The corrosion property of three different steels is evaluated in a sweet environment with respect to Mn content and Cr addition. The result shows that high Mn content in steel suppresses the formation of protective FeCO3 scale and it decreases its corrosion resistance in sweet environment. However, addition of 3 wt% Cr improves the stability of the corrosion product formed on high Mn steel. As the immersion time increases, the barrier effect of scale formed on high Mn steel containing 3 wt% Cr becomes better by the formation of both (Cr, Fe)-hydroxide layer and Cr-rich Fe carbonate layer. (C) 2016 The Electrochemical Society. All rights reserved.