Corrosion behavior of valve steels in oxidizing atmosphere containing acetic acid

Abstract

The oxidation kinetics of X33CrNiMn23-8 and X50CrMnNiNbN21-9 valve steels have been studied in oxidizing atmosphere, containing 49.5% of water vapor and 0.5% of acetic acid in the temperature range 1073-1273 K. It has been found that the mechanism of corrosion under these conditions is rather complex. After early stages of the reaction, lasting between 20 and 40 hours, the process follows approximately parabolic kinetics. It has been found that the presence of acetic acid highly increases corrosion rate of X33CrNiMn23-8 steel, containing rather high chromium content, but has no influence on the corrosion rate of X50CrMnNiNbN21-9 steel with lower chromium concentration.