| 摘要 |
PROBLEM TO BE SOLVED: To stabilize a brazing property and brazing strength of a heat transfer fin by winding a corrugated plate in the direction of a corrugation to form an annular heat transfer fin, bringing the heat transfer fin into contact with a tube wall of a heat exchanger and arranging it and forming a groove which holds a brazing filler metal in the outside of the apex of the corrugation of the heat transfer fin which comes into contact with the tube wall. SOLUTION: A steel strip is formed into a corrugated plate having a prescribed pitch with a press, and a brazing filler metal holding groove 29 is simultaneously formed in the apex 27 of a corrugation which is formed in a flat plate part capable of coming into surface contact with a tube wall. The corrugated plate is bent into an annular shape to form a heat transfer fin 30. The depth of the brazing filler metal holding groove 29 is specified to 0.2-0.8 mm, preferably 0.3-0.5 mm. A paste-like brazing filler metal is filled in the brazing filler metal holding groove 29 or a bar-like brazing filler metal is fit into the groove, the heat transfer fin 30 is inserted into a heat exchanger tube body 28, brazing is executed by being passed through a heating furnace for brazing, and a heat exchanger is formed. The thickness of the corrugated plate is specified to 0.01-0.8 mm, preferably 0.05-0.5 mm. The pitch of the corrugation is preferably specified to 2-6 mm.
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