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

• Main Authors: TAKAYANAGI TSUNEO, AOIKE SATOSHI, HISATSUNE SHINICHI, HIDAKA AKITAKA, IWAMATSU FUMINORI
• Format: Patent
• Language: English; Japanese
• Published: 16.05.2016
• Subjects: CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

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 【課題】互いに離れて位置する複数の溶接部を有する配管の引張残留応力を簡易かつ短時間で低減させることが可能な技術を提供する【解決手段】複数の配管部材１１と、複数の配管部材１１を互いに突き合わせて溶接して形成された複数の突合せ溶接部１２とを備える配管１０の引張残留応力改善方法であって、配管１０の内部に水を保有させた状態で、配管１０の両端に位置する配管部材１１Ａ，１１Ｂの内部に氷栓２３を形成して、配管１０内部に水密な空間２４を形成する。水密な空間２４を形成後に、水密な空間２４に対し不凍液２５を供給し、水密な空間２４の内圧を上昇させ、各配管部材１１の突合せ溶接部１２の近傍部を塑性変形させて拡管する。【選択図】図１