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A welding method for inner hole welding of tube and tube sheets of small-aperture heat exchange tubes

A welding method and technology of heat exchange tubes, applied in welding equipment, heat exchange equipment, arc welding equipment, etc., can solve the problem of thick welding torch tip, inapplicability of small-diameter heat exchange tubes and tube sheets, no nickel and nickel Alloy small-diameter tube tube sheet technology research results and other issues, to achieve the effect of improving safety

Active Publication Date: 2021-09-24
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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  • A welding method for inner hole welding of tube and tube sheets of small-aperture heat exchange tubes
  • A welding method for inner hole welding of tube and tube sheets of small-aperture heat exchange tubes
  • A welding method for inner hole welding of tube and tube sheets of small-aperture heat exchange tubes

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Experimental program
Comparison scheme
Effect test

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 application relates to welding technology, and discloses a method for welding the inner hole of a tube plate of a small-diameter heat exchange tube, which can effectively eliminate welding defects such as concaves on the outer surface of the joint and arc craters on the back. The inner diameter of the heat exchange tube is 9-15 mm, and the wall thickness is 1-2 mm; the method includes: adjusting the position of the tungsten needle of the welding torch head according to the tube sheet boss with grooves, so that when the welding torch is inserted and is in the position to be welded In the normal state, the tungsten needle is located on one side of the tube plate boss and at a position within 0 to 0.5 mm from the end face of the tube plate boss to be welded; the heat exchange tube and the tube plate boss are coaxially assembled Yes, and ensure that the gap between the end faces of the two pairs to be welded is within 0-0.1 mm; select any position between 3-5 o'clock and 7-9 o'clock as the arc starting point, and set the arc starting point Back uphill welding; divide the circle to be welded into 2N intervals according to the selected arc starting point, and set the current of each interval according to the recommended process parameters, and perform all-position inner hole welding on the circle 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 Patents(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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