Patent ID: 7767037
Filing Date: 2010-08-03
Classification: C21D,C22C,Y10S

Abstract:
1. A high strength stainless steel seamless pipe for use in oil wells, which has superior corrosion resistance, comprising on a mass percent basis: 0.005% to 0.05% of C; 0.05% to 0.5% of Si; 0.2% to 1.8% of Mn; 0.03% or less of P; 0.005% or less of S; 15.5% to 18% of Cr; 1.5% to 5% of Ni; 1% to 3.5% of Mo; 0.02% to 0.2% of V; 0.01% to 0.15% of N; 0.006% or less of 0; and the balance being Fe and unavoidable impurities, wherein the following equations (1) and (2) are satisfied wherein Cr, Ni, Mo, Cu, C, Si, Mn, and N represent the respective contents on a mass percent basis, and contains an austenite phase at a volume fraction between 2.6% and 30%, a ferrite phase at a volume fraction between 10% and 60% and a martensite phase as the balance of the volume fraction, and has a yield strength of 654 MPa or more.