Abstract: A stainless steel with reduced S and suppressed generation of hard inclusions. Inclusions with an equivalent circle diameter of 5 ?m or more, the number density of a first inclusion having the average composition of, in mass %, CaO: 0% or more and 15% or less, SiO2: 0% or more and 20% or less, Al2O3: 50% or more and 70% or less, and MgO: 10% or more and 40% or less is 0.5 inclusions/mm2 or less, the number density of a second inclusion having CaO: 10% or more and 70% or less, SiO2: 10% or more and 65% or less, Al2O3: 20% or less, MgO: 5% or more and 50% or less, and CaF2: 0% or more and 5% or less is 0.2 inclusions/mm2 or less, and the number density of a third inclusion having CaO: 5% or more and 40% or less, SiO2: 10% or more and 40% or less, Al2O3: 10% or more and 40% or less, MgO: 5% or more and 30% or less, and CaF2: 5% or more and 40% or less is 0.005 inclusions/mm2 or more and 0.5 inclusions/mm2 or less.

Abstract: This high strength austenitic stainless steel having excellent resistance to hydrogen embrittlement includes, in terms of mass %, C: 0.2% or less, Si: 0.2% to 1.5%, Mn: 0.5% to 2.5%, P: 0.06% or less, S: 0.008% or less, Ni: 10.0% to 20.0%, Cr: 16.0% to 25.0%, Mo: 3.5% or less, Cu: 3.5% or less, N: 0.01% to 0.50%; and O: 0.015% or less, with the balance being Fe and unavoidable impurities, in which an average size of precipitates is 100 nm or less and an amount of the precipitates is 0.001% to 1.0% in terms of mass %.

Abstract: This austenitic stainless steel contains, in terms of % by mass: C: 0.100% or less, Si: 3.00% or less, Mn: 0.01% or more and 5.00% or less, P: 0.100% or less, S: 0.0050% or less, Ni: 7.00% or more and 38.00% or less, Cr: 17.00% or more and 28.00% or less, Mo: 10.00% or less, and N: more than 0.100% and 0.400% or less, with a remainder being Fe and impurities, and a brightness difference ?L of a surface of a stainless steel is 5 or less.

Abstract: A welded structure including a base material made of duplex stainless steel and a welded portion formed by welding the base materials to each other, wherein the base material has a predetermined chemical composition, a volume fraction of a ferrite phase in a metallographic structure of a weld metal of the welded portion is 45 to 75%, a ratio of a hardness of the weld metal to a hardness of the base material is 0.80 to 1.20, and an amount of precipitates formed in the ferrite phase of the weld metal is less than 10% in area fraction.

Abstract: A stainless steel material including a base material made of ferritic stainless steel, a Cr oxide layer formed on a surface of the base material, and a spinel oxide layer formed on a surface of the Cr oxide layer, wherein a chemical composition of the base material satisfies [16.0?Cr+3×Mo?2.5×B?17×C?3?Si?35.0], a thickness of the Cr oxide layer (TCr) and a thickness of the spinel oxide layer (TS) satisfy [0.55?TCr/TS?6.7], the base material contains precipitate including one or more kinds selected from a M23C6, a M2B, a complex precipitate in which M2B acts as a precipitation nucleus, and M23C6 precipitates on a surface of the M2B, and a complex precipitate in which NbC acts as a precipitation nucleus, and M23C6 precipitates on a surface of the NbC, and a part of the precipitate protrude from the surface of the Cr oxide layer.

Abstract: A duplex stainless steel and method of manufacturing the same, said steel having an amount of Cr in an extraction residue [Cr] of 0.005 to 0.050% and an amount of Nb in an extraction residue [Nb] of 0.001 to 0.080%, the [Nb]/[Cr] ratio being 0.2 or more. By slow cooling down to 800° C., then fast cooling down to 600° C., it is possible to control the precipitation of chromium nitrides and niobium nitrides, and by making the ratio [Nb]/[Cr] 0.2 or more, it is possible to raise the corrosion resistance. Further, by reducing Mn to less than 2.0% and N to 0.25% or less, then adding a trace amount of Nb, the effect of raising the critical pitting temperature CPT is obtained.

