| 摘要 |
<p>PURPOSE:To obtain products having a high dimensional accuracy by measuring the wall thickness and length of a tube in a hot rolled condition, checking the sufficiency of the target stretching length, and correcting a predected weight of the tube end thickened part of the succeeding tube based on the difference between a calculated weight of a tube end thickened part and the predicted value. CONSTITUTION:When the weight WBM of a billet 20 before rolling is measured by a weighing scale 22, a controlling computer 32 subtracts the predicted weight of a tube end thickened part 10A from the WBM and calculates the target stretching length lT. A wall thickness and length of a tube 10 rolled by a stretch reducer 24 are measured by a wall thickness meter 28 and a length meter 30 in a hot rolled condition. The computer 32 calculates a measured weight of the part 10A based on the above wall thickness profile and checks the sufficiency of the stretch length lT. Then, the predicted weight of the part 10A of the succeeding tube 10 is corrected based on the difference between a measured value and a predicted value of the thickened part 10A. In this method, tubes having a dimensional high accuracy are obtained.</p> |
