| 摘要 |
PROBLEM TO BE SOLVED: To provide a die-casting product in which even in the case blow hole exists in the inner part of the die-casting product, sufficient strength can be held in a female screw part and the fastening strength with the female screw can be improved. SOLUTION: A hole 30 is preliminarily formed at a female screw forming position by die casting. After die casting, machining process is applied to the hole 30 to prepare the hole to the suitable size for tapping, and the cast surface is left on at least a part of the inner peripheral portion 3a on the inner peripheral surface in the prepared hole 31 after machining, and the tapping is applied to the prepared hole 31 while leaving the cast surface portion 5 as it is to form the female screw 3. COPYRIGHT: (C)2004,JPO
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