Method for Improving Residual Stress of Structure Member

摘要

A method for improving residual stress of a structure member, comprising steps of: disposing coolant vessels around a pipe being the structure member at an upstream position and a downstream position of a welded portion of the pipe; wrapping a heat insulation member around an outer periphery of the pipe at a center portion in an axial direction of the pipe in each of the coolant vessels; forming the ice plug in the pipe at each position disposing the coolant vessels by cooling an outer surface of the pipe wrapping the heat insulation member in the coolant vessels; and freezing water between the ice plugs in the pipe by cooling the outer surface of the pipe between the ice plugs.