Registration of Filtration Efficiency of Active or Reactive Filters in Contact with Steel Melt in a Steel Casting Simulator

Abstract

AbstractAspecial metal-casting simulator allowed to investigate the behavior of nozzles and filters in contact with a steel melt under controlled atmosphere. First, the clogging of carbon-bonded alumina nozzles with different active or reactive coatings was evaluated by introducing exogenous inclusions while monitoring the changes in melt flow with time. In addition, the microstructure of the nozzles was investigated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy to assess the coating decomposition and phase transformations. In further approaches, endogenous inclusions were generated in situ by pre-oxidizing and deoxidizing the steel melt. Filters with different active and reactive coatings were immersed for different times in order to investigate the evolution of newly formed phases on the filter surface as well as characterize their cleaning performance based on the analysis of the solidified steel. The inclusions in the frozen steel melt were characterized with the aid of an automatic SEM – ASPEX-system, which identified the chemistry as well as the size and population of the inclusions. In the last approach, investigations of a new combined refining process based on the immersion of reactive filters and a subsequent filtration via carbon-free active filters was investigated, in order to remove the remaining clusters of inclusions.