PURPOSE: To join a pipe well without deforming a fin by providing a Zn film with the specified thickness on the surface of at least one surface of the pipe and header of a heat exchanger, sticking the Al-Si alloy brazing filler having a limited diameter to the joining part of a fin bending part, pipe and header and executing a heating brazing.
CONSTITUTION: An Al made extruded porous pipe 1 and a plate 2 for a header are assembled and an Al made fin 3 is inserted between the extruded porous pipes 1. A Zn film in 1-50g/m2 thickness is provided on the surface of the plate 2 for header and extruded porous pipe 1 by a wet type plating treatment, flame spraying method or powder coating method in advance. Also, the Al-Si alloy brazing filler in 10-200μm grain size is applied by using the binder composed of an acrylic resin in advance among the bending part of the fin 3, extruded porous pipe 1 and plate 2 for header. Thereafter, a heating brazing is executed under a gaseous nitrogen atmosphere.
KUDO HAJIME
SAITO HITOSHI
