| 摘要 |
<p>The present invention provides a hot coil for a line pipe with which variation in the room temperature strength is reduced and low-temperature toughness is improved even with a hot coil for which there are many restrictions on the manufacturing conditions in the winding process, and provides a method for manufacturing said hot coil. A steel plate is held for a prescribed time between each rolling pass in the recrystallization temperature range, and a two-stage cooling is performed after hot rolling, thereby providing the steel structure of the center of the plate thickness with an effective crystal grain diameter of 3-10 μm and a total area ratio of bainite and acicular ferrite of 60-99% and, when the total area ratio of bainite and acicular ferrite for two given locations respectively are A and B, with the absolute value of A-B being 0-30%.</p> |
