Quantitative prediction of oxide inclusion defects inside the casting and on the walls during cast-filling processes

Oxide inclusions are a common defect in casting production, but their formation and evolution processes are difficult to directly observe experimentally. To accurately predict these, one should calculate the formation rate of the oxide inclusion as well as its wall adhesion. Here, we propose a formation rate model that is relevant to the volume fraction of liquid metal, the temperature, and the current oxide inclusion density. A boundary condition was developed to handle the adhesion and accumulation on the wall; thus, a quantitative indicator is available to directly obtain the,content of the oxide inclusion defects on different parts. We used the open source computational fluid dynamics (CFD) software OpenFOAM to predict oxide inclusion defects inside the casting and on the walls during cast-filling processes. A representative aluminum alloy-casting technology was simulated to analyze the effetts of different runner systems on the oxide inclusion distributions inside casting and on the wall. The simulation results largely coincide with experimental data from the literature. A practical copper alloy-casting technology was then calculated, and the simulation results of the oxide inclusion defects are consistent with the actual casting defect distribution. This confirms the utility of the model. (C) 2017 Elsevier Ltd. All rights reserved.