A method of manufacturing a welding groove on an outer end of a nozzle

Abstract

The application discloses a manufacturing method of a welding groove on an outer port of a connecting pipe, and the method steps are as follows: (1) a groove is processed on the outer end surface of the connecting pipe; (2) a transition layer is built up on the inner wall of the connecting pipe, the side wall and the bottom surface of the groove; (3) a surface layer is built up on the transition layer, and the material of the surface layer is the same as that of the outer pipeline; and (4) the outer port of the connecting pipe after the building up is subjected to turning processing, so that the outer diameter of the outer port of the connecting pipe is close to the outer diameter of the outer pipeline, and a welding groove is processed on the surface layer of the outer port end surface of the connecting pipe, so that the connecting pipe can be butt welded with the outer pipeline through the welding groove on the surface layer of the outer port. The manufacturing method of the welding groove on the outer port of the connecting pipe is simple in operation process, high in production efficiency, free of repeated turning, and capable of greatly reducing the risk of deformation of the connecting pipe after the building up and the turning.

Description

Technical Field

[0001] This invention relates to the field of pressure vessels made of composite steel plates, and specifically to a method for manufacturing a weld bevel on the outer port of a nozzle. Background Technology

[0002] The shell and nozzles of pressure vessels made of composite steel plates are typically made of carbon steel. A stainless steel corrosion-resistant layer or a stainless steel corrosion-resistant layer needs to be laminated onto the shell and nozzles. The external pipes connecting to the pressure vessel are usually made of stainless steel. When welding the external pipes to the nozzles on the pressure vessel, a bevel needs to be machined at the nozzle end to ensure full penetration. Since the weld overlay only covers the inner wall of the nozzle, the bevel is mostly made of carbon steel. Connecting it to the stainless steel external pipe inevitably presents the challenge of welding dissimilar steels. Currently, the common method to solve this problem is to manually weld a stainless steel layer onto the pre-machined bevel surface of the nozzle, then machine the bevel again before connecting it to the stainless steel external pipe. While this method theoretically solves the dissimilar steel welding problem, in practice it is cumbersome, requires repeated machining, has low efficiency, a high defect rate, and is difficult to inspect non-destructively. Furthermore, when welding stainless steel onto the machined nozzle bevel, the thinned areas are prone to deformation, especially the inner diameter, which shrinks significantly. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a manufacturing method for welding bevels on the outer port of a pipe that can improve work efficiency, welding qualification rate and dimensional accuracy.

[0004] To solve the above problems, the technical solution adopted by the present invention is: a method for manufacturing a weld bevel on the outer port of a connector, characterized by the following steps:

[0005] (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.

[0006] (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.

[0007] (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.

[0008] (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.

[0009] Furthermore, a method for manufacturing a weld bevel on the outer port of a connector, wherein s1 is 2-3 mm.

[0010] Furthermore, a method for manufacturing a weld bevel on the outer port of a connector, wherein s2 is 2-3 mm.

[0011] Furthermore, a method for manufacturing a weld bevel on the outer port of a connector, wherein: both the transition layer and the surface layer are stainless steel layers.

[0012] Furthermore, a method for manufacturing a weld bevel on the outer end of a connector, wherein: the outer diameter of the outer end of the connector is equal to the outer diameter of the external pipe, and 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.

[0013] The advantages of this invention are: the manufacturing method of welding bevel on the outer port of the pipe is simple to operate, has high production efficiency, does not require repeated turning, and the method of welding first and then turning can greatly reduce the risk of pipe deformation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the pipe fitting after the groove is processed according to the present invention.

[0015] Figure 2 This is a schematic diagram of the structure after the weld overlay transition layer of the pipe according to the present invention.

[0016] Figure 3 This is a schematic diagram of the structure after the weld overlay layer of the pipe according to the present invention.

[0017] Figure 4 This is a schematic diagram of the structure after the pipe is welded and the weld bevel is machined according to the present invention.

[0018] Figure 5 This is a schematic diagram of the connection between the welded beveled nozzle and the external pipeline as described in this invention. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0020] A method for manufacturing a weld bevel on the outer end of a connector, characterized by the following steps:

[0021] (1) such as Figure 1 As 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.

[0022] (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.

[0023] (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.

[0024] (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.

[0025] 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.

[0026] 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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