Steel for vanadium alloying straight electric resistance welded petroleum casing pipe and manufacturing method thereof

The invention discloses steel for vanadium alloying straight electric resistance welded petroleum casing pipe and a manufacturing method thereof, and belongs to the technical field of production of steel hot-rolled steel coils for petroleum casing pipes. The steel comprises the following chemical composition in percentage by weight: 0.14 to 0.21 percent of C, less than or equal to 0.40 percent of Si, 0.8 to 1.4 percent of Mn, 0.015 to 0.050 percent of V, 0.008 to 0.020 percent of Ti, less than or equal to 0.025 percent of P, less than or equal to 0.008 percent of S, 0.015 to 0.050 percent of Alt and the balance of iron and inevitable impurity elements. The invention has the advantage that: high-quality low-cost steel for J55-grade petroleum casing pipes can be stably produced on a large scale.