Method of correcting distorted pipe end

摘要

In a method of correcting a distorted pipe end to an original substantially true circular cross-section, external loads are applied to the outer peripheral surface of the pipe adjacent to the end thereof to forcibly deform the pipe end to the substantially true circular cross-section. The external loads are maintained to keep this substantially true circular cross-sectional shape while an internal pressure is applied to the inner peripheral surface of the pipe end until a circumferential stress produced in the pipe reaches an amount which exceeds the yield stress of the pipe to give a radial permanent deformation to the pipe for thereby producing a circumferentially uniformly distributed residual stress in the pipe.