Manufacturing method of economical L360NX52N line pipe

The invention discloses a manufacturing method of an economical L360NX52N pipeline pipe, an L360N/X52N pipeline pipe round pipe blank with qualified chemical components and quality is adopted, the carbon equivalent CEIIW in steel is less than or equal to 0.43, and the sequence of the production process flow is as follows: pipe blank heating, perforating, continuous rolling, sizing, cooling, saw cutting, flaw detection, water pressure treatment, manual inspection and detection analysis, the economical L360N/X52N is produced through an online normalizing process, low-carbon production is achieved, and the carbon equivalent CEIIW in the steel is smaller than or equal to 0.43. The mechanical properties of the steel pipe manufactured by the invention meet the following requirements: the yield strength is 380-530 MPa; the tensile strength is 500 to 760 MPa; the yield ratio is less than or equal to 0.80; the ductility is greater than or equal to 39%; the transverse impact value AKV at 0 DEG C is greater than or equa