PIPING RESIDUAL STRESS IMPROVING METHOD, ANTIFREEZE LIQUID SUPPLY METHOD BETWEEN ICE PLUGS, AND PIPING RESIDUAL STRESS IMPROVING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a technology capable of easily reducing the tensile residual stress of piping having a plurality of separated welded parts within a short time.SOLUTION: The tensile residual stress improving method for piping 10 having a plurality of piping members 11 and a plurality of butting welded parts 12 formed by butting and welding the plurality of piping members 11 forms ice plugs 23 in piping members 11A and 11B located at both ends of the piping 10 in the state of holding water in the piping 10 to form a water-tight space 24 in the piping 10. After the water-tight space 24 has been formed, antifreeze liquid 25 is supplied to the water-tight space 24, the inner pressure of the water-tight space 24 is increased, and the part of each piping member 11 near the butting welded part 12 is plastically deformed to be expanded.SELECTED DRAWING: Figure 1