| 摘要 |
An electric resistance welded steel pipe for an oil well, including in terms of mass%: 0.02 to 0.14% of C, 0.05 to 0.50% of Si, 1.0 to 2.1% of Mn, 0.020% or less of P, 0.010% or less of S, 0.010 to 0.100% of Nb, 0.010 to 0.050% of Ti, 0.010 to 0.100% of Al, and 0.0100% or less of N, wherein the contents of Cu, Ni, Cr, Mo, V, and B are 0 to 0.50% of Cu, 0 to 1.00% of Ni, 0 to 0.50% of Cr, 0 to 0.30% of Mo, 0 to 0.10% of V, and 0 to 0.0030% of B, respectively, a remainder consisting of Fe and unavoidable impurities, and wherein in a case in which a full thickness specimen is subjected to a pipe axis direction tensile test, a tensile strength is 780 MPa or more, the ratio of a 0.2% proof stress to the tensile strength [0.2% proof stress/tensile strength] is 0.80 or more, and the ratio of a 2% flow stress to the tensile strength [2% flow stress/tensile strength] is from 0.85 to 0.98. |
