Determination of Interface Heat Transfer Coefficient (IHTC) for Investment Casting Simulation- A Sensitivity Study

摘要

Complex shape casting with stringent dimensional accuracy for aerospace requirements is manufactured by investment casting process. One of the main difficulties associated with numerical simulation of solidification processes is the lack of thermo-physical properties and/or boundary conditions. Temperature distributions in investment castings and shells are of great influence on the quality of investment castings. To improve the simulation prediction of casting defects, interface heat transfer coefficient (IHTC) between casting and fused silica shell need to be optimised. Sensitivity study of initial IHTC has been studied and it is observed that initial IHTC = 1000W.m~(-2).K~(-1) need to be assigned in between casting and fused silica shell to predict the thermal profile as well as defects more accurately. Simulation and experimental analysis have been carried out using the optimised IHTC for an austenitic stainless steel investment casting component. Shrinkage porosity location has been compared between simulated and experimental results. The simulated and experimental shrinkage porosity location matches pretty well.