The invention discloses pipeline steel resistant to
carbon dioxide corrosion and a preparation method thereof, and belongs to the technical field of pipeline steel manufacturing. The pipeline steel comprises the following chemical components: not more than 0.05 percent of C, 0.2-0.3 percent of Si, 0.50-0.80 percent of Mn, not more than 0.020 percent of P, not more than 0.010 percent of S, 4.0-7.0 percent of Cr, not more than 0.080 percent of Nb, not more than 0.050 percent of Ti, not more than 0.080 percent of V, 0.2-0.50 percent of Mo, not more than 0.30 percent of Ni, not more than 0.5 percent of Cu, not more than 0.010 percent of N, not more than 0.0010 percent of B and the balance of Fe and impurities. A higher-
toughness steel plate of the pipeline steel resistant to the
carbon dioxide corrosion is obtained finally through the processes such as
smelting,
casting,
forging and pressing, heating, rolling, cooling,
quenching and
tempering. The production process is simple, the operation is feasible, the production cost is low, the
corrosion rate of the steel can be lowered to 0.0581 mm / a, the yield strength is greater than 500 MPa, the tensile strength is greater than 550 MPa, the elongation is greater than 25 percent, the
impact energy at the temperature of minus 20 DEG C is greater than 150 J, and the DWTT mean value at the temperature of minus 20 DEG C is 100 percent.