Abstract: A martensitic stainless steel sheet has a composition containing, (mass %), from 0.10 to 0.15% of C, from 0.05 to 0.80% of Si, from 0.05 to 2.00% of Mn, 0.040% or less of P, 0.003% or less of S, from 0.05 to 0.50% of Ni, from 11.0 to 15.0% of Cr, from 0.02 to 0.50% of Cu, from 0.005 to 0.06% of N, from 0.001 to 0.20% of Al, from 0 to 1.00% of Mo, from 0 to 0.50% of V, from 0 to 0.01% of B, balance Fe and unavoidable impurities. An M value=420C?11.5Si+7Mn+23Ni?11.5Cr?12Mo?10V+9Cu?52Al+470N+189 is 100 or more. A carbonitride number density having a circle equivalent diameter of 1.0 ?m or more is 15.0 or less per 0.01 mm2. 0.2% yield strength is 1,100 N/mm2 or more.

Abstract: A martensitic stainless steel sheet has a composition containing, (mass %), from 0.10 to 0.15% of C, from 0.05 to 0.80% of Si, from 0.05 to 2.00% of Mn, 0.040% or less of P, 0.003% or less of S, from 0.05 to 0.50% of Ni, from 11.0 to 15.0% of Cr, from 0.02 to 0.50% of Cu, from 0.005 to 0.06% of N, from 0.001 to 0.20% of Al, from 0 to 1.00% of Mo, from 0 to 0.50% of V, from 0 to 0.01% of B, balance Fe and unavoidable impurities. An M value=420C?11.5Si+7Mn+23Ni?11.5Cr?12Mo?10V+9Cu?52Al+470N+189 is 100 or more. A carbonitride number density having a circle equivalent diameter of 1.0 ?m or more is 15.0 or less per 0.01 mm2. 0.2% yield strength is 1,100 N/mm2 or more.

Abstract: Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of ?max, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less Al2O3, 20 to 60 mass % SiO2, and 15 to 70 mass % MnO.

Abstract: [Problem] To provide a raw material steel sheet for providing a high strength nonmagnetic austenitic stainless steel material that has a high elastic limit stress and excellent toughness. [Solution to Problem] An austenitic stainless steel sheet containing 0.12% or less of C, from 0.30 to 3.00% of Si, from 2.0 to 9.0% of Mn, from 7.0 to 15.0% of Ni, from 11.0 to 20.0% of Cr, and 0.30% or less of N, and further containing at least one kind of 3.0% or less of Mo, 1.0% or less of V, 1.0% or less of Nb, 1.0% or less of Ti, and 0.010% or less of B, all in terms of percentage by mass, with the balance of Fe and unavoidable impurities, having a component composition having a Ni equivalent of 19.0 or more, having a value of d?1/2 of 0.40 or more, wherein d (?m) represents an average austenitic crystal grain diameter, and having a property that provides a magnetic permeability ? of 1.0100 or less after subjected to cold rolling with an equivalent strain of 0.50 or more.

Abstract: A thin steel sheet contains, in terms of percentage by mass, from 0.010 to 0.200% of C, more than 2.00% and 4.00% or less of Si, from 0.01 to 3.00% of Mn, 3.00% or more and less than 10.00% of Ni, from 11.00 to 20.00% of Cr, from 0.010 to 0.200% of N, from 0 to 3.00% of Mo, from 0 to 1.00% of Cu, from 0 to 0.008% of Ti, from 0 to 0.008% of Al, and the balance of Fe, with unavoidable impurities; and having a number density of a non-metallic inclusion lining up with an interparticle distance in the rolling direction of 20 mm or less and an interparticle distance in the sheet thickness direction of 10 mm or less that has a length in the rolling direction of 40 mm or more of 3.0 or less per square millimeter on the L cross section.

Abstract: A hot rolled austenitic stainless steel sheet contains 0.030 to 0.300% of C, from 0.30 to 3.20% of Si, from 0.90 to 17.00% of Mn, from 1.00 to 8.00% of Ni, from 14.00 to 19.00% of Cr, from 0.50 to 3.50% of Cu, from 0.045 to 0.250% of N, from 0.0001 to 0.0300% of Al, from 0 to 0.50% of V, from 0 to 0.50% of Nb, from 0 to 0.30% of Ti, and from 0 to 0.010% of B, all in terms of percentage by mass, with the balance of Fe and unavoidable impurities, has a converted average composition of an oxide based inclusion that contains 30% by mass or less of Al2O3, 60% by mass or less of SiO2, and 15% by mass or more of MnO, and satisfies MnO3—3SiO2+110. Anisotropy of workability and fatigue resistance characteristics caused by an oxide based inclusion is decreased.

