PURPOSE: To produce a cold-rolled steel sheet having excellent press formability with low-temp. coiling by subjecting a continuous casting hot billet of an aluminum killed steel having the specific compsn. contg. C, Mn, S, Al, and N and consisting of the balance Fe to heating and rolling under specific conditions.
CONSTITUTION: An aluminum killed steel contg. ≤0.04% C, 0.10W0.35% Mn, ≤0.015% S, ≤0.040% Al and ≤0.0030% N with 5W20 Al/N and consisting of the balance Fe and inevitable impurity elements is continuously cast and the resulted hot billet is subjected to temp. drop to ≥800°C and the Ar3 point or above to accelerate precipitation of AlN and MnS. The billet is then heated to 1,000W1,150°C and held for 40W100min to maintain the uniform temp. thereof. The heated billet is hot-rolled at the finishing temp. of the Ar3 point or above and a low coiling temp. of 550W650°C and is further subjected to cold rolling and continuous annealing, by which the cold-rolled steel plate having excellent press formability is obtd.
TAKAHASHI MASASHI
JPS5852439A | 1983-03-28 | |||
JPS5959831A | 1984-04-05 | |||
JPS59116327A | 1984-07-05 |