HIGH-STRENGTH SEAMLESS STAINLESS STEEL PIPE FOR OIL COUNTRY TUBULAR GOODS AND METHOD FOR PRODUCING THE SAME

Provided herein is a high-strength seamless stainless steel pipe for oil country tubular goods that excels in low-temperature toughness, carbon dioxide corrosion resistance, sulfide stress corrosion cracking resistance, and sulfide stress cracking resistance. The high-strength seamless stainless steel pipe contains, in mass%, C: 0.05% or less, Si: 0.5% or less, Mn: 0.15 to 1.0%, P: 0.030% or less, S: 0.005% or less, Cr: 14.5 to 17.5%, Ni: 3.0 to 6.0%, Mo: 2.7 to 5.0%, Cu: 0.3 to 4.0%, W: 0.1 to 2.5%, V: 0.02 to 0.20%, Al: 0.10% or less, N: 0.15% or less, and the balance being Fe and unavoidable impurities. C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfy a specific formula. Cu, Mo, W, Cr, and Ni satisfy another specific formula. The high-strength seamless stainless steel pipe has more than 45% martensite phase, 10 to 45% ferrite phase, and 30% or less retained austenite phase. The total amount of precipitated Cr, precipitated Mo, and precipitated W is 0.75 mass% or less. Thus the high-strength seamless stainless steel pipe has a yield strength of 862 MPa or more.