著者

宇田川 誠 勝山 仁哉 西川 弘之 鬼沢 邦雄

出版者

一般社団法人 溶接学会

雑誌

溶接学会論文集 (ISSN:02884771)

巻号頁・発行日

vol.28, no.3, pp.261-271, 2010 (Released:2010-07-29)

参考文献数

19

被引用文献数

2

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Austenitic stainless steel is welded as a cladding on the inner surface of a reactor pressure vessel (RPV) made of low alloy steel. In order to assess the structural integrity of the RPV precisely, the residual stress distribution caused by weld-overlay cladding and post-weld heat treatment (PWHT) is evaluated. Since the cladding layer is very thin compared to vessel wall, it is necessary to evaluate the residual stress distribution around the weld fusion line can be very steep. In this study, cladded specimens were fabricated using different welding methods. Residual stress measurements using both sectioning and deep hole drilling (DHD) methods were then performed to evaluate the residual stress distributions through the weld fusion line. Three-dimensional thermal-elastic-plastic-creep analyses based on finite element method were also conducted to evaluate the residual stress caused by weld-overlay cladding and PWHT. It was shown that analytical results provided reasonable agreements on weld residual stress with experimental results. It was also clarified that the main cause of residual stress due to welding and PWHT was the difference of thermal expansion between weld and base metals.

著者

山口 義仁 勝山 仁哉 李 銀生 西山 裕孝 鬼沢 邦雄 土居 博昭

出版者

一般社団法人日本機械学会

雑誌

M&M材料力学カンファレンス

巻号頁・発行日

vol.2014, pp."OS0807-1"-"OS0807-3", 2014-07-19

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In recent years, Japanese nuclear power plants experienced multiple large earthquakes. It is very important to assess the seismic safety of piping taken the occurrence of such a large earthquake into account, when a crack exists in pipe welding joint. One of the key issues is the effect of excessive loading in the seismic response wave on the fatigue crack growth behaviour. We performed fatigue crack growth tests under constant amplitude cyclic loading with a single excessive tensile/compressive load for Ni-based alloy weld metal. Acceleration and retardation was confirmed in crack growth due to the excessive loading. The stress distribution in front of crack tip and the shape of crack tip were investigated to clarify the cause of changes of crack growth rate. A crack growth evaluation method has been proposed considering the effects of the excessive loading based on the variation of the stress distribution in front of crack tip and the crack blunting. The predicted crack growth rate by the proposed method was in good agreement with the experimental ones.