Aluminum welding ring and flux core in use for welding joint of tubes made from aluminum and aluminum alloy, and preparation method

Abstract

A flux cored aluminium ring for the butt connection between two aluminium or Al-alloy tubers by soldering is composed of the shell made of Al-Si alloy foil and the core made of Al-Si alloy wire and alloy powder. Said Al-Si alloy foil (or wire) contains Al (86.5-97 Wt %), Si (3-13), Sr (0.01-0.3) and La (0.01-0.2). Said alloy powder consists of KalF4-K3AlF6 eutectic and Si powder. Its preparing steps are smelting Al-Si alloy ingot, preparing Al-Si alloy band and wire, preparing their foil and wire, grinding alloy powder, making core wire, and making flux cored ring.

Description

technical field

[0001] The invention relates to a solder used for brazing aluminum and aluminum alloy pipe joints. Background technique

[0002] In the past ten years, with the rapid development of the automobile, air-conditioning, and refrigeration industries, aluminum refrigeration accessories, especially the brazing of aluminum alloy pipe joints and connectors, have been more and more widely used. The brazing of aluminum alloys usually uses aluminum-silicon alloy solders. Since there is a dense oxide film on the surface of the aluminum alloy, flux must be added during brazing. At present, flux is added manually when brazing aluminum alloy pipe joints, and too much or uneven addition of flux often occurs. On the one hand, it causes waste of brazing flux; on the other hand, too much residue is difficult to clean. When the acid mixture is used to soak and remove the residue after brazing, it often leads to corrosion of aluminum products, and the joints soaked in acid often ...

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