Manufacturing method for welding groove in outer port of connecting pipe

Abstract

The invention discloses a method for manufacturing a welding groove in an outer end opening of a connecting pipe. The method comprises the following steps that (1) a groove is machined in the outer end face of the connecting pipe; (2) overlaying transition layers on the inner wall of the connecting pipe and the side wall and the bottom surface of the groove; (3) surfacing a surface layer on the transition layer, wherein the material of the surface layer is the same as that of the external pipeline; and (4) turning the outer port of the connecting pipe after surfacing to enable the outer diameter of the outer port of the connecting pipe to be close to the outer diameter of the external pipeline, and machining a welding groove in the surface layer of the end surface of the outer port of the connecting pipe to enable the connecting pipe and the external pipeline to be subjected to same-material butt welding through the welding groove in the surface layer of the port. The manufacturing method for the welding groove in the outer port of the connecting pipe is simple and convenient in operation procedure and high in production efficiency, repeated turning is not needed, and the risk of deformation of the connecting pipe can be greatly reduced by turning after surfacing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pressure vessels made of composite steel plate, in particular to a manufacturing method of welding groove on external port of nozzle. BACKGROUND

[0002] The shell of pressure vessel made of composite steel plate and the nozzle on the shell usually adopt carbon steel base material, and a corrosion-resistant layer of stainless steel or a corrosion-resistant layer of stainless steel by surfacing is needed on the shell and the nozzle, and the external pipeline connected with the pressure vessel is usually made of stainless steel. When the external pipeline is connected with the nozzle of the pressure vessel by welding, the end of the nozzle needs to be machined to form a groove so that the nozzle can be fully penetrated. Since the nozzle is only surfaced on the inner wall, when the nozzle is machined to form a groove, most of the groove is made of carbon steel, and when the nozzle is connected with the external pipeline made of stainless steel, the problem of dissimilar steel welding must be solved. At present, in order to solve the problem of dissimilar steel welding, the common welding method is to manually surfacing a layer of stainless steel on the surface of the machined groove of the nozzle, then machining a groove again, and then connecting the nozzle with the external pipeline made of stainless steel. Although this method theoretically solves the problem of dissimilar steel welding, in actual operation, the steps are complicated, repeated turning is needed, the efficiency is low, the surfacing defect rate is high, nondestructive testing is difficult, and the surfacing stainless steel on the machined groove of the nozzle is prone to deformation, especially the inner diameter is obviously shrunk. SUMMARY

[0003] The present application aims to provide a manufacturing method of welding groove on external port of nozzle, which can improve the working efficiency and surfacing qualified rate, and has high size accuracy.

[0004] In order to solve the above problems, the technical scheme adopted by the present application is as follows: a manufacturing method of welding groove on external port of nozzle, characterized in that the method steps are as follows: (1) a circular truncated cone-shaped groove coaxial with the outer end face of the nozzle is machined on the outer end face of the nozzle, the bottom diameter of the groove is smaller than the port diameter of the groove, the angle of the groove port is α, α is 20-40 degrees, the outer diameter of the external pipeline to be connected with the nozzle is d (unit: mm), the bottom diameter of the groove is equal to d+4 mm, the depth T of the groove is t1*tanα+t2 / cosα+4 mm, t1 is the wall thickness of the external pipeline, t2 is the total thickness of the metal layer to be surfaced on the inner wall of the nozzle (unit: mm); (2) a transition layer is surfaced on the inner wall of the nozzle, the side wall and the bottom of the groove, and the thickness of the transition layer is s1; (3) a surface layer is surfaced on the transition layer, the material of the surface layer is the same as that of the external pipeline, the thickness of the surface layer on the inner wall of the nozzle is s2, the height of the surface layer in the groove is flush with the top surface of the groove, and t2=s1+s2; (4) Turning the outer port of the welding head after welding, so that the outer diameter of the outer port of the welding head is close to the outer diameter of the external pipeline, and a welding groove is processed on the surface layer of the outer port surface, so that the welding head can be butt welded with the external pipeline through the welding groove on the surface layer.

[0005] Further, a manufacturing method of a welding groove on an outer port of a welding head, wherein: s1 is 2-3mm.

[0006] Further, a manufacturing method of a welding groove on an outer port of a welding head, wherein: s2 is 2-3mm.

[0007] Further, a manufacturing method of a welding groove on an outer port of a welding head, wherein: the transition layer and the surface layer are both stainless steel layers.

[0008] Further, a manufacturing method of a welding groove on an outer port of a welding head, wherein: the outer diameter of the outer port of the welding head is equal to the outer diameter of the external pipeline, and the surface layer on the inner wall of the welding head is turned, so that the inner diameter of the welding head after welding is equal to the inner diameter of the external pipeline.

