| 摘要 |
PURPOSE:To produce a wrinkle-free pipe having exact plural diameters by fixing a die and a plug having plural bearing parts movably in a drawing direction, combining suitably the respective bearing parts and drawing a blank pipe under the grasping pressure. CONSTITUTION:A die 2 having a large bearing diameter d1 and a small bearing diameter d2 is fixed to a support base and is made movable. A plug 4 having a small bearing diameter d3 and a large bearing diameter d4 is provided movably by means of a hydraulic cylinder. The d2 face of the die 2 and the d3 face of the plug 4 are positioned to face to each other and a pipe having the outside diameter d2 and the inside diameter d3 is drawn. The d2 face of the die 2 and the d4 face of the plug 4 are then placed to face to each other and a pipe having the diameter d2 and the diameter d4 is drawn. The d1 face of the die 2 and the d4 face of the plug 4 are placed to face to each other and a pipe having the diameter d1 and the inside diameter d4 is drawn. A pipe 7b having the outside diameters d1, d2 and the inside diameters d3, d4 is thus obtd. |
