| Together with the deoxidation and desulphurizaton behaviors of RE (rare earth element) treated molten steel, the changes in shape, size, and constitution of the RE inclusions after RE treatment were studied in 0.3%C-1.3%Mn-0.02%S steel using high frequency induction furnace with magnesia crucible. It was found that little additional deoxidation occurred when RE addition was made to the molten steel pre-deoxidized with 0.05% Al, whilst considerable desulphurization was observed. The effectiveness of desulphurization increased with the amount of RE added. It is believed that the desulphurization occurred mainly by the formation of RE-sulphide rather than RE-oxysulphide and the growth of RE-sulphide was accelerated by the induction stirring. During holding after RE treatment, resulphurization and fading of globular RE-inclusions, accompanied by the formation of MnS, occurred possibly due to the reoxidation of the molten steel. |
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