| 摘要 |
PROBLEM TO BE SOLVED: To provide a smooth punching press working method for a superhigh-hardness steel plate, capable of producing a high-quality punched article hardly generating delayed fracture with high productivity.SOLUTION: A smooth punching press working method includes a first process of punching a hole for shaving on a superhigh-hardness steel plate to produce a bole material 21 for shaving, and a second process of shaving the hole of the hole material for shaving using a finish blanking mold 11A. The clearance of a punch and a die in the first process is controlled to be 5 to 7% of the thickness of the steel plate, and a punch making the cutting edge of the punch round is used as a punch 15A of the finish blanking mold in the second process. A finished product 22 having a hole 23 with smooth cut area is produced by performing a first shaving work making the machining allowance of shaving as a dimension in which a smooth surface is obtained without broken face exposure, and a second shaving work changing the punch and making the machining allowance δ as a minute dimension for finishing smaller than the first machining allowance δ. |
