| 摘要 |
PURPOSE:To prevent a microcrack from being generated due to reheating by executing the quenching at a specific cooling speed, at the time of brazing an Al alloy for generating an intermetallic compound whose melting point is lower than Al, as a base metal. CONSTITUTION:By using an Al-Cu alloy containing about 0.5% Cu, a heat exchanger use tube 1 is formed by extrusion forming, a fin 2 made of an Al alloy is brazed and an obtained heat exchanger is brazed, and thereafter, quenched at a cooling speed of >=10 deg.C/min from a supersaturated state that an intermetallic compound whose melting point is lower than Al, such as Cu-Al, Mg2Si, etc. is not deposited, to a room temperature. In case of reheating for the purpose of a repair of a brazing failure and a junction to other member, since the intermetallic compound whose melting point is lower than Al does not exist, such a defect as they are melted preferentially earlier than Al and a microcrack is generated is eliminated.
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