Production manner null of the containing Ti non-ageing properties cold rolling steel sheet whose defect of nonmetallic inclusion origination

摘要

PURPOSE:To produce a Ti-containing non-ageing cold rolled steel plate having few defects caused by non-metallic inclusion by executing continuous casting and rolling to the specific composition of molten steel composed of C, Si, Mn, S, P, Ti, specific oxides and Fe after deoxidizing. CONSTITUTION:The deoxidation is executed to the unoxidized molten steel adding the specific quantities of Mn-containing material and Ti-containing material and the molten steel composed of 0.02% C, 0.03-0.30% Si, 0.03-1.5% Mn, 0.0001-0.150% S, 0.001-0.100% P, 0.02-0.15% Ti and if necessary, further 0.0002-0.0025% B and/or 0.005-0.025% Nb and the balance of Fe and the inevitable impurities, and containing 16-92% MnO in low m.p. liquids oxide, in which the main components are MnO-Ti oxide, as the non-metallic inclusion composition, is obtd. This molten steel is continuously cast. Hot rolling, cold rolling and annealing are executed to the obtd. cast slab as the ordinary process. By this method, the Ti-containing non-ageing cold rolled steel plate having excellent material characteristic of workability, etc., without depositing the oxide in a continuous casting nozzle and any defect caused by large shaped non-metallic inclusion, is obtd.