Hot corrosion appears in the super-heater pipes in operation under severe conditions. This is one of the most common forms of corrosion found in high-temperature environments. In this investigation, hot AO corrosion of dissimilar welded joints of super heater pipes (5.5 mm thickness) namely SA335 P91 and SA218 P22 (good oxidation and corrosion resistance) are evaluated. Suitable weld process like PCGTAW, where low heat input makes high-quality welds with very good resistance to corrosion were employed. E70S2 filler is employed to join these bimetallic, which is often found widely in practice. Micrographs from the optical microscopy was used to reveal the microstructure of these weldments. The performances of the weldments have been ascertained by exposing the welded coupons in the cyclic AO at 700 ℃ for 50 cycles. Thermogravimetric plots were established to find the corrosion kinetics. The growth of the oxide layer formed on the weldments and HAZ have been systematically characterized by using techniques like SEM combined with EDS and XRD. The study assimilated that all the coupons exhibited better Oxidation resistance. Spallation of oxide scale was experienced at the weld zone.