Duplex stainless steels are used typically in approximately equal volume fraction of ferrite and austenite phases to offer the favorable properties of both phases(1). Subjecting to thermal cycles like welding could change this balance and microstructure, affecting the corrosion resistance(2). After Brigham who introduced critical pitting temperature (CPT) as a temperature below which there is no stable pit(3), many researchers have used CPT as a criterion to rank pitting susceptibility in stainless steels(4). The influence of different ions on CPT has been investigated and further studies, corresponds the shift in CPT values to Change in pit chemistry (5), however the effect of microstructure on the pit chemistry has not been studied yet. The aim of this work is to study the effect of microstructural changes due to various solution annealing temperatures on CPT. Mechanistic approach has been done by focusing on the effect of microstructural changes on diffusion limiting current density (ilim) of duplex stainless steels.

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