Aluminum alloy brazing sheet and brazing method

Abstract

The purpose of the invention of the present application is to provide an aluminum alloy brazing sheet able to achieve excellent brazing properties by effectively weakening an oxide film on a brazing surface. This aluminum alloy brazing sheet is obtained by cladding a brazing material, which contains 6-13% of Si, with the remainder consisting of Al and unavoidable impurities, on one or both surfaces of an aluminum alloy core material and is used to braze aluminum in an inert gas atmosphere or in a vacuum, wherein the aluminum alloy brazing sheet is characterized in that cladding is effected by interposing a plate-like material between the core material and the brazing material, the plate-like material containing one or more elements selected from among 0.05% or more of Li, 0.05% or more of Be, 0.05% or more of Ba, 0.05% or more of Ca and 0.4% or more of Mg, with the remainder consisting of Al and unavoidable impurities.

Description

technical field [0001] The present invention relates to an aluminum alloy brazing sheet for brazing aluminum in an inert gas atmosphere or in a vacuum and a brazing method using the aluminum alloy brazing sheet. Background technique [0002] Brazing joining is widely used as a joining method of aluminum products having a large number of thin joining parts, such as aluminum heat exchangers and machine parts. When brazing and joining aluminum (including aluminum alloys), it is necessary to destroy the oxide film covering the surface, and to contact the molten brazing filler metal with the base material or similarly melted brazing filler metal. In order to destroy the oxide film, Generally, there are a method of using flux and a method of heating in a vacuum, and both are put into practical use. [0003] Brazing joints can be applied in various fields, but the most representative application area is heat exchangers for automobiles. Most of the heat exchangers for automobiles ...

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Problems solved by technology

[0009] However, in the cladding material, the core material and the sacrificial anode material have their respective roles. When the amount of Mg added increases, the erosion caused by the molten brazing filler metal occurs excessively or adversely affects the corrosion resistance. In addition, Mg When the amount of addition is limited, the destructive effect of the oxide film on the surface of the brazing material is lacking

On the other hand, when it is desired to add Li, Be, Ba, and Ca to the core material and sacrificial anode material, the addition amount is further limited compared to Mg, so it is difficult to expect the effect of destroying the oxide film expected in the above proposal.

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