| 摘要 |
PURPOSE:To prevent deformation of a bend part due to working, also to reform a deformed external form and to execute forming properly, by insert-fitting a high frequency heating inductor and a cooling device in a metallic pipe, installing a forming roll on the outside face of the metallic pipe, and executing the bend-working. CONSTITUTION:Heating is performed to a hot plastic workable temperature by an inductor 2 from the inside face of a metallic pipe 1, and immediately after that, a coolant is blown to the inside surface of the pipe 1 from a nozzle 3 provided on the tip of the inductor 2, and a heating area is adjusted. Subsequently, a forming roll 5 for preventing the deformation is made to press-contact with the outside surface of the pipe 1, one end part of the pipe 1 is pushed by a pushing device 7, the other end part is bent by a rotating arm 6, a bending moment is provided to a bend-working area (plastic deforming area), and the pipe 1 is bend-worked. In this case, the pipe 1 is fitted into a space of a proper shape constituted of a groove 51 of the roll 5, and accordingly becomes in a state that it is fitted into a die and is worked, therefore, the bend part is also formed to a desired shape. In this way, conversion to an oval of the bend part, wrinkles and other deformation are prevented exactly, and even if deformation is generated in the plastic area, it is reformed by the roll immediately. |
