The variables affecting corrosion and mass transfer of steels by inhibited liquid Bi are discussed and explained in terms of the variables affecting formation of the ZrN or ZrC inhibiting films. Corrosion is acclerated by increasing the maximum temperature of operation, the temperature differential, and the Cr content of the steel. Low carbon areas also are more sensitive to attack, as are rough surfaces. Segregation in weld areas and their normally low C content may be responsible for preferential weld attack. Formation of the inhibiting nitride and/or carbide films is controlled by the activity and distritribution of N and C in the steel. Minor constituents that influence their activity and distribution may also therefore affect the corrosion resistance. Localized attack is accompanied by Zr deposition, possibly resulting from interaction between the dissolved Zr and carbide particles in the steel. ZrN films may spall, and can reform in the spalled and corroded areas.