Chemical characteristics of inclusions formed at various stages during the ladle treatment of steel

Abstract

AbstractAbstractIndustrial data were analysed to shed some light on the formation and growth of non-metallic inclusions during the ladle treatment of a particular grade of tool steel, Orvar Supreme (Fe-0·39C-1·0Si-0·4Mn- 5·2Cr-1·0Mo-0·9V). Seven types of inclusions were detected in samples taken along the processing evolution of the steel. The types of inclusions present were found to vary with the various stages of that evolution. While additions of aluminium to the steel bath were found to affect the composition of the inclusions, only a small number of pure alumina inclusions, agglomerated as clusters, were observed during the initial stages of deoxidation. Ladle glaze was found to be the major source of the inclusions. Most of those left in the steel before tapping were found to be of very small size and to contain high concentrations of Al2O3 and CaO and relatively minor ones of MgO and FeO.