BRAZING WIRE BRAZING METHOD

PROBLEM TO BE SOLVED: To improve the joining efficiency and to prevent the development of defective joining by using a heat resistant metal-made thin cored wire filling brazing filler metal in the inner part as a fin fixed material together with a brazing wire for heat exchanger. SOLUTION: The metallic wire is formed into the cored wire 4 having hollow cross section and the powdery brazing filling metal 5 is filled in the inner part to make the brazing wire 10. Then, the butting surface, i.e., the slit of the metallic wire formed at the time of forming the cored wire 4, is closed at the room temp. and is opened at a little by heating at the time of brazing, to enable the formation of a melt-out part 9 of the brazing filler metal 5. The brazing wires 10 are welded and tack-welded to a fin 1 with a suitable interval. At this time, the brazing filler metal melt-out part 9 is made to the retracting position by about 90 deg. from the tack-welded point to avoid the closing. The brazing filler metal 5 is melted at the brazing temp. by charging in a heating furnace and the molten brazing filler metal 7 is flowed onto the joining surface between the fin 1 and the cored wire 4, and joined.