| 摘要 |
<p>The present invention relates to a hot-rolled steel sheet for a steel pipe comprising: 0.03-0.1 wt% of C, 0.01-0.50 wt% of Si, 1.2-2.5 wt% of Mn, 0.002 wt% or less of S, 0.03 wt% or less of P, 0.01-0.10 wt% of Ti, 0.01 wt% or less of N, 0.01-0.13 wt% of Nb, 0.1-0.5 wt% of Ni, 0.1-0.5 wt% of Mo, 0.01-0.5 wt% of Cr, 0.002 wt% or less of B, and the remainder consisting of Fe and inevitable impurities; and to a manufacturing method thereof. The elements of the hot-rolled steel sheet for a steel pipe satisfy a formula (1) to a formula (3). Fine structure thereof comprises 60-80% of acicular ferrite and 20-40% of granular bainite with respect to the total area.</p> |
