| 摘要 |
PURPOSE:To quench the peripheral face in a tube and to heighten its hardness in a process that bends a tube to be worked by pulling while heating the tube by a high frequency coil and quickly cools the tube by cooling water by performing above-mentioned heating and cooling from the inside of the tube. CONSTITUTION:The tube to be worked 1 is lifted up and fitted from the outside concentrically to a conduit 3. A cooling water injection nozzle 4 and a high frequency heating coil 5 are provided at a lower end of the conduit 3. An arm 7 freely rotatable around a pivot 8 is connected to an end of the tube 1 by actuating a clamping cylinder 9. The lower end of the tube 1 is heated by energizing the coil 5, and a wire rope 21 is wound to pull down the tube 1 by actuating two winches 19. Thus, the tube 1 is bent around the axis 8 while setting a lower reference roller 10 as a base. At the same time, cooling water is jetted from the nozzle 4 to the inner peripheral face of the tube 1 to perform quick cooling. |
