Microstructure and intergranular stress corrosion cracking susceptibility of a SA508-52M-316L dissimilar metal weld joint in primary water

Lijin Dong^1,2，Qunjia Peng²，En-Hou Han²，Wei Ke²，Lei Wang¹

1. Key Laboratory for Anisotropy and Texture of Materials,Ministry of Education,Northeastern University2. Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences

摘 要：Correlation of microstructure and intergranular stress corrosion cracking（IGSCC） susceptibility for the SA508-52 M-316 L dissimilar metal weld joint in primary water was investigated by the interrupted slow strain rate tension test following a microstructure characterization.The susceptibility to IGSCC in various regions of the dissimilar metal weld joint was observed to follow the order of Alloy 52 Mb> the heat affected zone of 316 L> the dilution zone of Alloy 52 Mw> Alloy 52 Mw weld metal.The chromiumdepletion at the grain boundary is the dominant factor causing the high IGSCC susceptibility of Alloy52 Mb.However,IGSCC initiation in the heat affected zone of 316 L is attributed to the increase of residual strain adjacent to the grain boundary.In addition,the decrease of chromium content and increase of residual strain adjacent to the grain boundary increase the IGSCC susceptibility of the dilution zone of Alloy 52 Mw.

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