Study on the role of solution treatment on corrosion behavior of duplex lightweight steel in different environments

Abstract

Diverse microstructure and complex application environments increases the uncertainty of the corrosion resistance of lightweight steels. The effect of solution treatment on the corrosion behavior of Fe–16Mn–10Al–1.5C–0.1Ti lightweight steel in Cl−, HSO3− and Cl−–HSO3− environments was investigated using electrochemical measurement, scanning electron microscope (SEM) and X–ray photoelectron spectroscopy (XPS). The lightweight steels are dominated by austenite and contain a small amount of ferrite. The increase in solution treatment temperature leads to more ferrite formation, but it has less effect on grain size. The decrease in austenite content results in more corrosion microcells and a porous oxide film; therefore, the corrosion resistance of the steel deteriorates with increasing temperature. In addition, in the Cl−–HSO3− environment, the synergistic effect of Cl− and HSO3− leads to the formation of a weak protective oxide film, resulting in a significant increase in corrosion rate compared to the Cl−and HSO3− environment.