[0009] The advantages of the present application are: the manufacturing method of the welding groove on the outer port of the welding head is simple in operation process and high in production efficiency, without repeated turning, and the welding and then turning can greatly reduce the risk of deformation of the welding head. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The structure diagram of the welding head after the groove is processed according to the present application.

[0011] Figure 2 The structure diagram of the welding head after the transition layer is welded according to the present application.

[0012] Figure 3 The structure diagram of the welding head after the surface layer is welded according to the present application.

[0013] Figure 4 The structure diagram of the welding head after the welding groove is welded and turned according to the present application.

[0014] Figure 5 The structure diagram of the welding head after the welding groove is processed and the welding head is butt jointed with the external pipeline according to the present application. DETAILED DESCRIPTION

[0015] The present application will be further described in detail below in combination with specific embodiments and drawings.

[0016] A manufacturing method of a welding groove on an outer port of a welding head, characterized in that: the method steps are as follows: (1) As shown in Figure 1As shown, a frustum-shaped groove 2 coaxial with the outer end face of the connector 1 is machined. The bottom diameter of the groove 2 is smaller than the port diameter of the groove 2. The angle of the port of the groove 2 is α, which is 20 to 40 degrees. In this embodiment, α is 30 degrees. The outer diameter of the external pipe 5 that the connector 1 needs to connect to is d, in mm. The bottom diameter of the groove 2 is equal to d + 4 mm. The depth T of the groove 2 is t1*tanα + t2 / cosα + 4 mm. t1 is the wall thickness of the external pipe, and t2 is the total thickness of the metal layer that needs to be welded on the inner wall of the connector, in mm. (2) such as Figure 2 As shown, a transition layer 3 is welded onto the inner wall of the connector 1, the side wall of the groove 2, and the bottom surface, and the thickness of the transition layer 3 is s1. (3) such as Figure 3 As shown, a surface layer 4 is welded onto the transition layer 3. The material of the surface layer 4 is the same as that of the external pipe 5. The thickness of the surface layer 4 on the inner wall of the pipe 1 is s2. The height of the surface layer 4 in the groove 2 is flush with the top surface of the groove 2. t2=s1+s2. (4) such as Figure 4 , Figure 5 As shown, the outer port of the welded connector 1 is machined so that the outer diameter of the outer port of the connector 1 is close to the outer diameter of the external pipe 5. A welding bevel 6 is machined on the surface layer of the outer port of the connector 1 so that the connector 1 can be butt welded to the external pipe 5 of the same material through the welding bevel 6 on the port surface layer 4.

[0017] In this embodiment, s1 is 2-3 mm; s2 is 2-3 mm. Both the transition layer 3 and the surface layer 4 are stainless steel layers, but they are made of different grades of stainless steel.

[0018] To achieve better connection, the outer diameter of the outer port of the connector 1 is equal to the outer diameter of the outer pipe 5. The surface layer 4 on the inner wall of the connector 1 is machined so that the inner diameter of the connector 1 after welding is equal to the inner diameter of the outer pipe 5.

Claims

1. A method for manufacturing a weld bevel on the outer end of a connector, characterized in that: The steps are as follows: (1) A frustum-shaped groove coaxial with the outer end face of the connector is machined. The bottom diameter of the groove is smaller than the port diameter of the groove. The angle of the port of the groove is α, which is 20 to 40 degrees. The outer diameter of the external pipe to be connected to the connector is d, in mm. The bottom diameter of the groove is equal to d+4mm. The depth T of the groove is t1*tanα+t2 / cosα+4mm. t1 is the wall thickness of the external pipe, and t2 is the total thickness of the metal layer to be welded on the inner wall of the connector, in mm. (2) A transition layer is welded on the inner wall of the pipe, the side wall of the groove and the bottom surface, and the thickness of the transition layer is s1. (3) A layer is welded on the transition layer. The material of the layer is the same as that of the external pipe. The thickness of the layer on the inner wall of the pipe is s2. The height of the layer in the groove is flush with the top surface of the groove. t2=s1+s2. (4) The outer end of the welded pipe is machined so that the outer diameter of the outer end of the pipe is close to that of the outer pipe. A welding bevel is machined on the surface of the outer end of the pipe so that the pipe can be butt welded to the outer pipe of the same material through the welding bevel on the surface of the port.

2. The manufacturing method of the welding bevel on the outer port of the pipe according to claim 1, characterized in that: s1 is 2-3 mm.

3. The manufacturing method of the welding bevel on the outer port of the pipe according to claim 1, characterized in that: s2 is 2-3 mm.

4. The manufacturing method of the welding bevel on the outer port of the pipe according to claim 1, characterized in that: Both the transition layer and the surface layer are made of stainless steel.

5. The manufacturing method of the welding bevel on the outer port of the pipe according to claim 1, characterized in that: The outer diameter of the connector at the outer port is equal to the outer diameter of the external pipe. The surface layer on the inner wall of the connector is machined so that the inner diameter of the connector after welding is equal to the inner diameter of the external pipe.

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