HIGH-STRENGTH AUSTENITIC STAINLESS STEEL FOR HIGH-PRESSURE HYDROGEN GAS

摘要

There is provided an austenitic stainless steel for high-pressure hydrogen gas consisting, by mass percent, of C: 0.10% or less, Si: 1.0% or less, Mn: 3% or more to less than 7%, Cr: 15 to 30%, Ni: 10% or more to less than 17%, Al: 0.10% or less, N: 0.10 to 0.50%, and at least one kind of V: 0.01 to 1.0% and Nb: 0.01 to 0.50%, the balance being Fe and impurities, wherein in the impurities, the P content is 0.050% or less and the S content is 0.050% or less, the tensile strength is 800 MPa or higher, the grain size number (ASTM E112) is No. 8 or higher, and alloy carbo-nitrides having a maximum diameter of 50 to 1000 nm are contained in the number of 0.4/µm 2 or larger in cross section observation.