| 摘要 |
PURPOSE:To improve the hardness and blanking property of steel plates by subjecting a slab of steel contg. prescribed contents of C, Si, Mn, P, S, Al, N, etc. to heat treatment and machining under prescribed conditions. CONSTITUTION:The steel contg. 0.03-0.1% C, <=2% Si, 0.2-2% Mn, <=0.15% P, <=0.05% S, <=0.1% Al and <=0.08% N, or further contg. >=0.7 B/N and/or 0.1-1% Cr in addition to the above is melted. The slab of said steel is hot- rolled and cold-rolled to a prescribed thickness. The steel plate is heated and quickly cooled to Ac1 transformation point - Ac3 transformation point temp. to mixed transformation structure. Such plate is subjected to skin pass rolling at 2.5-15% draft. |
