| 摘要 |
PURPOSE:To produce the titled material having excellent super mirror-finish workability by executing a specific triple melting treatment to the steel contg. specific ratios of C, Si, Mn, Ni, Mo, Cr and Cu and specifying the contents of nonmetallic inclusions and hardness of the material. CONSTITUTION:The triple refining of electric furnace melting, electro-slag remelting and consumable electrode vacuum melting is executed to the material having the compsn. contg., by weight, 0.30-0.80% C, <=1% Si, <=1% Mn, <=1% Ni, <=1% Mo, 6.0-15.0% Cr, <=1% Cu and the balance Fe with inevitable impurities. In this way, the upper limit of the nonmetallic inclusions involved in the material is regulated, by areal percentage, to 0.015% and is permitted to use at >=45 HRC hardness, by which the mold material for injection molding of plastics having excellent super mirror-finish workability is obtd. |
