High Temperature Oxidation and Hot Corrosion Behavior of T92 Bare Steel Weldments and in Na2SO4-60%V2O5 Molten Salt Environment at 900°C

Abstract

Hot corrosion is a serious problem in power plant, petro-chemical and marine applications where the weldments are usually subjected to aggressive corrosion environment. So the hot corrosion behavior has become main focus of the proposed work. High temperature oxidation and hot corrosion investigation has been carried out on SA213 T92 boiler steel weldment at the temperature of 9000C under cyclic condition for 50 cycles. Each cycle consisted of 1 hour heating at 900°C followed by 20 min of cooling in air. The experiment was conducted air as well as molten salt (40wt.% Na2SO4 + 60wt.%V2O5) environment. Comparison has been made between high temperature oxidation and hot corrosion performance of weldments to evaluate its suitability for using its boiler applications. Thermogravimetric technique was used to establish kinetics of corrosion. The result shows that the cyclic hot corrosion of weldment in salt environment follows parabolic law. X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive X-ray (SEM/EDAX) techniques were used to characterize the oxide scales.