Interaction of Corundum Non-Stick Coating with Iron-Carbon Melts in the Conditions of Lost Form Casting
The thermodynamic calculations results of interaction of ironCcarbon melts with nonstick coating based on corundum at temperatures of steelmaking processes (1600-1700°C) are presented. The melts of construction steel (steel 10), tool steel (U8) and grey cast iron (SChC15) with oxygen and aluminum content [O] = 0.001%, [Al] = 0.02% respectively have been selected as objects of research. The processes of nonCstick coating dissolution in metal, his deoxidation by melt components (carbon, silicon) and interaction with dissolved oxygen were considered in assessing the interaction of corundum with iron-carbon melts. As a results of calculations boundary aluminum concentration [Al] in melt is determined. The dissolution and deoxidation of corundum is possible above this aluminum concentration in melt. Oxygen transfer in the form of FeO from metal in nonCstick coating with formation of hercynite and liquid slags of the system FeO-Al2O3 is shown to be possible at high oxidation of the melt ([O] > 0.05% at 1600°C). In the process of manufacturing castings by lost formcasting the models made of expanded polystyrene (casting molds) are destructed from melt heat energy with separation gas-vapor mixture (phase). The gasCvapor mixture (phase) is led in supporting material through the pores of non-stick coating. To estimate the effect of this component on non-stick coating the reactions of corundum interaction with the components of the gas-vapor medium are considered.