Finite Element Analysis of Heat Flow in the Stepped Casting in Evaporative Pattern Casting Process

摘要

The Evaporative Pattern Casting (EPC) process uses expandable polystyrene as the pattern. The pattern is enclosed in a one-piece sand mould, with no bonding material. As the metal is poured, the pattern vaporises, and the metal takes its place. This paper presents finite element modelling of heat flow in stepped casting in EPC process and the same is used to evaluate the effect of heat on the different sections in the casting. All FEM analyses were performed using a commercial finite element package ANSYS 7. The analysis of results indicates that the heat transfer is high in thin section of castings due to large thermal gradient. Temperature at the thin section of the casting changes very fast. The density of heat flux vectors is high at thin and outer corners. Cooling in thin section is higher than the cooling in section of medium thickness and similarly, cooling at section of medium thickness is higher than cooling in thick section. So, solidification starts from those interface regions where cooling rate is high.