Ferroalloy quality and steel cleanliness

Abstract

Ferroalloys are added during secondary steelmaking to impart special properties to the steel. Depending upon the ferroalloy quality this may lead to the formation of inclusions. The present knowledge lacks in the exact content of the individual elements and the nature of inclusions dispersed in the ferroalloys. In order to broaden the knowledge concerning ferroalloy quality, eight different ferroalloys (i.e. FeMo, FeNb, HCFeMn, LCFeMn, FeTi70, FeTi35, FeSi75 and FeP) were characterised for their impurity content. The samples were investigated for chemical analysis (inductively coupled plasma atomic emission spectroscopy and Leco combustion technique) and microstructural analysis (SEM energy dispersive spectroscopy). These impurities are linked to the ferroalloy manufacturing route. The inclusions observed in the microstructure are in good agreement with the inclusions extracted by the dissolution technique. In the present manuscript, the possible influence of ferroalloy quality over steel cleanliness is evaluated in the context of the impurities extracted and observed in the ferroalloys.