| 摘要 |
<p>PURPOSE:To prevent the generation of bulging by reducing a roll gap at the time of rolling both ends of a pipe material and controlling also the number of revolutions of rolls so as to provide an additional tension to the longitudinal direction of the pipe material. CONSTITUTION:7 to 9 sets of stands 2 consisting each of a pair of caliber rolls are arranged continuously in a single row, and a pipe stock 1 having a mandrel bar 4, inserted into it, is passed through the row of stands 2 to reduce its wall thickness by elongation. The roll axes of adjoining stands 2 of this mill are arranged by making them intersect at right angles to each other. And roll gaps are reduced at the time of rolling both ends of the pipe stock 1, and at the same time, the number of revolutions of the rolls are controlled so as to provide an additional tension to the longitudinal direction of the pipe 1.</p> |
