| 摘要 |
PURPOSE:To obtain the product of good dimensional accuracy that the cross sectional shape of the product is close to a complete roundness by arranging the mill roll of adjoining stands by changing it by the specified angle in the peripheral direction of a pipe. CONSTITUTION:A stretch reducing mill 1 is arranged in 20 sets of No.1-No.20 stands toward the downstream side from the upperstream side in the pipe progressing direction. The mill roll 4a, 4b, 4c of No.4, No.8, No.12, No.16 and No.20 stands and the mill roll 4a, 4b, 4c of No.1, No.5, No.9, No.13, No.17 stands are arranged by sliding the angle in the peripheral direction of the pipe which is formed by 30 deg. in counterclockwise direction similar to the case of other stands. In this way the product close to complete roundness and good in dimensional accuracy is obtainable because of being smaller than the conventional 60 deg.. |
