The steel and the production mannered null mass which for the oil well are superior in resistance sulfide stress corrosion

摘要

PROBLEM TO BE SOLVED: To provide oil-well steel having excellent sulfide stress corrosion cracking resistance and manufacturable by means of round CC(continuous casting) with high production efficiency and its manufacturing method and also to provide oil-well steel having excellent cracking resistance and its manufacturing method.;SOLUTION: In the oil-well steel having excellent sulfide stress corrosion cracking resistance, a composition of Ca-type nonmetallic inclusions comprises ≥50 mass%, in total, of CaS and CaO and also comprises 50 mass% compound oxide of Ca and Al, and the hardness of the steel ranges from HRC 21 to 30, and further, the total content X (mass%) of CaO and CaS satisfies the inequality, 100-X≤120-(10/3)×HRC. The method for manufacturing the steel is also provided.;COPYRIGHT: (C)2002,JPO