Influence of Ce on Characteristics of Inclusions and Microstructure of Pure Iron

The experiments on adding Ce, Mn and S to molten iron have been carried out by means of the electric furnace, and the concentration of oxygen, the evolution of inclusions and microstructures of samples are analyzed, indicating that the concentration of dissolved oxygen decreases greatly after adding Ce. The calculated thermodynamics results at 1273 K performed on Factsage show that Ce2O2S and CeAlO2 are formed with the increase of Ce content for w(Ce) > 0.0002 and w(S) < 0.0001, while three cerium sulphides (CeS, Ce3S4 and Ce2S3, in sequence), MnS and Ce2O2S are formed with the increase of S content and the decrease of Ce content for w(Ce) > 0. 0002 and w(S) > 0.0001. These results are consistent with the SEM observations. Finally, some possible reasons are given to explain the formation of intragranular ferrite in the pure iron.