AUSTENITIC STAINLESS STEEL
An austenitic stainless steel with a chemical composition including in terms of mass %: 0.05 to 0.13% of C, 0.10 to 1.00% of Si, 0.10 to 3.00% of Mn, 0.040% or less of P, 0.020% or less of S, 17.00 to 19.00% of Cr, 12.00 to 15.00% of Ni, 2.00 to 4.00% of Cu, 0.01 to 2.00% of Mo, 2.00 to 5.00% of W, 2.50 to 5.00% of 2Mo+W, 0.01 to 0.40% of V, 0.05 to 0.50% of Ti, 0.15 to 0.70% of Nb, 0.001 to 0.040% of Al, 0.0010 to 0.0100% of B, 0.0010 to 0.0100% of N, 0.001 to 0.20% of Nd, 0.002% or less of Zr, 0.001% or less of Bi, 0.010% or less of Sn, 0.010% or less of Sb, 0.001% or less of Pb, 0.001% or less of As, 0.020% or less of Zr+Bi+Sn+Sb+Pb+As, 0.0090% or less of O, and a remainder including Fe and impurities.
1 . An austenitic stainless steel with a chemical composition consisting of in terms of mass %:
0.05 to 0.13% of C,
0.10 to 1.00% of Si,
0.10 to 3.00% of Mn,
0.040% or less of P,
0.020% or less of S,
17.00 to 19.00% of Cr,
12.00 to 15.00% of Ni,
2.00 to 4.00% of Cu,
0.01 to 2.00% of Mo,
2.00 to 5.00% of W,
2.50 to 5.00% of 2Mo+W,
0.01 to 0.40% of V,
0.05 to 0.50% of Ti,
0.15 to 0.70% of Nb,
0.001 to 0.040% of Al,
0.0010 to 0.0100% of B,
0.0010 to 0.0100% of N,
0.001 to 0.20% of Nd,
0.002% or less of Zr,
0.001% or less of Bi,
0.010% or less of Sn,
0.010% or less of Sb,
0.001% or less of Pb,
0.001% or less of As,
0.020% or less of Zr+Bi+Sn+Sb+Pb+As,
0.0090% or less of O,
0.80% or less of Co,
0.20% or less of Ca,
0.20% or less of Mg,
0.20% or less in total of one or more of Y, Sc, Ta, Hf, Re or lanthanoid elements other than Nd, and
a remainder consisting of Fe and impurities;
wherein an effective M content Meff defined by the following Formula (1) is 0.0001 to 0.250%:
Effective M content Meff=Nd+13·(B−11·N/14)−1.6·Zr Formula (1)
wherein in Formula (1), each element symbol represents a content (mass %) of each element.
2 . The austenitic stainless steel according to claim 1 , wherein the chemical composition comprises, in terms of mass %, one or more of: 0.01 to 0.80% of Co, 0.0001 to 0.20% of Ca, or 0.0005 to 0.20% of Mg.
3 . The austenitic stainless steel according to claim 1 , wherein the chemical composition comprises, in terms of mass %, 0.001 to 0.20% in total of one or more of Y, Sc, Ta, Hf, Re or lanthanoid elements other than Nd.
4 . The austenitic stainless steel according to claim 1 , wherein an ASTM grain size number of a metallic structure thereof is 7 or less.
5 . The austenitic stainless steel according to claim 1 , wherein a creep rupture strength at 700° C. and 10,000 hours is 140 MPa or more.
6 . The austenitic stainless steel according to claim 1 , wherein the effective M content Meff is 0.002 to 0.250%.
7 . The austenitic stainless steel according to claim 2 , wherein the chemical composition comprises, in terms of mass %, 0.001 to 0.20% in total of one or more of Y, Sc, Ta, Hf, Re or lanthanoid elements other than Nd.
8 . The austenitic stainless steel according to claim 2 , wherein an ASTM grain size number of a metallic structure thereof is 7 or less.
9 . The austenitic stainless steel according to claim 2 , wherein a creep rupture strength at 700° C. and 10,000 hours is 140 MPa or more.
10 . The austenitic stainless steel according to claim 2 , wherein the effective M content Meff is 0.002 to 0.250%.
11 . The austenitic stainless steel according to claim 3 , wherein an ASTM grain size number of a metallic structure thereof is 7 or less.
12 . The austenitic stainless steel according to claim 3 , wherein a creep rupture strength at 700° C. and 10,000 hours is 140 MPa or more.
13 . The austenitic stainless steel according to claim 3 , wherein the effective M content Meff is 0.002 to 0.250%.
14 . An austenitic stainless steel with a chemical composition comprising in terms of mass %:
0.05 to 0.13% of C,
0.10 to 1.00% of Si,
0.10 to 3.00% of Mn,
0.040% or less of P,
0.020% or less of S,
17.00 to 19.00% of Cr,
12.00 to 15.00% of Ni,
2.00 to 4.00% of Cu,
0.01 to 2.00% of Mo,
2.00 to 5.00% of W,
2.50 to 5.00% of 2Mo+W,
0.01 to 0.40% of V,
0.05 to 0.50% of Ti,
0.15 to 0.70% of Nb,
0.001 to 0.040% of Al,
0.0010 to 0.0100% of B,
0.0010 to 0.0100% of N,
0.001 to 0.20% of Nd,
0.002% or less of Zr,
0.001% or less of Bi,
0.010% or less of Sn,
0.010% or less of Sb,
0.001% or less of Pb,
0.001% or less of As,
0.020% or less of Zr+Bi+Sn+Sb+Pb+As,
0.0090% or less of O,
0.80% or less of Co,
0.20% or less of Ca,
0.20% or less of Mg,
0.20% or less in total of one or more of Y, Sc, Ta, Hf, Re or lanthanoid elements other than Nd, and
a remainder comprising Fe and impurities;
wherein an effective M content Meff defined by the following Formula (1) is 0.0001 to 0.250%:
Effective M content Meff=Nd+13·(B−11·N/14)−1.6·Zr Formula (1)
wherein in Formula (1), each element symbol represents a content (mass %) of each element.
15 . The austenitic stainless steel according to claim 14 , wherein the chemical composition comprises, in terms of mass %, one or more of: 0.01 to 0.80% of Co, 0.0001 to 0.20% of Ca, or 0.0005 to 0.20% of Mg.
16 . The austenitic stainless steel according to claim 14 , wherein the chemical composition comprises, in terms of mass %, 0.001 to 0.20% in total of one or more of Y, Sc, Ta, Hf, Re or lanthanoid elements other than Nd.
17 . The austenitic stainless steel according to claim 14 , wherein an ASTM grain size number of a metallic structure thereof is 7 or less.
18 . The austenitic stainless steel according to claim 14 , wherein a creep rupture strength at 700° C. and 10,000 hours is 140 MPa or more.
19 . The austenitic stainless steel according to claim 14 , wherein the effective M content Meff is 0.002 to 0.250%.