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Dissimilar metal connection method for copper-aluminum pipe

A connection method and technology of dissimilar metals, applied in metal processing equipment, welding equipment, high-frequency current welding equipment, etc., can solve the problems of reducing the mechanical properties of the weld, expensive cesium fluoroaluminate flux, and increasing manufacturing costs. Achieve the effects of improving air tightness and fatigue resistance, good controllability of heating temperature, and low heating peak temperature

Inactive Publication Date: 2011-08-17
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But there is following unstable quality problem in this method: 1) process window during welding is narrow
2) The welding seam cannot form obvious wetting fillets, which is prone to stress concentration and reduces the mechanical properties of the weld seam (especially the bending resistance performance)
However, the long-term reliability of the joint is still unknown (mainly related to the corrosion resistance of the joint), and the cesium fluoroaluminate flux is expensive, which increases the manufacturing cost

Method used

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  • Dissimilar metal connection method for copper-aluminum pipe
  • Dissimilar metal connection method for copper-aluminum pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A copper-aluminum pipe dissimilar metal connection method, such as figure 1 as shown,

[0019] 1) Use copper pipe 1 and aluminum pipe 2 each with an outer diameter of Φ10mm and a wall thickness of 0.8mm, and expand on the surface to be connected of the copper pipe, so that the inner diameter of the expanded part 3 is Φ10mm, take a positive tolerance, and expand The depth is 8mm (that is, the lap length). The outer diameter of the aluminum tube takes a negative tolerance.

[0020] 2) Immerse the surface to be connected of the copper tube 1 into trimethyl borate liquid flux, and coat the surface to be connected (outer surface) of the aluminum tube 2 with potassium fluoroaluminate paste flux. Then insert the aluminum pipe 2 in the copper pipe 1.

[0021] 3) Put the assembled joint into the inductor 4 for heating. When the potassium fluoroaluminate flux melts (560°C, controlled by a temperature controller), apply an axial pressure (6MPa) and maintain it for 1s, then rel...

Embodiment 2

[0024] A copper-aluminum pipe dissimilar metal connection method, such as figure 1 as shown,

[0025] 1) Use a section of copper tube 1 and aluminum tube 2 with an outer diameter of Φ30mm and a wall thickness of 1.2mm, and expand on the surface to be connected of the copper tube, so that the inner diameter of the expanded part 3 is Φ30mm, take a positive tolerance, and expand The depth is 15mm (that is, the lap length). The outer diameter of the aluminum tube takes a negative tolerance.

[0026] 2) Immerse the surface to be connected of the copper tube 1 into trimethyl borate liquid flux, and coat the surface to be connected (outer surface) of the aluminum tube 2 with potassium fluoroaluminate paste flux. Then insert the aluminum pipe 2 in the copper pipe 1.

[0027] 3) Put the assembled joint into the inductor 4 for heating. When the potassium fluoroaluminate flux melts (560°C, controlled by a temperature controller), apply an axial pressure (8MPa) and maintain it for 2s,...

Embodiment 3

[0030] A copper-aluminum pipe dissimilar metal connection method, such as figure 1 as shown,

[0031] 1) Use copper tube 1 and aluminum tube 2 each with an outer diameter of Φ60mm and a wall thickness of 3.0mm, and expand on the surface to be connected of the copper tube 1, so that the inner diameter of the flared part 3 is Φ60mm, take a positive tolerance, expand The mouth depth is 25mm (that is, the lap length). The outer diameter of the aluminum tube takes a negative tolerance.

[0032] 2) Immerse the surface to be connected of the copper tube 1 into trimethyl borate liquid flux, and coat the surface to be connected (outer surface) of the aluminum tube 2 with potassium fluoroaluminate paste flux. Then insert the aluminum pipe 2 in the copper pipe 1.

[0033] 3) Put the assembled joint into the inductor 4 for heating. When the potassium fluoroaluminate flux melts (560°C, controlled by a temperature controller), apply axial pressure (9MPa) and maintain it for 3s, then rel...

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Abstract

The invention discloses a dissimilar metal connection method for a copper-aluminum pipe, comprising the following steps of: (1) firstly dipping the part to be connected of a copper pipe with a liquid brazing agent, coating paste non-corrosive brazing agent at the part to be connected of an aluminum pipe, and then inserting the aluminum pipe into the copper pipe so as to be butted into a joint to be welded; and (2) putting the butted joint to be welded into an inductor of a high-frequency power supply, heating the workpieces by using a high-frequency power supply; when a potassium aluminum fluoride brazing agent is melted, applying axial pressure immediately and maintaining the pressure; and after a wet round angle is formed on the end surface of the copper pipe, cutting off the power supply, and then finishing the connection. The obtained butted joint does not contain any oxidized slag and has high strength and high compactness, and the butting length of the joint can be randomly adjusted in a large range.

Description

technical field [0001] The invention belongs to the field of welding technology, and relates to a connection method of dissimilar metals, in particular to a connection method of copper-aluminum pipe dissimilar metals. Background technique [0002] Due to the excessive use of non-renewable resources, the price of copper and its copper alloys continues to rise, which greatly increases the manufacturing cost of manufacturers. In order to rationally allocate non-renewable resources and save raw material costs, it is required in many industrial fields to reduce manufacturing costs by substituting aluminum for copper. However, copper and its alloys can provide good air tightness and electrical conductivity when mechanically pressed, while aluminum and its alloys are easy to oxidize and deform, resulting in reduced air tightness and electrical conductivity. Therefore, in order to meet the technical requirements of replacing copper with aluminum, the connection of copper-aluminum d...

Claims

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Application Information

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IPC IPC(8): B23K13/01
Inventor 卫国强
Owner SOUTH CHINA UNIV OF TECH
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