Quenched and tempered pipeline steel for X70-grade pipe pile and preparation method of quenched and tempered pipeline steel

The invention discloses quenched and tempered pipeline steel for an X70-grade pipe pile and a manufacturing method of the quenched and tempered pipeline steel. The quenched and tempered pipeline steel is prepared from the following components, by weight percentage, 0.12%-0.16% of C, 0.25%-0.40% of Si, 1.45%-1.60% of Mn, smaller than or equal to 0.008% of P, smaller than or equal to 0.003% of S, 0.03%-0.05% of Nb, 0.015%-0.030% of Ti, 0.030%-0.050% of V, 0.15%-0.25% of Cr and the balance Fe and inevitable impurity elements. A manufacturing method comprises the following steps of KR, converter smelting, LF, RH, CCM, casting blank slow cooling for 48 h, plate blank heating, high-pressure water descaling, rough rolling stage, finish rolling stage, straightening, cooling, shot blasting, quenching, tempering and straightening. The alloy is low in cost and good in welding performance, the impact energy at 0 DEG C is larger than 150 J, and the alloy has the advantages of being low in cost, high in strength and resist