The Effects of MgFeSi and Inoculant Selection on Microstructure and Mechanical Properties of Varying Section Size Ductile Iron Castings

The selection of MgFeSi alloy and inoculants used for ductile iron treatment has confounded members of the foundry industry for many years. Frequently foundries have used certain types of alloys "because they have always done it that way" or "because someone else was doing it." The current study involves ductile iron produced with three grades of MgFeSi with varying levels and types of rare earths along with four different inoculants. The iron was cast into test samples of various thickness from 2x2x8 inches to 10x10x8 inches. Mechanical properties and microstructures were evaluated at multiple locations in each of the 36 samples for a total of 156 points of data. In this paper, we will summarize the findings for differing section sizes.