Abstract: A martensitic stainless steel sheet has a steel composition including: by mass %, 0.30 to 0.60% of C; 0.05 to 1.00% of Si; 0.10 to 1.50% of Mn; 11.0 to 15.0% of Cr; 0.01 to 0.60% or less of Ni; 0.01 to 0.50% of Cu; 0.01 to 1.0% of Mo; 0.01 to 0.50% of V; 0.03% or less of Al; 0.01 to 0.05% of N; 0.01% or less of O.

Abstract: The stainless steel contains 0.0001 mass % or more and 0.15 mass % or less of C, 0.30 mass % or more and 2.0 mass % or less of Si, 0.1 mass % or more and 15 mass % or less of Mn, 5 mass % or more and 30 mass % or less of Ni, 0.0001 mass % or more and 0.01 mass % or less of S, 16 mass % or more and 25 mass % or less of Cr, 0 mass % or more and 5 mass % or less of Mo, 0 mass % or more and 0.005 mass % or less of Al, 0 mass % or more and 0.0010 mass % or less of Mg, 0.0010 mass % or more and 0.0060 mass % or less of 0, and 0.0001 mass % or more and 0.5 mass % or less of N, and at least includes an inclusion with an equivalent circle diameter of 5 ?m or more, having the average composition of 5 mass % or more of MnO, 20 mass % or more of Cr2O3+Al2O3, 1 mass % or more of Al2O3, and 5 mass % or less of Ca0. The number density of the inclusion having the composition is 0.5 inclusions/mm2 or less.

Abstract: A ferritic stainless steel with chemical composition includes, in mass %, Cr: 10.5 to 25.0%; Al: 0.01 to 0.20%; Ti: 0.15% to 0.35%; O: 0.0001 to 0.0030%; and Mg: 0.008×[% Al] or more, in which oxysulfide-containing inclusions are present in the steel, a number ratio of the oxysulfide-containing inclusions whose minor axis is 3 ?m or more is 5 pieces/mm2 or less, and a number ratio of the oxysulfide-containing inclusions whose minor axis is 15 ?m or more is 0.05 pieces/mm2 or less. 75% or more of the inclusions whose minor axis is 3 ?m or more have an oxysulfide part whose composition satisfies formulae (1) and (2), CaO+Al2O3+MgO?90%??formula (1), Al2O3/MgO?1.25??formula (2).

Abstract: The stainless steel for metal foils includes, in mass %, 0.0001% or more and 0.15% or less of C, 0.30% or more and 2.0% or less of Si, 0.1% or more and 15% or less of Mn, 0.040% or less of P, 5% or more and 30% or less of Ni, 0.0001% or more and 0.01% or less of S, 16% or more and 25% or less of Cr, 5% or less of Mo, 0.005% or less of Al, 0.0030% or less of Ca, 0.0010% or less of Mg, 0.0010% or more and 0.0060% or less of O, and 0.0001% or more and 0.5% or less of N. The number of inclusions with a maximum equivalent circle diameter of 5 ?m or more is 0.5 inclusions/mm2 or less in a thickness of 0.010 mm or more and 0.2 mm or less.