Hot corrosion studies on dissimilar friction welded low alloy steel and austenitic stainless steel under chlorine containing salt deposits under cyclic conditions

High temperature corrosion tests were performed on dissimilar friction weldment of low alloy steel and austenitic stainless steel. Test conditions simulated the environment of a biofuel fired boiler. The samples were exposed to synthetic salt containing 40 wt-%K2SO4, 40 wt-%Na2SO4, 10 wt-%KCl and 10 wt-%NaCl. In the present paper, hot corrosion behaviour of friction welded AISI 4140 and AISI 304 dissimilar materials in molten salt environments at 500, 550 and 600 degrees C was studied. Corrosion was extremely severe on the interface of the dissimilar weldment in molten salt environment. Comparative evaluation was based on the effect of burn-off length and temperature of exposure on hot corrosion behaviour of the dissimilar weldment. Even the interface was attacked through chromium rich phases in hot corrosion environment. The metals formed on the weldment were non-protective.