Prediction of Microstructure and Porosity Formation of Practical Spheroidal Graphite Iron Castings

The mathematical model for microstructure formation and porosity prediction during solidification process of SG iron casting was established and applied to a practical brake housing casting. Quantitative microstructure analysis of specimens machined from the castings was compared with the simulation, and the two results are in acceptable agreement on nodule counts and size, pearlite fractions and hardness. It is indicated that the model can calculate the fraction of ferrite and pearlite more accurately, and specially can reflect the effect of both under-cooling during solidification and the nodules formed in eutectic period on the pearlite content. The present porosity prediction was compared with those of a former method and commercial software, which leads to that the current methods used for porosity prediction should be investigated and improved further.