| 摘要 |
<p>PURPOSE:To control the thickness of a steel tube with high accuracy by detecting the thickness of a relaying part with a thickness gage whenever a welded part of a skelp passes the thickness gage and measuring a quantity of tracking delay before the thickness of the relaying part is detected by the change of current value of a roll motor at a control rolling stand. CONSTITUTION:The thickness of the skelp 5 in its longitudinal direction is measured continuously by the thickness gage 10 equipped in front of a heating furnace 15, a measured thickness signal is delayed synchronously with a line speed up to the control rolling stand, the control rolling stand is controlled in accordance with a thickness deviation signal being a difference between this delayed thickness signal and a reference thickness signal to control a thickness variation in the longitudinal direction of the tube. Whenever the skelp 5 and the welded part of the skelp pass the thickness gage 10, the relaying part is detected by the thickness gage to measure the quantity of tracking delay before the relaying part is detected. In this way, since each skelp is corrected by the actual result of tracking, the thickness is measured with high accuracy.</p> |
