| 摘要 |
PURPOSE:To prevent thickness deviation and streak and to improve quality by elongating a rolled hollow stock with the roll roll-fitted to the outer periphery of a rolled stock with supporting a plug by its tip side and base end side. CONSTITUTION:The other end part of a core metal 4 and a rotary joint 6d are linked and a tensile force applying device 6 is driven to give specific load on core metals 3, 4 and a plug 2. In this state, a roll 1 is driven and a rolled stock P is fed to perform elongation rolling. By this method, the generation of a spiral streak and thickness deviation is prevented and the product of good inner part quality and good dimensional accuracy may be obtd.
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