| 摘要 |
<p>PURPOSE:To uniformize the thickness of a rolled tube stock and to improve the finishing dimensional accuracy by equalizing a ratio of a rolled stock width Xa rolling length between rolling stands, being at optionally selected positions, of a seamless steel tube mandrel type rolling mill to the target ratio. CONSTITUTION:Rolled stock width signals from width measuring instruments 8, 9 and speed (rolling length) signals by a rolling roll peripheral speed measuring instruments 11 at rolling stands ST2 and ST3, being at optionally selected two positions, of a seamless steel tube mandrel type rolling mill are sent to a stock width measuring monitor 7 and a rolling speed monitor 12, respectively. A ratio of rolled stock width X a rolling speed (rolling length) between rolling stands ST1 and ST2 is inputted into a rolling speed controller 13 and is compared with the target ratio from a rolling specification decision device 15. According to deviations between the above two ratios, either rolling roll speed of the stands St1 and ST2 is variably controlled 16. The thickness of a rolled stock 2 is kept to be uniform and the finishing dimensional accuracy is improved. It is allowable to set an analogous value of a square function of a ratio of rolled tube stock sectional areas before and after rolling as the target ratio of a speed ratio.</p> |
