| 摘要 |
PROBLEM TO BE SOLVED: To give corrective process to a slab made of a material hard to mold such as austenitic heat resisting steel and to prevent fogging or bite in a cold forging process subsequent to the corrective process. SOLUTION: The die assembly in which the upper insert 4 and the lower insert 5 are arranged separately inside a reinforcing ring 2 and a molding cavity 7 is formed to range from the upper insert 4 to the lower insert 5 and a punch 6 is inserted from the top in the forming cavity 7 and a knockout pin 10 is inserted from below in the forming cavity 7 and the flat surface of the upper end of the knockout pin 10 constitutes a part of the bottom surface of the cavity 7.
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