MARTENSITIC STAINLESS STEEL SEAMLESS STEEL TUBE FOR OIL WELL PIPES, AND METHOD FOR PRODUCING SAME

摘要

The purpose of the present invention is to provide: a martensitic stainless steel seamless steel pipe for oil well pipes having yield stress of at least 758 MPa, and excellent resistance to sulfide stress corrosion cracking; and a production method therefor. The martensitic stainless steel seamless steel tube for oil well pipes has a composition comprising, in % by mass: at least 0.010% C; no more than 0.5% Si; 0.05-0.50% Mn; no more than 0.030% P; no more than 0.005% S; 4.6-8.0% Ni; 10.0-14.0% Cr; 1.0-2.7% Mo; no more than 0.1% Al; 0.005-0.2% V; no more than 0.1% N; 0.010-0.054% Ti; 0.01-1.0% Cu; and 0.01-1.0% Co; with C, Mn, Cr, Cu, Ni, Mo, W, N and Ti satisfying predetermined relational expressions, and the remainder being made up of Fe and unavoidable impurities.