed in the gap to weld the plug-in connector 1 and the thick-walled shell 2 together, and after the welding is completed, the backing plate 3 is planed off from the inner surface of the thick-walled shell 2 by a carbon arc air gouging. In the preferred embodiment, the gap can be welded by saddle submerged arc automatic welding or shielded metal arc welding to weld the plug-in connector 1 and the thick-walled shell 2 together. In the preferred embodiment, S5 can further comprise that after the backing plate 3 is planed off, the position where the backing plate 3 is planed off can be polished by a grinder to enable smooth transition with the periphery of the position. In addition, the position which is locally lower than the surface of the shell 2 can be repaired by shielded metal arc welding. The technical solution of the present disclosure greatly reduces the workload of root cleaning and welding.

[0021] Compared with the prior art, the technical solution of the present disclosure reduces the weld metal filling amount of the plug-in connector and the thick-walled shell, improves the opening, assembling and welding efficiency, ensures the welding quality, and greatly reduces the workload of root cleaning and welding.

[0022] It should be understood that the systems and / or methods described in the embodiments provided herein can be combined, modified or sub-divided into new embodiments, without creative skill. These embodiments should also be included within the scope of the present application.

[0023] A large number of specific examples are provided in the embodiments provided herein, it should be understood that these examples are merely intended to provide a detailed description of the embodiments of the present application and not to limit the present application. The embodiments of the present application can be practiced without these specific examples. In some embodiments, methods, structures and / or techniques well known to those skilled in the art are not described in detail in order not to obscure the understanding of the present application.

[0024] Although the preferred embodiments of the present application have been shown and described herein, it should be understood by those skilled in the art that these embodiments are provided only by way of example. Various changes, modifications and alternatives will now occur to those skilled in the art without departing from the present application. It should be understood that various alternatives to the embodiments of the present application described herein are optionally used to practice the present application. It is intended to define the scope of the present application by the claims and it is intended to cover all methods and structures falling within the scope of these claims and their equivalents.

Claims

1. A method of welding a plug-in connection to a thick-walled shell, characterized in that The method comprises the following steps: S1, cutting the thick-walled shell to obtain an opening and a groove, the groove being a single-side V-shaped outer groove; S2, welding a backing plate under the inner surface of the thick-walled shell and at the edge of the opening by spot welding; S3, welding four clamping blocks to the outer wall of the plug-in connector by spot welding, then vertically placing the plug-in connector with the four clamping blocks on the backing plate in the opening, so that the longitudinal axis of the plug-in connector overlaps with the longitudinal axis of the opening, wherein the shape of the clamping block is a right trapezoid; S4, welding a right-angle weld close to the root of the plug-in connector by using stick arc welding, then grinding the welding points of the clamping block and the plug-in connector using a grinder and removing the clamping block; and S5, welding the plug-in connector and the thick-walled shell together in the groove, after the welding is completed, using a carbon arc air gouging to gouge the backing plate from the inner surface of the thick-walled shell.

2. The method of claim 1, wherein, In S1, the surface of the opening and the groove is polished smooth using the grinder and exposed to a metallic luster.

3. The method of claim 1, wherein, In S1, the opening and the groove are cut into shape at one time using a saddle-shaped automatic cutting machine.

4. The method of claim 1, wherein, In S3, the welding points of the spot welding are higher than the outer surface of the thick-walled shell.

5. The method of claim 1, wherein, The four clamping blocks are evenly arranged around the plug-in connector.

6. The method of claim 1, wherein, In S4, the spot welding scars remaining on the surface of the plug-in connector are polished smooth.

7. The method of claim 1, wherein, In S5, the groove is welded using a saddle submerged arc automatic welding or stick arc welding.

8. The method of claim 1, wherein, S5 further comprises: after gouging the backing plate, polishing the position where the backing plate is gouged using the grinder.

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