HIGH-STRENGTH HOT-ROLLED STEEL COIL FOR ELECTRIC RESISTANCE WELDED LINE PIPE HAVING EXCELLENT SOUR RESISTANCE AND METHOD FOR MANUFACTURING THE SAME

摘要

provides huyuk hot-rolled steel sheet for line pipe excellent in sour Castle. Art huyuk hot rolled steel sheet, C: 0.01 ~ 0.07%, Si: 0.40% or less, Mn: 0.5 ~ 1.4%, Al: less than 0.1%, Nb: 0.01 ~ 0.15%, V: less than 0.1%, Ti: 0.03% or less , N: 0.008% or less to be contained, and further Nb, V, Ti has, Nb + V + Ti 0.15 satisfactory, and further Cm 0.12 or less to satisfy the composition and, bainite phase or bay age tick ferrite phase area ryulro have an organization that contains more than 95%, and the highest hardness of the plate thickness is less than 220 HV, the high yield strength and high-strength than 450 has the toughness, and excellent in sour sex.