METHOD FOR SMELTING STEEL FOR LINE PIPE HAVING EXCELLENT SULFIDE STRESS CRACK RESISTANCE OF WELD ZONE

摘要

PURPOSE: To execute ladle refining of steel having the excellent sulfide stress crack resistance in moist hydrogen sulfide atmosphere. ;CONSTITUTION: The steel consisting, by weight %, of 0.03 to 0.09 C, 0.1 to 0.4 Si, 0.5 to 1.0 Mn, ≤0.015 P, (0.0010 S, 0.010 to 0.050 Nb, 0.005 to 0.03 Al, 0.001 to 0.003 Ca, 0.005 to 0.025 Ti, ≤0.0050 O and (%Ca{1-98(%0)}/(%S)1.7 and 0.07(%Ca)/(%Al)0.17 and 6(%Si)/(%Al)25 and the balance iron and inevitable impurities is subjected to ladle refining.;COPYRIGHT: (C)1994,JPO