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. 0.0060W0.0250% C, ≤0.03% Si, 0.06W 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. WAc3 point.
YAMADA TERUAKI
UEDA SHIGERU
FUJII HIROMU
IWATA KENJI
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