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: Ferritic stainless steel securing corrosion resistance while being excellent in ridging resistance able to be stably provided, that is, ferritic stainless steel with excellent ridging resistance having a composition comprising, by mass %, C: 0.001 to 0.01%, Si: 0.3% or less, Mn: 0.3% or less, P: 0.04% or less, S: 0.01% or less, Cr: 10 to 21%, Al: 0.01 to 0.2%, Ti: 0.015 to 0.3%, O: 0.0005 to 0.0050%, N: 0.001 to 0.02%, Ca: 0.0015% or less, and Mg: 0.0003% to 0.

Abstract: The present invention has as its technical problem to prevent cracking when producing a steel sheet by ferritic stainless steel sheet and provide a ferritic stainless steel sheet excellent in toughness and a part using the same. To solve this technical problem, the present invention provides steel comprised of, by mass %, C: 0.001 to 0.030%, Si: 0.01 to 1.00%, Mn: 0.01 to 1.00%, P: 0.010 to 0.050%, S: 0.0002 to 0.0100%, Cr: 10.0 to 20.0%, N: 0.001 to 0.030%, Nb: 0.10 to 0.40%, B: 0.0002 to 0.0030%, Al: 0.005 to 0.100%, and a balance of Fe and unavoidable impurities in which the amount of solute Nb being less than or equal to a smaller value of 0.20 and (Nb content-0.08) mass %.

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 for an automobile brake disc rotor includes: 0.001 to 0.05 mass % of C; 0.001 to 0.05 mass % of N; 0.3 to 4.0 mass % of Si; 0.01 to 2.0 mass % of Mn; 0.01 to 0.05 mass % of P; 0.0001 to 0.02 mass % of S; 10 to 20 mass % of Cr; one or both of 0.001 to 0.5 mass % of Ti and 0.01 to 0.8 mass % of Nb; and a balance consisting of Fe and impurities. After a hot stamping treatment, a crystal grain size is in a range from 100 to 200 ?m, and precipitates each having a grain size of 500 nm or less are present at a density of 0.01 to 20 pieces per square micrometer.

Abstract: A bar-shaped steel product extends unidirectionally and has a chemical composition including, by mass %, 0.001 to 0.20% of C, 0.01 to 3.0% of Si, 0.01 to 2.0% of Mn, 0.01 to 5.0% of Ni, 7.0 to 35.0% of Cr, 0.01 to 5.0% of Mo, 0.01 to 3.0% of Cu, 0.001 to 0.10% of N, 0.2 to 2.0% of Nb, optional element(s), and a balance consisting of Fe and inevitable impurities, and has 0.5 or less of a rolling-direction-crystal-orientation RD//<100> fraction (an area ratio of crystal having 20 degrees or less of an orientation difference between a <100> orientation and a rolling direction).

Abstract: Provided is a black stainless steel sheet that has excellent weldability, that can ensure good toughness and corrosion resistance, and that can maintain the blackness of the surface thereof, even after being welded. This black ferrite-based stainless steel sheet having excellent weldability includes, as a base, a stainless steel containing, in mass %, 0.020% or less of C, 1.0% or less of Si, 0.35% or less of Mn, 0.04% or less of P, 0.005% or less of S, 11-25% of Cr, 1.0% or less of Mo, 0.020% or less of N, 0.4% or less of Al, 10(C+N) to 0.3% of Ti, 0.05% or less of Nb, and 0.01% or less of O, and has a surface in which an oxide coating is formed on the base, wherein the surface has a lightness index (L*) satisfying L*?45, chromaticity indices (a*, b*) satisfying ?5?a*?5 and ?5?b*?5, and a blackness (E) satisfying E=(L*2+a*2+b*2)1/2?45.

Abstract: Provided are a stainless steel sheet with good corrosion resistance, low contact resistance and good press workability without the use of expensive materials such as gold or rare metals, and a method of manufacture the same. A method of manufacturing a stainless steel sheet includes: preparing a slab having a chemical composition including, in mass %: 20 to 26% Cr, up to 0.1% N, up to 2.0% Si, etc. (step S1); performing hot rolling and cold rolling on the slab to produce a rolled steel sheet with a thickness of 50 to 200 ?m (step S2); an annealing step in which the rolled steel sheet is annealed and cooled in a gas atmosphere containing nitrogen (step S3); and pickling the rolled steel sheet after the annealing step with a solution containing a non-oxidizing acid (step S4). The stainless steel sheet has an N content of 0.6 to 2.0% by mass.

