Investigations into the tendency to stress corrosion of joints welded in austenitic and duplex steels |
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Authors: | J Labanowski K Krzysztofowicz K Samson |
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Affiliation: | Department of Materials Engineering , Gdansk Polytechnic |
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Abstract: | 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 the vessel wall, it is necessary to evaluate the residual stress distribution around the weld fusion line, which 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 the 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. |
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Keywords: | reactor pressure vessel weld-overlay cladding post-weld heat treatment weld residual stress sectioning method deep hole drilling method finite element method thermal-elastic-creep analysis |
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