MANUFACTURE OF COLD FORGED PRODUCT

摘要

PURPOSE:To manufacture a cold forged product efficiently at low cost by preliminarily forming a hot rolled steel material containing a specific amount of C at specific temperature, performing air coolig or gradual cooling after holding it under specific conditions, and then carrying out cold forging without spheroidizing. CONSTITUTION:A hot rolled steel material or drawn steel material containing 0.13-1.50% C is formed preliminarily by hot work at 500 deg.C-Ac3 when 0.13- 0.765% C is contained, or at 500 deg.C-Acc when 0.765-1.50% C, thus manufacturing a preliminarily formed product. This product is held for 1-60min at 600 deg.C-Ac3 in the former case, or at 600 deg.C-Acc in the latter case, obtaining a spheroidized structure in an extremely short time. This is air-cooled or gradually cooled and cold forging is carried out to improve production efficiency greatly while reducing manufacturing cost.