Abstract: This ferritic stainless steel includes: in terms of % by mass, C: 0.001% to 0.100%; Si: 0.01% to 5.00%; Mn: 0.01% to 2.00%; P: 0.050% or less; S: 0.0100% or less; Cr: 9.0% to 25.0%; Ti: 0.001% to 1.00%; Al: 0.001% to 5.000%; and N: 0.001% to 0.050%, with a balance being Fe and impurities, wherein in a region from a steel surface to a depth of 5 nm, and not exceeding a thickness of a passive film, a total amount of Al and Si is 1.0 atomic % or more, an amount of Cr is 10.0 atomic % or more, and an amount of Fe is 85.0 atomic % or less, in terms of cation fraction.

Abstract: This clear-coated stainless steel sheet (10) includes a stainless steel sheet (20), and a clear-coated film (30) formed on at least one surface (20a) of the stainless steel sheet (20) and having an average film thickness of 0.05 ?m or more and 3.00 ?m or less.

Abstract: This ferritic stainless steel sheet contains, by mass %: C: 0.001% to 0.020%; Si: 0.01% to 4.00%; Mn: 0.01% to 3.00%; P: 0.010% to 0.040%; S: 0.0001% to 0.0100%; Cr: 10.0% to 15.0%; N: 0.001% to 0.020%; Al: 0.50% to 10.0%; and either one or both of Ti: 0.05% to 0.40% and Nb: 0.05% to 0.40%, with the balance being Fe and unavoidable impurities, in which Cr/(Si+Al) is 10.0 or less, and a specific gravity is 7.6 g/cm3 or less.

Abstract: A Cr-based stainless steel sheet includes: 0.020 mass % or less of C; 1.00 mass % or less of Si; 1.00 mass % or less of Mn; 0.040 mass % or less of P; 0.0030 mass % or less of S; 10.0 to 18.0 mass % of Cr; 0.020 mass % or less of N; 0.10 mass % or less of Al; and one or both of 0.5 mass % or less of Nb and 0.5 mass % or less of Ti; in which a texture in a sheet surface satisfies (i) and (ii) below. (i) In the sheet surface, an area ratio of crystal grains ({211}±10-degree-oriented grains) whose orientation difference between a normal direction of the surface and a {211}-plane orientation is 10 degrees or less is less than 30%. (ii) For the {211}±10-degree-oriented grains, a length in a rolling direction and a length in a sheet width direction are each less than 0.15 mm on average.

Abstract: This austenitic stainless steel contains, by mass %: C: 0.3% or less, Si: 0.1% to 1.5%, Mn: 5.5% to 20%, P: 0.050% or less, S: 0.005% or less, Cr: 10% to 20%, Ni: 4.0% to 12%, N: 0.40% or less, Cu: 4.0% or less, O: 0.02% or less, and either one or both of Ca: 0.01% or less and Al: 0.3% or less, with a remainder being Fe and inevitable impurities, and the following Formula (1) is satisfied. [Ni]+[Cu]+12.93[C]+1.11[Mn]+0.72[Cr]+0.88[Mo]?0.27[Si]+7.55[N]?29.

Abstract: This ferritic stainless steel pipe contains, by mass %: C: 0.001% to 0.100%; Si: 0.01% to 2.00%; Mn: 0.01% to 2.00%; P: 0.001% to 0.05%; S: 0.0001% to 0.005%; Cr: 10.5% to 20.0%; Sn: 0.001% to 0.600%; Ti: 0.001% to 1.000%; Al: 0.001% to 0.100%; and N: 0.001% to 0.02%, with a balance being Fe and unavoidable impurities, the ferritic stainless steel pipe includes a pipe-end-thickened portion at a pipe end portion, and a gap distance d (?m) formed at the pipe end portion satisfies a relationship of d?Cr2/(1000Sn) (in the expression, Cr and Sn represent amounts (mass %) of respective elements).