| 摘要 |
PURPOSE:To suppress the fin over filling generated at the ends of a stock pipe and to improve the yield of rolling by adjusting the inter-flange space of a rolling roll pair of a stand adjacent to the final stand to zero and forming the roll caliber of the final stand to a flat shape. CONSTITUTION:The inter-flange space of the rolling roll pair 20 in the stand adjacent to the upper stream of the final stand is adjusted to approximately zero to decrease the width of the generated fin over filling parts 12 at the time of rolling a hollow stock pipe by using a mandrel mill. The over filling parts 12 are leveled off by the roll pair 30 provided with a flat roll shape of the final stand to suppress the fin over filling at the final end of the shell stock pipe 8. The shell stock pipe 8 is, therefore, rollable by the next stretch reducer without discarding the final end of thereof. |
