Abstract: A martensite-based stainless steel material has a composition containing: 0.30 to 0.60% by mass of C; 0.05 to 1.00% by mass of Si; 0.05 to 1.50% by mass of Mn; 0.040% by mass or less of P; 0.030% by mass or less of S; 13.0 to 18.0% by mass of Cr; 0.01 to 0.30% by mass of Ni; 0.01 to 1.00% by mass of Mo; 0.030% by mass or less of Al; 0.010 to 0.350% by mass of N; 0.0001 to 0.0030% by mass of Ca; and 0.001 to 0.010% by mass of O; 2.5 C+N being 1.10% or more, and the balance being Fe and impurities. The martensite-based stainless steel material has an average grain diameter of carbides of 0.50 ?m or less. Also, the number of the carbides having a size of 10 ?m or more is 0.20/cm2 or less.

Abstract: A ferritic stainless steel sheet includes a base metal and a nitrided layer that is formed on a surface of the base metal, a chemical composition of the base metal contains, in mass %, C: 0.001 to 0.020%, Si: 0.01 to 1.50%, Mn: 0.01 to 1.50%, P: 0.010 to 0.050%, S: 0.0001 to 0.010%, Cr: 16.0 to 25.0%, N: 0.001 to 0.030%, Ti: 0.01 to 0.30%, and optional elements, with the balance: Fe and unavoidable impurities, a steel microstructure of the base metal includes, in volume ratio, 95% or more of a ferritic phase, the nitrided layer is a layer that is present in a region from a surface of a rolled surface to a 0.05 ?m depth position in a sheet thickness direction, and an average nitrogen concentration in the nitrided layer is, in mass %, 0.80% or more.

Abstract: A ferritic stainless steel sheet is provided that has a predetermined chemical composition, wherein: a grain size number is 6.0 or more; the ferritic stainless steel sheet satisfies the formulas [A+B?9.0] and [X+Y?9.0] with respect to crystal orientation intensities of a ferrite phase obtained by X-ray diffraction; and the sheet thickness is 1.0 mm or more. A represents a {111}<112> crystal orientation intensity at a center portion of sheet thickness, B represents a {111}<112> crystal orientation intensity at a ? portion of the sheet thickness, X represents a {322}<236> crystal orientation intensity at a center portion of sheet thickness, and Y represents a {322}<236> crystal orientation intensity at a ? portion of the sheet thickness.

Abstract: A ferritic stainless steel sheet and a steel pipe as a material suitable for a heat-resistant component that is required to have especially excellent formability are provided. The ferritic stainless steel sheet contains 10 to 20 mass % of Cr and a predetermined amount of C, Si, Mn, P, S, Al and one or both of Ti and Nb, a {111}-orientation intensity being 5 or more and {411}-orientation intensity being less than 3 at a portion in the vicinity of a sheet-thickness central portion of the ferritic stainless steel sheet. Further, with similar composition and by setting {111}<110>-orientation intensity at 4.0 or more and {311}<136>-orientation intensity at less than 3.0, a relationship rm??1.0t+3.0 (t(mm): sheet thickness, rm: average r-value) is satisfied, thereby providing a ferritic stainless steel sheet and a steel pipe with excellent formability.

Abstract: A ferritic stainless steel sheet and a steel pipe as a material suitable for a heat-resistant component that is required to have especially excellent formability are provided. The ferritic stainless steel sheet contains 10 to 20 mass % of Cr and a predetermined amount of C, Si, Mn, P, S, Al and one or both of Ti and Nb, a {111}-orientation intensity being 5 or more and {411}-orientation intensity being less than 3 at a portion in the vicinity of a sheet-thickness central portion of the ferritic stainless steel sheet. Further, with similar composition and by setting {111}<110>-orientation intensity at 4.0 or more and {311}<136>-orientation intensity at less than 3.0, a relationship rm??1.0t+3.0 (t(mm): sheet thickness, rm: average r-value) is satisfied, thereby providing a ferritic stainless steel sheet and a steel pipe with excellent formability.

Abstract: A ferritic stainless steel sheet and a steel pipe as a material suitable for a heat-resistant component that is required to have especially excellent formability are provided. The ferritic stainless steel sheet contains 10 to 20 mass % of Cr and a predetermined amount of C, Si, Mn, P, S, Al and one or both of Ti and Nb, a {111}-orientation intensity being 5 or more and {411}-orientation intensity being less than 3 at a portion in the vicinity of a sheet-thickness central portion of the ferritic stainless steel sheet. Further, with similar composition and by setting {111}<110>-orientation intensity at 4.0 or more and {311}<136>-orientation intensity at less than 3.0, a relationship rm??1.0t+3.0 (t (mm): sheet thickness, rm: average r-value) is satisfied, thereby providing a ferritic stainless steel sheet and a steel pipe with excellent formability.