HIGH-STRENGTH Cr-Ni ALLOY PRODUCT AND SEAMLESS OIL WELL PIPES MADE BY USINFG THE SAME

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The invention provides a high-strength Cr-Ni alloy product excellent in hot workability and stress corrosion cracking resistance and seamless oil well pipes made by using the same. A high-strength Cr-Ni alloy product and a seamless oil well pipe, characterized by containing by mass C : 0.05% or below, Si : 0.05 to 1.0%, Mn : 0.01 to less than 3.0%, P : 0.05% or below, S : 0.005% or below, Cu : 0.01 to 4%, Ni : 25 to less than 35%, Cr : 20 to 30%, Mo : 0.01 to less than 4.0%, N : 0.10 to 0.30%, Al : 0.03 to 0.30%, O(oxygen) : 0.01% or below, and REM (rare earth elements) : 0.01 to 0.20% with the balance consisting of Fe and impurities and by satisfying the relationship (1) : NŒP/REM ≤ 0.40... (1) (wherein P, N and REM represent contents (mass%) of P, N and REM respectively), with the proviso that Fe may be partially replaced by at least one member selected from among W, Ti, Nb, Zr, V, Ca and Mg.