The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700℃ A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was evaluated by the plane-view and cross-sectional metallography. Experimental results indicate that after certain incubation period, the coated steel was locally attacked, forming hemispherical pits on both CrN and CrN/TiN coated steels. The incubation time for the pit nucleation on the CrN coated steel was shorter than that for the CrN/TiN coated steel. Once the obvious pits formed, the pitted areas increased with dipping time, regardless of the type of coating. After 21 h of dipping, the coating that remai The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN / TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700 ° C A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was evaluated by the plane-view and cross-sectional metallography. Experimental results indicate that after certain incubation period, the coated steel was locally attacked, forming hemispherical pits on both CrN and CrN / TiN coated steels. The incubation time for the pit nucleation on the CrN coated steel was shorter than that for the CrN / TiN coated steel. Once the obvious pits formed, the pitted areas increased with dipping time, regardless of the type of coating. After 21 h of dipping, the coating that remai