High Mn austenitic stainless steel for hydrogen excellent in weldability, welded joint and equipment for hydrogen using the same, and method of manufacturing welded joint

摘要

In this austenitic stainless steel, 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, Ca: It contains one or both of 0.01% or less and Al: 0.3% or less, with the balance being Fe and unavoidable impurities, satisfying the following expression (1). [Ni] + [Cu] +12.93 [C] +1.11 [Mn] +0.72 [Cr] +0.88 [Mo] −0.27 [Si] +7.55 [N] ≧ 29.3・ Expression (1)