| 摘要 |
PURPOSE:To increase thickness uniformly without irregular deformation, by heating successively and locally a thickness increase-working part of a pipe, compressing the pipe at a constant speed in the axial direction, and executing the compression under a narrowed deforming area of the pipe by local heating. CONSTITUTION:A thickness increase-working device is constituted of a stepping cylinder 6 for compressing a pipe 1 at a constant speed in the axial direction by a spindle 7, and a ring-like heating coil 13 which is placed so as to be positioned in the outside circumference of the pipe 1 and can move along the axial direction of the pipe. In this state, when executing the thickness increase-working of the pipe, the thickness increase-working part of the pipe 1 is heated locally, its heating position is moved successively along the axial direction of the pipe 1, compressive force for compressing the pipe 1 at a constant speed is loaded by the stepping cylinder 6, and also the deforming area of the pipe by compressive force is narrowed by local heating of the heating coil 13, by which irregular deformation is prevented. |
