Computation and application of local solidification times of grey cast iron cast in metallic moulds

Heat conduction equations applicable to the solidification of grey cast iron cast in moulds of the same material were solved for the cases of plate and cylindrical shaped castings made by pouring the metal at different temperatures into moulds of different wall thicknesses preheated to different temperatures, when the heat transfer coefficient at the casting-mould interface was assumed to have different values. An explicit finite difference method was used to solve the equations with the aid of a digital computer. Local solidification times at different nodal points were determined from the solutions and a relationship between the local solidification time and the location in a ‘casting’ was established. The application of local solidification times for predicting the microstructure and estimating the ultimate tensile strength of these “castings” cast in metallic moulds has been demonstrated.