Evaluation of the use of foundry sand cores on solidification and on the characteristics of structural castings: a comparison between organic and inorganic cores and validation with simulation

In recent years, the interest in more sustainable and green production has led to searching for new processes and materials to be used especially in foundries. An example is given by the increasing use of inorganic cores instead of organic ones to produce complex and structural aluminum alloy components. The great advantage is related to the reduction of the emissions of toxic substances (such as formaldehyde and phenol), making the working environment healthier. Despite this, the information about the characteristics of this type of materials with inorganic binders is still very low. For this reason, this paper aims at characterizing inorganic cores, especially evaluating the thermal properties of these materials and estimating how they exchange heat with aluminum. Additionally, a comparison between the inorganic and organic sand cores was done in terms of thermal properties. Moreover, in order to evaluate their influences on the alloy solidification and, consequently, on the quality of the casting, properties obtained from the components made with the two different sand cores were analyzed by hardness and tensile tests as well as microstructural analysis. Finally, the measured thermal properties of the inorganic cores were implemented in the casting simulation software ProCAST®. The good agreement between the simulation and the experimental data demonstrated how it is important to know the correct properties of the inorganic sand cores and, in general, the accurate data of the materials to obtain reliable output.