Patent ID: 9440315
Filing Date: 2016-09-13
CPC Classification: B21D,B23K,C22C,F28D,F28F

Claim Text:
1. An aluminum alloy heat exchanger comprising a coated aluminum alloy extruded refrigerant tube having an aluminum alloy bare fin made of an Al—Mn—Zn alloy and brazed thereto, the aluminum alloy extruded refrigerant tube comprising 0.6-1.7 mass % of Mn, less than 0.05 mass % of Cu, less than 0.10 mass % Si and the balance being Al and unavoidable impurities, the coating on the aluminum alloy extruded refrigerant tube comprising a mixture of Si powder, a Zn-containing compound flux powder and a binder, a mixing ratio of the Si powder to the Zn-containing compound flux powder being 10:90-40:60, the binder being present in an amount of 5-40% based on the total amount of the coating, the coating being present on an outer surface of the refrigerant tube such that the total amount of Si powder and Zn-containing compound flux powder is 5-30 g/m2, the refrigerant tube having a surface and an area underlying the diffusion depth of Si and Zn, wherein the surface of the refrigerant tube subjected to brazing has a potential lower than the area of the refrigerant tube that is underlying the diffusion depth of Si and Zn by 20-200 mV, both the fin and the area of the refrigerant tube subjected to brazing having a potential, the potential of the fin being lower than the potential of the area of the refrigerant tube underlying the depth of Si and Zn.