Abstract: A fatigue testing device 1 comprises a fixing member 4 constituted by a lower jig 2 and an upper jig 3. The lower jig 2 and the upper jig 3 are fixed with a bolt 5, and a sheet or plate-shaped metal plate 6 is fixed in a cantilever state such that it is interposed between the lower jig 2 and the upper jig 3. The lower jig 2 has a fixing surface 2a to which the metal sheet or plate 6 is fixed, and the fixing surface 2a has a curved shape such that the space between the fixing surface 2a and the metal sheet or plate 6 increases with increasing distance from the location where the metal sheet or plate 6 is fixed to the fixing surface 2a. The upper jig 3 also has a fixing surface 3a to which the metal sheet or plate 6 is fixed, and the fixing surface 3a has a curved shape such that the space between the fixing surface 3a and the metal sheet or plate 6 increases with increasing distance from the location where the metal sheet or plate 6 is fixed to the fixing surface 3a.

Abstract: A hot rolled austenitic stainless steel sheet contains 0.030 to 0.300% of C, from 0.30 to 3.20% of Si, from 0.90 to 17.00% of Mn, from 1.00 to 8.00% of Ni, from 14.00 to 19.00% of Cr, from 0.50 to 3.50% of Cu, from 0.045 to 0.250% of N, from 0.0001 to 0.0300% of Al, from 0 to 0.50% of V, from 0 to 0.50% of Nb, from 0 to 0.30% of Ti, and from 0 to 0.010% of B, all in terms of percentage by mass, with the balance of Fe and unavoidable impurities, has a converted average composition of an oxide based inclusion that contains 30% by mass or less of Al2O3, 60% by mass or less of SiO2, and 15% by mass or more of MnO, and satisfies MnO3-3SiO2+110. Anisotropy of workability and fatigue resistance characteristics caused by an oxide based inclusion is decreased.

Abstract: Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of ?max, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less Al2O3, 20 to 60 mass % SiO2, and 15 to 70 mass % MnO.

Abstract: A fatigue testing device 1 comprises a fixing member 4 constituted by a lower jig 2 and an upper jig 3. The lower jig 2 and the upper jig 3 are fixed with a bolt 5, and a sheet or plate-shaped metal plate 6 is fixed in a cantilever state such that it is interposed between the lower jig 2 and the upper jig 3. The lower jig 2 has a fixing surface 2a to which the metal sheet or plate 6 is fixed, and the fixing surface 2a has a curved shape such that the space between the fixing surface 2a and the metal sheet or plate 6 increases with increasing distance from the location where the metal sheet or plate 6 is fixed to the fixing surface 2a. The upper jig 3 also has a fixing surface 3a to which the metal sheet or plate 6 is fixed, and the fixing surface 3a has a curved shape such that the space between the fixing surface 3a and the metal sheet or plate 6 increases with increasing distance from the location where the metal sheet or plate 6 is fixed to the fixing surface 3a.

Abstract: [Problem] To provide a raw material steel sheet for providing a high strength nonmagnetic austenitic stainless steel material that has a high elastic limit stress and excellent toughness. [Solution to Problem] An austenitic stainless steel sheet containing 0.12% or less of C, from 0.30 to 3.00% of Si, from 2.0 to 9.0% of Mn, from 7.0 to 15.0% of Ni, from 11.0 to 20.0% of Cr, and 0.30% or less of N, and further containing at least one kind of 3.0% or less of Mo, 1.0% or less of V, 1.0% or less of Nb, 1.0% or less of Ti, and 0.010% or less of B, all in terms of percentage by mass, with the balance of Fe and unavoidable impurities, having a component composition having a Ni equivalent of 19.0 or more, having a value of d?1/2 of 0.40 or more, wherein d (?m) represents an average austenitic crystal grain diameter, and having a property that provides a magnetic permeability of 1.0100 or less after subjected to cold rolling with an equivalent strain of 0.50 or more.