Modelling approach for quantitative prediction of macroshrinkage and microshrinkage in A356 sand mould castings

Abstract

An advanced casting simulation based optimisation approach was applied in this study to assist in the improvement of the mould design of aerospace components made of A356 alloy. By using this approach, mould filling and solidification related defects (including macroshrinkage and shrinkage porosity) were significantly minimised and hence it helped in cost reduction, performance enhancement and quality assurance of complex A356 cast parts. An experimental validation and detailed calibration procedures of the models for prediction of macroshrinkage and shrinkage porosities were performed using A356 plates cast in furan–silica sand moulds using the Prometal rapid casting technology (RCT) mould printing technology. Correlations between Niyama values and the pore percentage were also developed. Therefore, the severity level of shrinkage porosity can be determined via the Niyama criterion. Predictions were then compared with the macroshrinkage and porosity measurements in plates of various plate thicknesses and in other commercial A356 casting components.

Keywords:

• Furan–silica sand mould plate castings
• A356 alloy
• Solidification
• Macroshrinkage
• Microshrinkage
• CFD model validation and calibration

The author would like to acknowledge ExOne/Prometal RCT (Dan Maas and Mihaela Nastac) for their continuous support and useful comments and suggestions in developing this article.