Austenite grain size distribution and topological properties in Fe-0.09 to 0.53 mass%C-0.02 mass%P alloys containing primary inclusions of Ce2O3 and CeS

The effects of the primary inclusion of Ce2O3 (the mean planar diameter, (d) over bar(A)=1.6 to 2.1 mu m) or CeS ((d) over bar(A)=2.2 to 2.8 mu m) particles on austenite grain size and grain shape distributions were studied in Fe-0.09 to 0.53 mass%C-0.02 mass%P alloys, which were continuously cooled from 1 873 to 1 673 K, followed by holding for 0 to 180 min. It was found that the shape of the relative spatial grain size distribution, D-V/D-V,D-mean (the mean grain diameter), was invariant with respect to the content of carbon, the number of Ce2O3 or CeS particles (the volume fraction of particle, f(V)=0.02 to 0.19%) and holding time. The spatial grain size distribution could be best described by the log-normal distribution function. The heterogeneity parameter, D-max (the maximum grain diameter)/D-V,D-mean mean ratio in three dimensions, increased with an increase in the f(V) value. The distribution of the number of grain sides and the grain size distribution for each grain side follow approximately the log-normal distribution function, and these results were consistent with those observed in previous experimental results for normal grain growth, in which a second-phase particle was not present.