Gnanamurthy K, Muralidhara B K, Basalalli V K

Abstract: A virtual solidification program based on explicit finite difference method has been developed to study solidification as it progresses in a 3D metal-mold field. The simulation uses Fourier conduction equation in the finite form and special techniques to handle latent heat as well as exothermic behavior of sleeves. Formation of gross shrinkage as may be viewed in a dynamic radiography, and prediction of micro porosity by study of cooling curves and application of Niyama criterion are presented in this work. The results obtained in these solidification studies have been verified with 18-10-3 stainless steel castings poured in sodium silicate molds. While 95\% of results agree, in 5\% of cases, simulation studies do not approve castings marginally cleared by experimental results, making the simulation method a shade safer. The program is user friendly and is carried out in a personal computer or laptop. The foundry man can carry out desk top experiments by changing physical properties or apply non isothermal conditions in metal/mold, use chills, insulating/exothermic sleeves etc to study gross shrinkage or predict micro porosity by thermal analysis on a real time basis and thus promote directional solidification to drive the defects towards the feeder or a non critical zone.

Keywords: Castings, Directional solidification, Micro porosity, Minimize gross, Program, Promote, Virtual solidification