A process model for the microstructure evolution in ductile cast iron: Part II. Applications of the model

In the present investigation, the process model developed in Part I has been implemented in a dedicated numerical code to reveal the evolution of the coupled thermal and microstructural fields during directional solidification of ductile iron. In a calibrated form, the model predicts adequately both the variation in the graphite nodule count and the resulting microstructural profiles (i.e., graphite, iron carbide, ferrite, and pearlite) in the length direction of the bar. At the same time, the model has the required flexibility to serve as a research tool and predict behavior under conditions that have not yet been explored experimentally. In this article, the aptness of the model to alloy design and optimization of melt treatment practice for ductile iron is illustrated in different case studies and numerical examples.