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Method for brazing copper aluminum tubes without aid of brazing flux

A brazing method and flux-free technology, which is applied to tubular items, welding equipment, welding/welding/cutting items, etc., can solve the problem of short fusion line of copper-aluminum pipe welded joints, low welding success rate, and inapplicability to ultra-long pipes Non-straight pipe joint welding and other problems, to achieve the effect of automatic welding, short welding time, improvement of air tightness and bonding strength

Inactive Publication Date: 2012-07-18
李明雨 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, through further research, it has been found that the copper-aluminum pipe welded joint prepared by the method of the invention has shortcomings such as short fusion line and low welding success rate, and this method is not suitable for welding super-long pipes and non-straight pipe joints.

Method used

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  • Method for brazing copper aluminum tubes without aid of brazing flux
  • Method for brazing copper aluminum tubes without aid of brazing flux
  • Method for brazing copper aluminum tubes without aid of brazing flux

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] see figure 1, Take one T2 copper tube 1 and one 1060 aluminum tube 2. The dimensions of the copper tube and the aluminum tube are both: the tube wall thickness is 0.5mm, the tube length is 80mm, and the outer diameter is 8mm. After flattening the nozzles of the copper and aluminum pipes, the nozzle of one end of the copper pipe 1 is expanded into a socket by thermal expansion method. 11 has a depth of 10 mm and an inner diameter of 8.2 mm. Take a piece of Zn-4Al brazing filler metal alloy sheet (melting point is 380°C), punch out a brazing filler metal thin tube 3 with a thickness of 0.1 mm, an inner diameter of 8 mm, and a length of 12 mm through a punching machine. Clean the mouth of the aluminum tube 2 to be welded, the socket of the copper tube 1 and the brazing material thin tube 3 through an ultrasonic cleaning machine and dry them, and then insert the brazing material thin tube 3 into the socket straight tube part 11 of the copper tube 1 socket Insert the end o...

Embodiment 2

[0043] see figure 2 Compared with Example 1, this embodiment is different in that when the brazing preset joint is installed in the fixture, the copper tube 1 is put into the limiting fixture 5, and the limiting fixture 5 makes the copper tube 1 only move along its axis direction. Sliding (that is, axial sliding), the aluminum tube 2 is clamped by the fixing fixture 4; welding pressure and ultrasonic vibration are applied from the other end of the copper tube 1 along the tube axis through the ultrasonic horn 7, other steps, methods and embodiments 1 is the same.

[0044] The microscopic analysis of the longitudinal section of the welded copper and aluminum pipe joints shows that the average length of the welding fusion line reaches 10mm, that is, the overlapped parts of the copper and aluminum pipes in the socket are all welded; the weld structure is dense and the structure is distributed Uniform, without obvious pores and inclusions; the average thickness of the IMC layer o...

Embodiment 3

[0046] see image 3 Compared with Embodiment 1, this embodiment is different in that the welding pressure is applied axially at the end of the aluminum tube 2 through the pressure device 8, and the ultrasonic vibration is applied from the side wall of the aluminum tube 2 by the ultrasonic horn 7, and other Step method is identical with embodiment 1.

[0047] The specific implementation process is: after the joint temperature reaches 420°C, apply a constant welding pressure on the end of the aluminum tube 2 through the pressure device 8, and the pressure is 3 MPa; after the pressure is stable, start the ultrasonic pressure device to make the ultrasonic horn 7 Apply a contact pressure of 0.5MPa to the wall of the aluminum tube 2, and then start the ultrasonic vibration, the vibration direction is perpendicular to the axial direction of the aluminum tube, the ultrasonic vibration frequency is 30kHz, the amplitude is 20μm, and the vibration time is 5 seconds; stop the induction he...

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Abstract

The invention discloses a method for brazing copper aluminum tubes without the aid of brazing flux. The method includes the steps: firstly, expanding one end of optional one of the copper aluminum tubes into a socket by a thermal expansion method, manufacturing a brazing alloy plate into a brazing thin tube by a stamping method, and placing the brazing thin tube into the socket; secondly, inserting one end of another welded tube into the brazing thin tube, and tightly abutting the end opening of the welded tube to the bottom of the socket to form close fit; and thirdly, assembling the brazing thin tube and the welded tube on a welding fixture, performing local induction heating for joints, and applying proper welding pressure and ultrasonic vibration. The method can be used for brazing the thin-wall copper aluminum tubes without the brazing flux, fusion lines are long, welding seams are compact, slag inclusion is avoided, the air tightness and the bonding strength of the joints are greatly improved, reliability is high, welding time is short, and great production and use values are achieved.

Description

technical field [0001] The invention relates to a brazing method between metal materials, in particular to a flux-free brazing method between copper and aluminum tubes. Background technique [0002] The connection technology of copper and aluminum pipes is widely used in the refrigeration industry. The use of aluminum tubes instead of copper tubes as the main material of the internal pipes, connecting pipes, and circulation system pipes of the heat exchanger can not only reduce the weight of the equipment, but also greatly reduce the product cost. Because of this, the development of thin-wall copper-aluminum tube connection technology has always been a hot spot in the refrigeration industry. [0003] The technical indicators of copper-aluminum pipe joints include: joint strength, corrosion resistance and air tightness, and the factors that affect these technical indicators mainly include: the length of the fusion line of the joint, the internal stress of the joint, the cont...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K1/06B23K1/20B23K101/06B23K103/18
CPCB23K1/0008B23K1/20B23K1/002B23K1/19B23K1/06B23K2203/12B23K2203/10B23K2103/10B23K2103/12B23K1/18
Inventor 李明雨肖勇马鑫
Owner 李明雨
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