| 摘要 |
Provided is a low alloy steel pipe for oil wells, which has a yield strength of 793 MPa or more and excellent SSC resistance. A low alloy steel pipe for oil wells according to the present invention has a chemical composition that contains, in mass%, 0.25-0.35% of C, 0.05-0.50% of Si, 0.10-1.50% of Mn, 0.40-1.50% of Cr, 0.40-2.00% of Mo, 0.05-0.25% of V, 0.010-0.040% of Nb, 0.002-0.050% of Ti, 0.005-0.10% of sol. Al, 0.007% or less of N, 0.0001-0.0035% of B and 0-0.005% of Ca, with the balance made up of Fe and impurities. The number of cementites having a circle-equivalent diameter of 200 nm or more is 100 pieces/100 μm2 or more in the structure. This low alloy steel pipe for oil wells has a yield strength of 793 MPa or more. |
