SiC-The Most Efficient Addition to Increase the Nodule Count in Ductile Iron

Abstract

In the first phase of the AFS-sponsored research project on “Restoring Techniques for “Monday Morning Iron”, the investigation focused on the extent to which prolonged holding of the base iron in an induction furnace affected the quality of ductile iron. The objective in Phase II was to find a way to increase the nucleation potential of iron having a high chilling tendency. The technique consisted of adding SiC, SiCa, crystalline graphite, etc., to a base iron in the furnace before the Mg-treatment with the aim to supply the iron with active elements considered suitable sites for graphite nodule nucleation. The results of this investigation demonstrated that SiC is the most efficient addition to increase the iron nucleation potential. Based on these results, tests were run under commercial foundry operating conditions. This report presents and discusses the results of investigation performed in the MTL laboratory with detailed analysis of chilling tendency, microstructure and shrinkage propensity on test samples from both base and final ductile irons.