Microstructural and electrochemical characterization of a thin-section dissimilar stainless steel weld joint

A dissimilar weld joint consisting of an austenitic stainless steel (ASS) and a martensitic stainless steel (MSS) was obtained under optimized welding conditions by autogenous gas tungsten arc welding technique. The weld metal was found to be dual-phased, and was constituted with an austenite matrix containing interdendritic ferrite of about 3-8 EFN, with over-matching mechanical properties. Electrochemical behaviour assessment of the composite zone comprising the weld metal, HAZ of both ASS and MSS showed different general corrosion behaviour in neutral and acidic chloride solutions. However, in both the electrolytes, the pitting susceptibility of this region was the highest, and the MSSHAZ of this composite zone was the observed to be more vulnerable to localized damage.