| 摘要 |
PROBLEM TO BE SOLVED: To improve the erosion resistance of a fin material to a molten brazing filler metal and to prevent deterioration in pressure-resisting strength by constituting an Al alloy fin of an Al alloy in which the grain size of crystalline grains in the plane perpendicular to the thickness direction of a fin material and also the ratio between the length of crystalline grains in a rolling direction and that in a direction perpendicular to it are specified, respectively. SOLUTION: The Al alloy fin for heat exchanger is constituted of an Al alloy where average grain size of crystalline grains in the plane perpendicular to the thickness direction of a fin material is as large as 200-50000μm and which is composed of roundish crystalline grains in which the ratio of the length LT of crystalline grains in a direction perpendicular to the rolling direction of the fin material to the length L of crystalline grains in the rolling direction, LT/L is regulated to 0.1-1. It is preferanble that this Al alloy has a composition consisting of >1.5-3% Fe and the balance Al with inevitable impurities and, if necessary, further containing one or more kinds from among 0.1-0.5% Mn, 0.1-0.5% Si, and 0.05-0.7% Cu and further containing 0.5-3% Zn and 0.05-0.2% Zr and further 0.05-0.2% Mg. The above crystal structure is formed by controlling cold rolling of the fin material.
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