| 摘要 |
PURPOSE:To enhance the wear resistance, strength and toughness of dies made of Cr steel having a specified composition for cold forging by carburizing the dies in a vacuum. CONSTITUTION:Dies used in cold forging are manufactrured with a low alloy steel having a composition contg. 0.50-0.70% C, <1.5% Si, <1.5% Mn, <1.5% Ni, 5.0-9.0% Cr, 0.2-5.0% Mo and 0.5-1.5% V or further contg. 0.5-5.0% W and/or <2.0% Co. The dies are heated in an evacuated furnace while feeding a carburizing gas such as gaseous propane to form gas carburized layers on the die surfaces. Gaseous nitrogen is then introduced, and the dies are hardened in a cooled chamber and tempered. |
