Hot Corrosion Behaviour of Dissimilar Weldments

Dissimilar-metal joints are used widely in various industrial applications due to both technical and economic reasons. The materials used for high temperature applications are subjected to hot corrosion and high temperature wear.The present work deals with to evaluate the behaviour of un-welded and dissimilar weldments of AISI 304 steel and 20MnMoNi55 steel made by TIG welding at temperature 900°C, samples when exposed to high temperature oxidation in air and molten 75%wt sodium sulphate + 25%wt potassium sulphate salt under cyclic condition. Compare the oxidation and hot corrosion performance of the un-welded steel with dissimilar weldments sample and evaluate its suitability for using in boiler applications. The experiments are conduct in laboratory under cyclic condition and after high temperature oxidation,hot corrosion studies were characterized by the techniques such as XRD, SEM/EDAX and X-ray mapping to know an insight corrosion mechanism based on morphology of the corroded products formed on the un-welded and dissimilar weldments sample.The result shows that corrosion resistance is in order of AISI304-DSW- 20MnMoNi55 in both air as well as in molten salt environment.