Aluminum alloy brazing sheet, and method for producing heat exchanger made from aluminum alloy

Abstract

An aluminum alloy brazing sheet which can be used for brazing in an inert gas atmosphere without using any flux, said aluminum alloy brazing sheet being characterized by comprising an aluminum alloy core material and an aluminum alloy brazing material, wherein one surface or both surfaces of the aluminum alloy core material is / are cladded with the aluminum alloy brazing material, the aluminum alloy core material contains 0.8 to 1.8% by mass of Mn, 0.05 to 0.20% by mass of Mg and a remainder made up by aluminum and unavoidable impurities, the aluminum alloy brazing material contains 6 to 13% bymass of Si and a remainder made up by aluminum and unavoidable impurities, the thickness of the brazing sheet is 0.12 mm or less, and the thickness of the brazing material is 0.012 mm or less. According to the present invention, an aluminum alloy brazing sheet for fluxless brazing use can be provided, which does not undergo the problem of the buckling deformation of a tip part of a fin or the problem of a defect in the formation of a fillet during brazing by heating despite the sheet thickness of as small as 0.12 mm or less of the brazing sheet.

Description

technical field [0001] The present invention relates to an aluminum alloy brazing sheet used for brazing of aluminum or an aluminum alloy in an inert gas atmosphere without using a flux, and an aluminum alloy heat exchanger using the brazing sheet Manufacturing method. Background technique [0002] For aluminum heat exchangers (mainly automotive heat exchangers) having many small joints, brazing is often used as the joining method. In order to join aluminum by brazing, it is necessary to destroy the oxide film covering the surface of the brazing filler metal, and bring the molten brazing filler metal into contact with the base material or similarly molten brazing filler metal. [0003] To destroy the oxide film, a flux is generally used. The method of coating a fluoride-based flux and brazing in an inert gas atmosphere such as nitrogen is used in aluminum brazing represented by automotive heat exchangers. It is widely used in the joining of products. In recent years, howe...

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Problems solved by technology

Although the Mg added to the core material will diffuse into the solder layer during the brazing heating process, it will reduce the oxide film to form a spinel-type oxide (Al 2 MgO 4 ) to weaken the oxide film, but if the time point when Mg reaches the surface of the solder is delayed or the amount of Mg arriving is small, the weakening of the oxide film cannot be sufficiently carried out, so that ideal brazing properties cannot be obtained

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