| 摘要 |
PURPOSE: A steel sheet for a line pipe and a manufacturing method thereof are provided to secure a steel sheet with superior hydrogen induced cracking resistance by optimizing the component ratio of chrome and other alloys except copper and controlling processing conditions. CONSTITUTION: A steel sheet for a line pipe comprises carbon of 0.03-0.05 weight%, silicon of 0.2-0.3 weight%, manganese of 0.5-1.3weight%, phosphorus of 0.010 weight% or less, sulfur of 0.005weight% or less, aluminum of 0.02-0.05 weight%, nickel of 0.2-0.5 weight%, chrome of 0.2-0.3 weight%, niobium of 0.03-0.05 weight%, vanadium of 0.02-0.05 weight%, titanium of 0.01-0.02 weight%, calcium of 0.001-0.004 weight%, and iron and inevitable impurities of the remaining amount. The steel sheet has a tension resistance of 450MPa or greater. A method for manufacturing the steel sheet comprises a slab reheating step(S110), a hot-rolling step(S120), and a cooling step(S130).
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