And residual stress method for improving the piping, the construction management method

摘要

PPROBLEM TO BE SOLVED: To provide a method for compressing a tensile residual stress working on an inner surface in the vicinity of a pipe welded part at a 350°C construction temperature. PSOLUTION: A step is repeated at least twice, wherein, after heating the vicinity of the pipe welded part at the 350°C construction temperature by heater heating from the outer surface, cooling water is supplied to the pipe inside to rapidly cool the inner surface. In the construction management, a temperature difference between inner and outer surfaces is evaluated based on lowering speed of the outer surface temperature when the cooling water is supplied to rapidly cool the inner surface, and on a pipe plate thickness at a temperature measuring position, and it is confirmed that a thermal stress generated by the temperature difference between the inner and outer surfaces is equal to or higher than a yield stress of a pipe material. PCOPYRIGHT: (C)2012,JPO&INPIT