Patent ID: 8628631

Claim:
A method for producing a ferritic stainless steel sheet having an average r-value of 2.5 or more characterized by using a casting having, in mass %, 0.001 to 0.010% C, 0.01 to 0.30% Si, 0.01 to 0.30% Mn, 0.01 to 0.04% P, 0.0010 to 0.0100% S, 10 to 20% Cr, 0.001 to 0.020% N, 0.05 to 0.30% Ti, and 0.0002 to 0.0050% Mg, with a balance consisting of Fe and unavoidable impurities, and the value of Σ defined by the expression <1> of 0.70 or less, Σ=0.9Si+8.6P+2Ti+0.5Mn−0.5 <1>, and the average composition of the Mg containing oxides dispersing in said casting satisfies the expressions <2> and <3>, 17.4(Al 2 O 3 )+3.9(MgO)+0.3(MgAl 2 O 4 )+18.7(CaO)≦500 <2>, (Al 2 O 3 )+(MgO)+(MgAl 2 O 4 )+(CaO)≧95 <3>, wherein the chemical components in the parentheses mean mol % of the relevant chemical components, respectively; and the method comprises hot rolling the casting to a steel sheet; thereafter cold rolling the hot-rolled steel sheet, without subjecting to hot band annealing, at a reduction ratio of 30% or more in a rolling mill equipped with rolls 300 mm or larger in diameter; and, thereafter, subjecting said cold-rolled steel sheet to intermediate annealing at a heating temperature T4 in the range defined by the expression <7>, cold rolling said annealed steel sheet again to a prescribed thickness and, thereafter, subjecting the cold-rolled steel sheet to final annealing at a heating temperature T5 in the range defined by the expression <8>, 700 ≦T 4(° C.)≦−50−5,457/(log([Ti]×[C])−2.6) <7>, −100−5,457/(log([Ti]×[C])−2.6)≦ T 5(° C.)≦−5,457/(log([Ti]×[C])−2.6) <8>.