| 摘要 |
PURPOSE: A tube insertion hole of a heat exchange header pipe and a punch for manufacturing the same are provided to form a filler metal for brazing in the linear portion and the both round portions of a tube insertion hole. CONSTITUTION: A punch for manufacturing a tube insertion hole of a heat exchange header pipe comprises a cutting part(21), a molding part(22), and a gradient part(23). The cutting part is formed under a punch(20). The cutting part is blade shape and works a tube insertion hole by cutting a header pipe. The molding part is formed to be inclined and forms rake face for tube insertion guide on the upper round part of the tube insertion hole. The gradient part is formed in the both sides of the cutting part and forms burring on the round portion of the tube insertion hole. The degree of the gradient part is 10 to 50°.
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