Brazing sheet formed of aluminum alloy

Abstract

Provided is a brazing sheet formed of an aluminum alloy, which exhibits excellent strength after brazing, excellent corrosion resistance and excellent brazability even if the thickness thereof is less than 200 [miu]. A brazing sheet formed of an aluminum alloy, which is provided with a core material, a brazing material that is arranged on one surface of the core material and is formed of an Al-Si-based alloy, and a sacrificial material that is arranged on the other surface of the core material, and which has a thickness less than 200 [miu]. This brazing sheet formed of an aluminum alloy is characterized in that: the core material contains more than 1.5% by mass but 2.5% by mass or less of Cu and 0.5 to 2.0% by mass of Mn with the balance made up of Al and unavoidable impurities; the sacrificial material contains 2.0 to 7.0% by mass of Zn and more than 0.10% by mass but 3.0% by mass or less of Mg with the balance made up of Al and unavoidable impurities; the brazing material and the sacrificial material respectively have a thickness of 15 to 50 [miu]; and the total of the cladding ratios of the brazing material and the sacrificial material is 50% or less.

Description

technical field [0001] The present invention relates to an aluminum alloy brazing sheet suitable for use in heat exchangers for automobiles and the like. Background technique [0002] Conventionally, as a material for heat exchangers such as automobiles, a brazing sheet composed of an aluminum alloy (hereinafter also referred to as Al alloy) provided with a brazing material and a sacrificial material on both sides of a core material has been used. [0003] In recent years, heat exchangers for automobiles tend to be more lightweight and downsized. Along with this, it is desired to reduce the thickness of brazing sheets constituting tubes that account for most of the mass of the heat exchanger. Up to now, the thickness of the brazing sheet has been reduced to about 200 μm, but in order to further reduce the thickness, it is necessary to achieve high strength and high corrosion resistance to match the thinning. However, if the core material is thinned along with thickness redu...

AI Technical Summary

Problems solved by technology

[0010] However, in Patent Document 1 and Patent Document 2, the thickness of the brazing sheet disclosed in the examples is at least 250 μm. In order to obtain a thin-walled brazing sheet with a thickness of less than 200 μm, it is necessary to achieve both strength after brazing and In addition to corrosion resistance and brazeability, there is room for further improvement

[0011] In the case of a thin-walled material with a plate thickness of less than 200 μm, it can be seen that the thickness of the core part that bears the strength becomes thinner, so after brazing heating, the residual amount of various additive elements is greatly reduced, and the strength is greatly reduced.

In particular, the reduction of the remaining amount of Cu added to increase the potential of the core material has a great influence, and it has been confirmed that the corrosion resistance is also reduced in addition to the strength.

Images