LAUSR

Abstract A novel bipolar electrochemistry screening method to reveal corrosion susceptibility of weld microstructures is introduced. This metallographic method is applied to characterise the weld microstructure of a lean duplex stainless steel. The corrosion behaviour of the Fusion Zone (FZ), Heat Affected Zone (HAZ) and Base Metal (BM) was revealed, with the most severe etch response found at the interface between Fusion Zone (FZ) – Heat Affected Zone (HAZ). Transpassive and crevice corrosion were more significant in the FZ, with the highest corrosion resistance observed in the BM. The observed behaviour was linked to differences in local element distributions and the ferrite-to-austenite phase fraction. Corrosion pits formed via preferential dissolution of the ferrite, with the austenite preferentially dissolving in the transpassive region.