Ferritic stainless steel casting and sheet and method for producing the same

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(Al2O3)+3.9(MgO)+0.3(MgAl2O4)+18.7(CaO)≦500 <2>,
• (Al2O3)+(MgO)+(MgAl2O4)+(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≦T4(° C.)≦−50−5,457/(log([Ti]×[C])−2.6) <7>,
• −100−5,457/(log([Ti]×[C])−2.6)≦T5(° C.)≦−5,457/(log([Ti]×[C])−2.6) <8>.