Aluminum alloy brazing sheet and method for producing same

Abstract

This aluminum alloy brazing sheet is an aluminum alloy brazing sheet in which a brazing material and a core material are laminated in this order, and the core material is formed from an aluminum alloy containing 0.50-2.00% by mass of Mn, 0.40-2.00% by mass of Mg, 1.50% by mass or less of Si, and 1.00% by mass or less of Fe, with the remainder being aluminum and unavoidable impurities. The brazing filler metal is formed from an aluminum alloy containing 4.00-13.00 mass% of Si, and further containing 2.00 mass% or less of Mn, 0.30 mass% or less of Ti, 0.30 mass% or less of Zr, and 0.30 mass% or less of Cr, with the remainder being aluminum and unavoidable impurities, and the core material has a crystal grain diameter of 20-300 [mu] m, and the brazing filler metal has a grain diameter of 20-300 [mu] m. The ratio alpha (alpha = Ka / Kb) of the flow coefficient Ka after the application of 5% deformation to the flow coefficient Kb before the application of deformation in a drooping flow test is 0.55 or more. The aluminum alloy brazing plate disclosed by the invention has excellent brazing property in flux-free brazing.

Description

technical field [0001] The present invention relates to an aluminum alloy brazing sheet used for brazing an aluminum material in an inert gas atmosphere or in a vacuum without using a flux. Background technique [0002] Brazing joining is widely used as a joining method for products having many fine joints, such as aluminum heat exchangers and mechanical members. In order to braze join aluminum materials (including aluminum alloy materials), it is necessary to destroy the oxide film covering the surface and bring molten brazing filler metal into contact with a base material or similar molten brazing filler metal. In order to destroy the oxide film of aluminum, there are generally methods of using flux and methods of heating in vacuum, and both of them have been put into practical use. [0003] Brazed joints are used in many fields. As the most representative product manufactured by brazing, there is an automotive heat exchanger. The vast majority of automotive heat exchan...

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Problems solved by technology

[0016] Furthermore, even if the amount of Mg in the core material is limited, when the grain size of the core material is small, there is a problem that during brazing, the diffusion of Si in the brazing filler metal to the core material becomes significant, causing the core The heat exchange cannot be maintained due to the melting of the core material, or sub-grains remaining in the brazing in the low-processed part when press processing, etc., and the diffusion of Si in the solder to the core material becomes significant The shape of the device

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