Patent ID: 7083686

Claim:
A steel product for oil country tubular good, comprising, in mass %, 0.10% to 0.35% C, 0.10% to 0.50% Si, 0.10% to 0.80% Mn, up to 0.030% P, up to 0.010% S, 0.30% to 1.20% Cr, 0.20% to 1.00% Mo, 0.005% to 0.40% V, 0.005% to 0. 100% Al, up to 0.0100% N, up to 0.0010% H, 0 to 0.01% Ca, 0 to 0.050% Ti, 0 to 0.050% Nb, and 0 to 0.0050% B, and the balance of Fe and impurities, the contents of said Cr, Mo, and V and the grain size GS satisfying expression (1): 0.7≦(1.5×Cr+2.5×Mo+V)− GS/ 10≦2.6 (1).