| 摘要 |
PURPOSE: A method for manufacturing a steel molded body facilitates controlling a heating temperature for molding the molded body and prevents the oxidation or annealing of heated blank materials being transferred to a mold. CONSTITUTION: A method for manufacturing a steel molded body includes the following steps: a step of forming a blank material (140) with cutting a steel sheet coil; a step of directly loading the non-heated blank material on a lower mold (140) of which the upper side has an electrode; a step of allowing the front side of the blank material loaded on the lower mold to function as a resistance; and a step of pressing and molding the blank material heated at a temperature of 680 to 980°C using an upper mold, and then cooling the blank material for 3 to 4 seconds in order to maintain the molded condition of the blank material and in order to secure the desired hardness of the blank material. The steel sheet coil comprises 0.1 to 0.4 wt% of C, below 0.5 wt% of Si, below 0.1 wt% of N, 0.01 to 0.1 wt% of Al, below 0.05 wt% of P, 0.8 to 2 wt% of Mn, 0.002 to 0.01 wt% of B, 0.1 to 0.5 wt% of Mo, 0.1 to 0.5 wt% of Cr, and remnants Fe and other inevitable impurities. The steel sheet coil has a molding temperature of 680 to 980°C. |
