HIGH-STRENGTH PRECIPITATION-HARDENING STAINLESS STEEL, STAINLESS STEEL WIRE AND HIGH-STRENGTH FASTENING MEMBER USING THIS STEEL WIRE

摘要

PROBLEM TO BE SOLVED: To provide a high-strength precipitation-hardening stainless steel, a stainless steel wire and a high-strength fastening member using this steel wire.;SOLUTION: The high-strength precipitation-hardening semi-austenitic stainless steel showing an excellent cold workability contains at least 0.01-0.1 mass% C, ≤2 mass% Si, 2-4 mass% Mn, 4-8 mass% Ni, 12-18 mass% Cr, ≤2 mass% Mo, 1.5-4 mass% Cu, ≤0.5 mass% Nb and 0.05-0.25 mass% N, wherein C/N is ≤1, Ni-bal calculated by the formula: Ni-bal=Ni+27C+23N+0.1Mn+0.3 Cu-1.2(Cr+Mo)-0.5Si+10 is ≥-2, Ms (°C) calculated by the formula: Ms=1684-60.8Cr-89.2Ni-48.7Mn-40.6Si-2433(C+N) is ≤-100°C, Md₃₀ (°C) calculated by the formula: Md₃₀=551-462(C+N)-9.2Si-8.1Mn-13.7Cr-29(Ni+ Cu)-18.5Mo-68Nb is ≥-30°C, and the amount of austenite after a solution treatment is ≥80 vol.%.;COPYRIGHT: (C)2003,JPO