The method of manufacturing steel material superior in the resistance to hydrogen-induced cracking resistance

摘要

PROBLEM TO BE SOLVED: To provide a steel exhibiting excellent hydrogen induced cracking resistance (HIC resistance) even in the case when it is used in a severe sour environment such as a line pipe for transporting crude oil, natural gas or the like including a large quantity of hydrogen sulfide, a pressure vessel or the like.SOLUTION: A steel having excellent hydrogen induced cracking resistance is characterized in that a base steel satisfies, by mass and as chemical composition, 0.01 to 0.20% C, 0.10 to 0.50% Si, 0.70 to 2.50% Mn, ≤0.03 (not including 0%) P, ≤0.003% (not including 0%) S, 0.005 to 0.10% Al and ≤0.01% (not including 0%) O, and in which ≥90% of the surface of the base steel is covered with an oxide layer having the average thickness of 1.0 to 100 μm and also including FeOby ≥70% by volume.