Geometrical and welding conditions on through-thickness residual stress in primary piping of girth welded joints

一次系配管の周溶接部における残留応力に及ぼす形状及び溶接条件の影響

勝山 仁哉  ; 望月 正人*; 森 裕章*; 浅野 航*; An, G. B.*; 豊田 政男*

Katsuyama, Jinya; Mochizuki, Masahito*; Mori, Hiroaki*; Asano, Wataru*; An, G. B.*; Toyoda, Masao*

近年、ステンレス鋼製の一次系配管において応力腐食割れ(SCC)が顕在化している。SCCは溶接により生じる引張残留応力に起因し発生・進展すると考えられる。本研究では、三次元及び軸対称有限要素解析を用いて、配管形状及び溶接条件が板厚内の残留応力に及ぼす影響について評価した。対象はSUS316Lステンレス鋼配管の突合せ溶接部とした。三次元及び軸対称モデルによる残留応力を詳細に比較し、配管形状及び溶接条件の影響について検討を行った。

Recently, stress corrosion cracking (SCC) of primary piping of stainless steel has been observed. SCC is considered to initiate and progress at near the welding zone in butt-welded pipes, because of the tensile residual stress introduced by welding. In present work, three-dimensional and axisymmetric thermo-elastic-plastic finite element analyses have been carried out, in order to clarify the effect of geometrical and welding conditions on through-thickness residual stress. In particular, butt-welding joints of SUS316L pipes have been examined. The residual stress was simulated by three-dimensional and axisymmetric models and the results were compared and discussed in detail.