The pipeline steel comprises the following components in percentage by weight: 0.051 to 0.09 percent of C, 0.1 to 0.4 percent of Si, 1.5 to 1.9 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.002 percent of S, less than or equal to 0.19 percent of Cu, 0.05 to 0.19 percent of Ni, 0.11 to 0.35 percent of Cr, more than or equal to 0.6 percent and less than or equal to 1.1 percent of Ni + 3Cr, less than or equal to 0.13 percent of Mo, 0.02 to 0.08 percent of Nb, 0.005 to 0.035 percent of Ti, 0.001 to 0.004 percent of Ca, 0.010 to 0.045 percent of Alt, less than or equal to 0.006 percent of N, less than or equal to 0.0003 percent of B, less than or equal to 0.005 percent of O, less than or equal to 0.0002 percent of H and the balance of The method mainly aims at the welded
pipe with the wall thickness of 25-40 mm and the
caliber of phi 1016-phi 1422 mm, the yield strength of the welded
pipe is 555-665 MPa, the tensile strength is larger than or equal to 625 MPa, the-20 DEG C low-temperature
impact energy is higher than 1600 J, the-10 DEG C full wall thickness DWTT shear fracture area percentage is larger than 85%, meanwhile, the longitudinal yield strength is 530-640 MPa, the
yield ratio is smaller than or equal to 0.85, and the uniform
ductility is larger than or equal to 7%.