| 摘要 |
<p>Disclosed are a steel sheet for a line pipe and a manufacturing method thereof, wherein the steel sheet for a line pipe can have a property of a low yield ratio and secure a high workability and the high deformability of a pipe through an allow element control and a process condition control. The manufacturing method of the steel sheet for a line pipe according to the present invention comprises: a step of reheating a slab sheet; a step of firstly rolling the reheated sheet in an austenite recrystallization area; a step of secondly rolling the firstly rolled sheet under the condition of a finish rolling temperature (FRT) of 860 to 890°C; and a step of cooling the secondly rolled sheet under the condition of a finish cooling temperature (FCT) of 450 to 600°C, wherein the slab sheet comprises 0.05 to 0.15 wt% of C, 0.15 to 0.35 wt% of Si, 1.4 to 1.6 wt% of Mn, at most 0.015 wt% of P, at most 0.003 wt% of S, 0.04 to 0.06 wt% of Nb, 0.05 to 0.10 wt% of Mo, 0.005 to 0.020 wt% of Ti, 0.02 to 0.06 wt% of V, and remnants Fe and other inevitable impurities. [Reference numerals] (AA) Start; (BB) End; (S110) Reheat a slab (SRT: 1150~1250°C); (S120) Firstly roll; (S130) Secondly roll (FRT: 860~890°C); (S140) Cool (FCT: 450~650°C)</p> |
