| 摘要 |
PURPOSE:To produce a cold-rolled steel sheet having excellent deep drawability by subjecting a continuously cast billet composed of a low-carbon steel contg. a specific amt. of Ti to continuous hot rolling and further to cold rolling to form a sheet material and annealing continuously said material under specific temp. conditions. CONSTITUTION:A moldten steel contg. 0.0060-0.0250% C, <=0.03% Si, 0.06- 0.50% Mn, <=0.035% P, <=0.035% S, >=0.001% solAl, <=0.0045% N and Ti in such a way as to satisfy the formula ( I ) in relation with the content of N and adjusted to <=90ppm free oxygen content is continuously cast. Reflux is generated in the molten steel if necessary by applying electromagnetic flow to the molten steel in a continuous casting mold to prevent thickening of elements on the solidified surface. Such continuously cast billet is subjected to continuous hot rolling to form a sheet material which is pickled and descaled then the material is cold- rolled to a sheet material having an intended thickness. The sheet material is subjected to continuous annealing including soaking in the temp. range of the recrystallization temp. -Ac3 point. |
