Stainless steel seamless pipe

A stainless steel seamless pipe having a composition comprising, in mass %,

• C:
• 0.06% or less,
• Si:
• 1.0% or less,
• Mn:
• 0.01% or more and 1.0% or less,
• P:
• 0.05% or less,
• S:
• 0.005% or less,
• Cr:
• 14.0% or more and 17.0% or less,
• Mo:
• more than 3.80% and 6.0% or less,
• Cu:
• more than 1.03% and 3.5% or less,
• Ni:
• 3.5% or more and 6.0% or less,
• Al:
• 0.10% or less,
• N:
• 0.10% or less, and
• O:
• 0.010% or less, and
• a balance being Fe and incidental impurities,
• wherein
• C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfy the following Formula (1):
• 13.0≤−5.9×(7.82+27C−0.91Si+0.21Mn−0.9Cr+Ni−1.1Mo+0.2Cu+11N)≤50.0 (1)
• where C, Si, Mn, Cr, Ni, Mo, Cu, and N represent the content of each element in mass %,
• the stainless steel seamless pipe has a microstructure that contains at least 40% martensitic phase, at most 60% ferrite phase, and at most 30% retained austenite phase by volume, and
• the stainless steel seamless pipe has a yield strength of 862 MPa or more.