HIGH STRENGTH LOW PERMEABILITY AUSTENITIC STAINLESS STEEL SHEET, METHOD OF PRODUCING THE SAME, AND METHOD OF PRODUCING WASHER FOR BOLT FASTENING

摘要

PROBLEM TO BE SOLVED: To provide a high nitrogen austenitic stainless steel sheet which has high strength and a low magnetic permeability.;SOLUTION: The invention is the hard material of a high strength low permeability austenitic stainless steel sheet having a composition comprising, by mass, 0.02 to 0.08% C, 0.2 to 1.0% Si, 0.2 to 2.5% Mn, 17.0 to 22.0% Cr, 7.0 to 9.0% Ni, 0.05 to 0.15% Nb and 0.12 to 0.30% N, and in which the content of P is controlled to ≤0.040% and S to ≤0.030%, and the balance Fe with inevitable impurities, and in which Md30N in formula (1): Md30N(°C)=551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+Cu)-18.5Mo-68Nb satisfies ≤-80°C. The steel sheet has a sheet thickness of 2 to 6 mm, a magnetic permeability of ≤1.2, a 0.2% proof stress of ≥880/mm², and a tensile strength of ≥1,130 N/mm².;COPYRIGHT: (C)2004,JPO&NCIPI