| 摘要 |
<p>PURPOSE:To improve the control accuracy of the outer diameter of pipe by previously obtaining the variation pattern of the outer diameter for obtaining a target outer diameter for each material and wall thickness, etc. of a pipe stock and adjusting a roll gap for obtaining this target, in rolling stage. CONSTITUTION:Temperature patterns from the top of a pipe stock H to its bottom are prepared for each of the items of the wall thickness, the wall-thickness deviation, and/or the surface properties of pipe stock H. And the temperature pattern of pipe stock H is previously selected to obtain the target outer diameter in hot rolling at each part of the axial direction. In rolling the pipe stock H, a roll gap with respect to the axial direction of pipe stock H is controlled based on a rolling load and a mill rigidity factor. Then the pipe stock H is rolled by passing it through plural stands 1-7 provided with caliber rolls, to conform the outer diameter of pipe H' to the target value.</p> |
