Pipe plate inner hole welding method for small-aperture heat exchange pipe

A welding method and heat exchange tube technology, which are applied in welding equipment, arc welding equipment, heat exchange equipment, etc., can solve the problem that the connection between the small aperture heat exchange tube and the tube sheet is not suitable, the torch head is thick, and there is no nickel and nickel. Alloy small-aperture tube tube sheet technology research results and other issues, to achieve the effect of eliminating welding defects and eliminating arc craters

Active Publication Date: 2020-04-21
SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Existing literature and data show that the inner hole welding technology is rarely used in the field of nuclear energy. It is mainly used in the manufacture of evaporators and heat exchangers in the chemical industry. Wire inner hole welding is not suitable for the connection of small-diameter heat exchange tubes and tube sheets; and there are no technological research results suitable for the inner hole welding of nickel and nickel alloy small-diameter tube-tube sheets for reference

Method used

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  • Pipe plate inner hole welding method for small-aperture heat exchange pipe
  • Pipe plate inner hole welding method for small-aperture heat exchange pipe
  • Pipe plate inner hole welding method for small-aperture heat exchange pipe

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Embodiment 1

[0077] This embodiment 1 is the inner hole welding of pipe A and pipe B.

[0078] Both pipe A and pipe B are made of UNS N10003 nickel-based alloy pipes, with an outer diameter of 13.72mm and a wall thickness of 1.65mm; the weight percentage of alloy chemical composition: 70.8Ni, 6.96Cr, 16.7Mo, 4.2Fe, 0.35Si, 0.053C, 0.001S, 0.002P, 0.002B, 0.71Mn, 0.014Al, 0.011Ti, others≤0.5.

[0079] Step 1: Preparation before welding

[0080] Clean the ends of pipe A and pipe B to be welded with an organic solvent such as alcohol, acetone, etc., to remove the burrs on the end faces, and ensure that the end faces to be welded are flat.

[0081] Process 2: Tungsten needle positioning

[0082] Adjust the position of the tungsten needle of the torch head according to the pipe A with the groove, so that when the welding torch is inserted and in the ready-to-weld state, the tungsten needle is located on the side of the pipe A and the distance from the end face of the pipe A to be welded is wi...

Embodiment 2

[0103] In this embodiment, the inner holes of the tube sheet and the heat exchange tube are welded.

[0104] The type of material used is the same as in Example 1, which is still UNS N10003 alloy. Considering that the tube sheet has a strong ability to transfer and absorb welding heat, the welding process is slightly adjusted.

[0105] Among them, embodiment 2 is the same as the method of process 1 to process 5 of embodiment 1, and the arc starting parameters and arc terminating parameters of embodiment 2 and process 6 of embodiment 1 are the same, and the difference between embodiment 2 and embodiment 1 lies in: different intervals in the welding process The current parameter settings of the positions are different, as shown in Table 5.

[0106] Table 5 Current parameters of different interval positions in the welding process

[0107] interval Peak current A Ratio of base value% 1 stage 60 45 2 stages 58 45 3 stages 56 45 4 stages 55...

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Abstract

The invention relates to a welding technology, discloses a pipe plate inner hole welding method for a small-aperture heat exchange pipe, and can effectively eliminate the welding defects that the outer surface of a joint is concave inwards and arc extinguishing pits are formed in the back surface of the joint. The inner hole diameter of the heat exchange pipe is 9-15 mm, and the wall thickness is1-2 mm. The method comprises the steps that the position of the tungsten pin of a welding gun head is adjusted according to a pipe plate boss with a groove so that when the welding gun is inserted andis in a to-be-welded state, the tungsten pin is located on one side of the pipe plate boss and the distance between the tungsten pin and the to-be-welded end face of the pipe plate boss is within 0-0.5 mm; the heat exchange pipe and the pipe plate boss are coaxially assembled, and it is ensured that the gap between the to-be-welded end faces of the two assemblies is within 0-0.1 mm; any one of the positions of 3-5 o'clock and 7-9 o'clock is selected as an arcing point, and uphill welding is set after arcing; and the circumference to be welded is equally divided into 2N sections according to the selected arcing points, the current of each section is set according to the recommended process parameters and all-position inner hole welding is performed on the circumference to be welded.

Description

technical field [0001] The application relates to welding technology, in particular to the welding method and technology of inner hole welding of pipe tube sheet. Background technique [0002] In order to meet the application requirements of energy scenarios such as space reactors and marine reactors, in addition to the inherent safety, economy, and high efficiency requirements, miniaturization, light weight, and modularization have become the future fourth-generation nuclear energy represented by molten salt reactors. The main development trend, which places high demands on reactor structural materials and manufacturing processes. Expansion joint sealing welding is currently the main manufacturing method for tube sheets of heat exchange equipment such as nuclear energy evaporators and heat exchangers. This method is mature and simple, but its tube-tube-sheet joint has low strength, large stress concentration coefficient, and poor fatigue resistance. The tube-sheet thicknes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K9/167B23K9/028B23K9/235B23K101/14
CPCB23K9/0026B23K9/0282B23K9/167B23K9/235B23K2101/14
Inventor 陈双建董生孔巧玲李志军
Owner SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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