Dispersion of primary inclusions of Ce2O3 and CeS in Fe-0.20 mass%C-0.02 mass%P alloy

In order to introduce primary inclusions uniformly into a liquid steel, the experiments on the coalescence and separation by flotation of the deoxidation product of Ce2O3 or CeS particles were carried out at 1873 K in an Fe-0.20 mass%C-0.02 mass%P alloy. It was found that the size and number of particles were strongly dependent on the holding time at 1873 K and the cooling rate. The number and size of clusters and those of particles in a cluster in a polished cross-section were metallographically examined. The spatial particle size distribution, which was obtained by applying the Schwartz-Saltykov transformation to the observed planar size distribution, was studied as a function of holding time at 1873 K. From the plot in the probability graph, the log-normal distribution was found to be a good approximation for the spatial particle size. The contents of insoluble Ce obtained from chemical analysis were compared with those estimated from the data for particle size distribution by using various methods.