Method for producing aluminum alloy heat exchanger

Abstract

A method for producing an aluminum alloy heat exchanger includes applying a coating material prepared by mixing an Si powder, a flux powder, and a binder to a surface of a multiport flat refrigerant tube, assembling an aluminum alloy bare fin with the multiport flat refrigerant tube, and brazing the multiport flat refrigerant tube and the aluminum alloy bare fin to obtain an aluminum alloy heat exchanger, the multiport flat refrigerant tube being formed of an aluminum alloy extruded material that includes 0.5 to 1.7 mass % of Mn, less than 0.10 mass % of Si, and less than 0.10 mass % of Cu, with the balance being Al and unavoidable impurities, the aluminum alloy bare fin being a corrugated fin that is obtained by forming an Al—Mn—Zn alloy material, the coating material being prepared by mixing an Si powder, a Zn-containing compound flux powder, a Zn-free compound flux powder, and a binder, the Si powder being applied in an amount of 1 to 4 g/m, and the aluminum alloy heat exchanger obtained by brazing having a configuration in which a deep area of the refrigerant tube has the highest potential, and the potential decreases in order from a surface area of the refrigerant tube, a fin joint fillet, and the fin.