| 摘要 |
PURPOSE:To produce a high strength cold-rolled steel plate of superior deep drawability and working embrittleness resistance by subjecting a steel contg. C, Si, Mn, P, S, Al and Ti in a specific ratio to hot rolling, cold rolling and continuous annealing under specific conditions. CONSTITUTION:A steel consisting of <0.015% C, <0.2% Si, 0.6-1.8% Mn, <0.010% P, <0.010% S, 0.01-0.10% Al, 0.03-0.30% Ti, and >4 Ti/C and the balance Fe and unavoildable impurities is made into a slab. This is heated to below 1200 deg.C, after which it is hot-rolled at finish temps. above the Ar3 transformation point and is coiled at >=620 deg.C temps. Thence, after pickling, it is subjected to cold rolling at >=65% drafts followed by continuous annealing at a 750-880 deg.C temp. range. Thereby, the high strength cold-rolled steel plate of 35-45kg/mm.<2> tensile strength, about >=1.7 r value, high ductility, non-aging, and superior paintability and working embrittleness resistance is produced stably. |
