Residual stress improvement method by high frequency induction heating method

摘要

PPROBLEM TO BE SOLVED: To provide a method for sufficiently reducing a residual stress of such a portion as a decontamination port of a pipe in a recirculation system, at which a non-condensable gas stays. PSOLUTION: This method for reducing the residual stress comprises the steps of: substituting vapor for the non-condensable gas which stays at the part to be executed to discharge the non-condensable gas from the inside of the part; further substituting water for the vapor which has substituted for the gas in the part; and then heating an outer surface of the part in a state of having filled the part with the water to generate temperature difference in a thickness direction of the part. The method can remove the non-condensable gas, and accordingly can sufficiently reduce the residual stress in the part at which the non-condensable gas stays. PCOPYRIGHT: (C)2007,JPO&INPIT