Method and apparatus for increasing thickness of tubular member

摘要

A method and apparatus for increasing a thickness of a tubular member which ensures a uniform thickness increase of the tubular member and a reduction of an increase in a thickness on an inner diameter side of the tubular member. A portion of the tubular member is subjected to upsetting by applying thereto a compressive force in an axial direction of the tubular member, while the portion is being heated locally and progressively so that a surface layer of the portion of the tubular member reaches a high temperature and a thermal gradient is generated between inner and outer diameter portions of the tubular member. A loading arrangement is provided which is adapted to apply a compressive force in the tubular member in an axial direction thereof, with an annular heater being arranged around an outer circumference of the tubular member. The annular heater is capable of being moved in an axial direction of the tubular member and a control device is provided for controlling a temperature of the heater.