| 摘要 |
PURPOSE:To prevent surely the generation of a sticker phenomenon in the stage of pushing a blank material into a piercing mill for producing a seamless steel pipe by applying beforehand rotation to the blank material. CONSTITUTION:A blank material 14 heated to a prescribed temp. is transferred onto rolls 20 of a preliminary rotation device. The material 14 is beforehand rotated with the rolls 20 which are rotated by the operation of a motor 22 and is transferred by a pusher 15 in the direction of main rolls 11. The material 14 is thus bitten into the rolls 11 in the state of being rotated beforehand in the same direction as the rotating direction of piercing and is pierced by the rolls 11 and a plug 13. The generation of a biting defect known as a sticker phenomenon is surely prevented. |
