Patent ID: 9581398
Date: 2017-02-28
CPC Classifications: B22F,B23K,B32B,C21C,C22C,F28D,F28F

Claim:
1. A heat exchanger comprising heat exchange tubes formed of aluminum, and fins formed of aluminum and brazed to the heat exchange tubes, wherein each heat exchange tube is formed of an alloy which contains Mn in an amount of 0.2 to 0.3 mass %, Cu in an amount of 0.1 mass % or less, Fe in an amount of 0.2 mass % or less, and Si in an amount of 0.2 mass % or less, the balance being Al and unavoidable impurities; a Zn diffused layer is formed in an outer surface layer portion of the heat exchange tube; conditions of T≦200, 0.57≦A≦1.5, D/T≦0.55, and 0.0055≦A/D≦0.025 are satisfied, where T is a thickness [μm] of a peripheral wall of the heat exchange tube, A is a Zn concentration [mass %] at an outermost surface of the outer surface layer portion of the heat exchange tube, and D is a maximum depth [μm] of the Zn diffused layer; and a spontaneous potential of the Zn diffused layer is lower than a spontaneous potential of an inner portion of the peripheral wall of the heat exchange tube, the inner portion being located on the inner side of the Zn diffused layer.