To improve the deep drawability and ridging resistance of a steel sheet by subjecting a steel in which a content of C is low and contents of Si, Mn, P, S, Al and N are specified to cold rolling-annealing and specifying a value of a concentrating degree in the orientation within a colony of the steel sheet.
A compsn. of a steel is composed of, by weight, ≤0.01% C, ≤2.0% S, ≤3.0% Mn, ≤0.15% P, ≤0.05% S, 0.01 to 0.20% Al, ≤0.01% N, and the balance Fe with inevitable impurities. This steel is heated, is soaked, is rolled, is coiled, is thereafter subjected to cold rolling and is successively subjected to recrystallization annealing. In this way, the value of the concentrating degree within the colony of the steel sheet S=(30°-X)/30° is regulated to ≤0.6. In the formula, X denotes the average difference in the orientation among the boundaries within the colony. The colony denotes the group of the crystal grains in which the difference in the orientation between the adjacent crystal grains is regulated to ≤30°. In addition to the fundamental components of this steel, one or two kinds among 0.001 to 0.2% Ti and 0.001 to 0.2% Nb or, furthermore, 0.0001 to 0.008% B are incorporated according to necessary.
MORITA MASAHIKO
FURUKIMI OSAMU
