Abstract: To provide an austenitic stainless steel material having a high creep strength and a high creep ductility even in a high-temperature environment at 800° C. or more. An austenitic stainless steel material according to the present disclosure has a chemical composition that includes, in mass %: C: 0.060% or less; Si: 1.0% or less; Mn: 2.00% or less; P: 0.0010 to 0.0400%; S: 0.010% or less; Cr: 10 to 25%; Ni: 25 to 45%; Nb: 0.2 to 2.0%; W: 2.5 to 6.0%; B: 0.0010 to 0.0100%: Al: 2.5 to 4.5%; and the balance being Fe and impurities, and satisfies Formulae (1) and (2), and the sum of the content of dissolved Nb and the content of dissolved W is 3.2 mass % or more. (W/184+Nb/93)/(C/12)?5.5??(1) (W/184+Nb/93)/(B/11)?450??(2) In Formulae (1) and (2), the content in mass % of the corresponding element is substituted for each symbol of element.

Abstract: To provide an austenitic stainless steel material having a high creep strength and a high creep ductility even in a high-temperature environment at 800° C. or more. An austenitic stainless steel material according to the present disclosure has a chemical composition that includes, in mass %: C: 0.060% or less; Si: 1.0% or less; Mn: 2.00% or less; P: 0.0010 to 0.0400%; S: 0.010% or less; Cr: 10 to 25%; Ni: 25 to 45%; Nb: 0.2 to 2.0%; W: 2.5 to 6.0%; B: 0.0010 to 0.0100%: Al: 2.5 to 4.5%; and the balance being Fe and impurities, and satisfies Formulae (1) and (2), and the sum of the content of dissolved Nb and the content of dissolved W is 3.2 mass % or more. (W/184+Nb/93)/(C/12)?5.5??(1) (W/184+Nb/93)/(B/11)?450??(2) In Formulae (1) and (2), the content in mass % of the corresponding element is substituted for each symbol of element.

Abstract: There is provided an austenitic heat resistant alloy having a chemical composition that contains, in mass percent: C: 0.03 to 0.25%, Si: 0.01 to 2.0%, Mn: 0.10 to 0.50%, P: 0.030% or less, S: 0.010% or less, Cr: 13.0 to 30.0%, Ni: 25.0 to 45.0%, Al: 2.5 to 4.5%, Nb: 0.01 to 2.00%, N: 0.05% or less, Ti: 0 to 0.20%, W: 0 to 6.0%, Mo: 0 to 4.0%, Zr: 0 to 0.10%, B: 0 to 0.0100%, Cu: 0 to 5.0%, REM: 0 to 0.10%, Ca: 0 to 0.050%, Mg: 0 to 0.050%, and the balance: Fe and impurities.

Abstract: Provided is an austenitic stainless steel having excellent anti-carburizing properties even in a high temperature carburizing environment, and an excellent hot workability in its production. The austenitic stainless steel according to the present embodiment includes a chemical composition consisting of, in mass percent, C: 0.03 to less than 0.25%, Si: 0.01 to 2.0%, Mn: 2.0% or less, Cr: 10 to less than 22%, Ni: more than 30.0% to 40.0%, Al: more than 2.5% to less than 4.5%, Nb: 0.01 to 3.5%, Ca: 0.0005 to 0.05%, Mg: 0.0005 to 0.05%, and N: 0.03% or less, with the balance being Fe and impurities. In the austenitic stainless steel, a Cr concentration CCrz,23 n its outer layer and an Al concentration CAln the outer layer satisfy Formula (1) for a Cr concentration CCr in an other-than-outer-layer region and an Al concentration CAl in the other-than-outer-layer region. 0.40?(CCrCCr/CAl)?0.

Abstract: Provided is an austenitic heat resistant alloy having high creep strength and high toughness even in a high temperature environment. This austenitic heat resistant alloy has a chemical composition consisting of: in mass %, C: 0.03 to less than 0.25%, Si: 0.01 to 2.0%, Mn: not more than 2.0%, Cr: 10 to less than 30%, Ni: more than 25 to 45%, Al: more than 2.5 to less than 4.5%, Nb: 0.2 to 3.5%, N: not more than 0.025%, with the balance being Fe and impurities, wherein P and S in the impurities are respectively, P: not more than 0.04% and S: not more than 0.01%. In the structure, a total volume ratio of precipitates having a circle equivalent diameter of not less than 6 ?m is not more than 5%.