Research and Application of Low Total Iron Control in Converter Final Slag
Based on the research of domestic and foreign scholars on total iron in converter final slag and slag dephosphorization,combined with the actual production of a 120 t converter,an experiment on controlling low total iron in final slag was carried out on 40Cr steel.The experiment followed the principle of"earlier formation of early-stage slag,improving the dephosphorization rate of early-stage slag in smelting,and thorough slag melting without re-drying during the process".The lance position was optimized from a three-stage to a five-stage.By stirring at a low lance position at the end,the reaction at the metal-slag interface was promoted,dephosphorization reaction was accelerated,and the FeO in the slag was reduced simultaneously,achieving the purpose of meeting the requirements of the steel grade for phosphorus at the end while reducing the total iron in the slag.Good experimental results were achieved:the average w(TFe)in the slag was 13.59％,which was 2.50％lower than the actual production;the average dephosphorization rate was 92.40％,which was 2.80％higher than the actual production.Through the analysis of slag mineral phases,it was verified that reducing the final FeO in the slag promoted the enrichment of phosphorus in the slag,the generation,growth of solid phosphorus phase C2S,and the precipitation of high melting point phase MgO,and reducing the phase of MgO+CaO+FeO in the slag could reduce the total iron content.After the industrial promotion and application,the total iron in the final slag of the converter was controlled at 14.60％,realizing the control of low total iron in the final slag of the medium and high carbon steel converter.
medium to high carbon steelhigh tensile carbondephosphorizationfinal slag TFesolid phosphorusphase C2S
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