| 摘要 |
A thick steel plate and a UOE steel pipe having a high strength of at least X60 grade and improved resistance to HIC have a chemical composition consisting essentially of, in mass percent, C: 0.02-0.07%, Si: 0.05-0.50%, Mn: 1.1-1.6%, P: at most 0.015%, S: at most 0.002%, Nb: 0.005-0.060%, Ti: 0.005-0.030%, Al: 0.005-0.06%, Ca: 0.0005-0.0060%, N: 0.0015-0.007%, at least one of Cu, Ni, Cr, and Mo in a total amount of greater than 0.1% and less than 1.5%, and a remainder of Fe and impurities, wherein the degrees of segregation of Nb and Ti are both at most 2.0, and the ratio of (the degree of Nb segregation)/(the degree of Mn segregation) and the ratio of (the degree of Ti segregation)/(the degree of Mn segregation) are both at least 1.0 and at most 1.5. |
