WORKING METHOD FOR DEFORMING SECTIONAL SHAPE OF METALLIC PIPE IN LONGITUDINAL DIRECTION INTO SIMILAR SHAPE

摘要

PURPOSE:To deform the sectional shape of a metallic pipe in the longitudinal direction thereof into a similar shape by fixing one end of the metallic pipe, pulling the other end thereof to the axial direction and subjecting continuously the pipe to plastic deformation and cooling by induction heating. CONSTITUTION:One end 1' of a metallic pipe 1 having a circular section is fixed to a stationary chuck 2 and the other end 1'' is pulled in the direction of an arrow A by a chucking device 4 for pulling which is movable on a slide rail 3. The outside circumferential part (a) in the diametral direction of the pipe 1 is heated in this state by induction current conducting in a coil 5 for induction heating. Said part is softened by heating and is deformed plastically by the pulling force to have the smaller diameter. The deformed part (b) is cooled by the compressed air or the like blown from a cooler 6 adjacent to the coil 5 so that the section thereof is deformed similarly to the section of a small diameter pipe. The section of the metallic pipe is continuously deformed in the longitudinal direction into a similar shape by the simple device without using dies. The method is usable for the pipe material having not only a circular but square shape as well.