Correlation between the microstructure and corrosion behaviour of copper/316 L stainless-steel dissimilar-metal welded joints

摘要

In this study, the correlation between the microstructure and corrosion behaviour of copper/316 L stainless-steel dissimilar-metal welded joints on an electrolytic copper cathode plate was experimentally investigated. Clear phase separation was noted in the weld metal with the gamma- and epsilon-Cu phase dominating the Fe-rich and Cu-rich zones, respectively. The difference in the corrosion resistance of these zones means that multiple galvanic corrosion couples are formed in different joint areas. Strong galvanic corrosion between the gamma and epsilon-Cu phases caused the shedding of the gamma phase particles from the surface, thereby producing corrosion pits and eventually leading to joint failure.