| 摘要 |
PURPOSE:To manufacture a twisted deformed pipe, with different sectional diameters without using a core bar at the time of manufacturing a twisted tapered pipe, etc., by spinning from a hollow cylindrical pipe material by using a roll formed into a wavy or polygonal peripheral surface of the forming roll. CONSTITUTION:The forming roll 2 is touched at the position to be drawn into the minimum diameter, the forming roll 2 is pushed down to drawn into prescribed outer diameter while rotating the pipe material 1 by a driving chuck 5. At this time, when a pressure is applied on the stress applying side of the chuck 6, the wall thickness of the minimum diameter part is not thinned thereby. Then, in the case of tapering work while moving the forming roll 2 in the right direction and lifting up its position, a tensile force is loaded on the pipe material 1, the forming is performed without thickening the wall thickness thereby.
|
