스테인리스 강판(SUS420)의 냉간단조용 금형개발에 관한 연구

A Study on the Development of Cold Forging Dies for Stainless Steel Sheet (SUS420)

Cold forging die for metal scissor is made by electric discharge machine. The impression of female die is made by electric discharge machine, the heat treatment is applied, and the impression is polished. When we forge goods by using this kind of die, the abrasion is severe and the crack occurs after forging about 240 strokes. Because the die should be frequently produced in the case, the cost rises, the work is delayed, and the precesion of goods is not good. Therefore, the electric discharge machine was not used in this study. Main die was produced by making hob, installing the hob to cold hobbing press, indenting the die material, and cold hobbing the impression. The die life was increased to 5,000-6,000 strokes in this case. In the future study, the die life will be increased to 10,000 strokes by changing the following : (1) the pre-treatment of slug, (2) the structure of die block, (3) the heat treatment of die material