The Role of Slag Carryover on the Non-metallic Inclusion Evolution and Magnetic Behavior in Electrical Steel

Abstract

In the present investigation, a set of high-temperature experimentations were carried out to improve the understanding of the influence of slag carryover (SCO) on non-metallic inclusion evolution during the production of high silicon electrical steels for functional applications. It was observed that the liquid steel treated with synthetic slag and lime resulted in the formation of CaO-based complex oxide, sulfide, and nitride inclusions in the matrix. Whereas the top slag (synthetic slag and lime) contaminated with carryover slag transforms the complex oxide inclusions to Mn free oxy-sulfide inclusions in the high Si steel. Further, the high-silicon steel evaluated for magnetic property confirms the detrimental magnetic behavior of the steel treated using the top slag with the excess amount of SCO (10 kg/t). The increase in coercivity is due to a higher fraction of sub-micron inclusions in the steel matrix. The industry implications of the present findings are highlighted in the light of the evolution of Goss texture in high silicon steel during downstream processing. The evolution of detrimental inclusions in functional grade (electrical) steels due to the presence of SCO call for stringent process control during the upstream processing of liquid steel to maintain the desired magnetic properties.