| 摘要 |
PURPOSE: To abolish a hardening heat treatment by closely arranging a thick heat conduction block surrounding an aluminum tube at a part close to a position to be brazed and requiring a large hardness to prevent a deterioration of the hardness. CONSTITUTION: In achieving the brazing, a block 4 for heat conduction is closely provided on the periphery of the part required to keep the hardness as large as that of an aluminum tube 1. For example, when the copper block 4 for heat conduction whose heat conductivity is extremely larger than that of the aluminum tube 1 is used, the heat conducted through the aluminum tube 1 during the brazing and the radiation heat by a burner flame are rapidly absorbed and diffused to prevent the temperature of the aluminum tube 1 in the vicinity of the block 4 for heat conduction from being increased much. The hardness of the aluminum tube 1 is similar to that before the brazing, and the hardening heat treatment of the aluminum tube 1 can be dispensed with, resulting in the large economical effect. |
