Experimental and CFD Modeling of the Degree of Eutectic Modification in A356 Silica Sand and Metal-Mold Castings

A computational fluid dynamics (CFD) casting simulation-based optimization approach previously developed was applied in this study to assist in the improvement of the mold process design of sand and metal cast components made of A356 modified alloy.  By using this approach, the degree of eutectic modification was properly controlled and hence it helped in cost reduction, performance enhancement and quality assurance of complex A356 cast parts.

An experimental validation and detailed calibration and verification procedures of the model for prediction of the degree of eutectic modification were performed using A356 cylinders cast in no-bake silica sand molds and in metal molds. Correlations between the solidification modulus and the eutectic modification values were developed.  Thus, the level of shrinkage porosity and pore dimensions can be estimated by using the developed modification criterion.  Predictions were then compared with the modification measurements in cylinders of various diameters and in other commercial A356 casting components. The predictions were in good agreement with the experimental measurements.