Influence of CaF2 and Li2O on the viscous behavior of calcium silicate melts containing 12 wt pct Na2O

Hyun Shik Park, Hyuk Kim, Il Sohn

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92 Citations (Scopus)


Understanding the viscous behavior of silica-based molten fluxes is essential in maintaining the reliability of steel casting operations and in preventing breakouts. In particular, high concentrations of aluminum in recently developed transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) steels tend to promote reduction of silica in the mold fluxes that result in the formation of alumina, which in turn increases the viscosity. To counteract this effect, significant amounts of fluidizers such as CaF 2 and Li2O are required to ensure that mold fluxes have acceptable lubrication and heat transfer characteristics. The viscous behavior of the slag system based on CaO-SiO2-12 wt pct Na2O with various concentrations of CaF2 and Li2O has been studied using the rotating spindle method to understand the effects on the viscosity with these additives. CaF2 additions up to 8 wt pct were effective in decreasing the viscosity by breaking the network structure of molten fluxes, but CaF2 concentrations above this level had a negligible effect on viscosity. Li2O additions up to 2 wt pct were also effective in decreasing the viscosity, but the effect was comparatively negligible above 2 wt pct. Using Fourier transform infrared (FTIR) analysis of as-quenched slag samples, it was concluded that the viscosity was controlled more effectively by changing the larger complex silicate structures of rings and chains than by changing the amounts of simpler dimers and monomers.

Original languageEnglish
Pages (from-to)324-330
Number of pages7
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Issue number2
Publication statusPublished - 2011 Apr

Bibliographical note

Funding Information:
This study was supported partially by the Brain Korea 21 (BK21) Project at the Division of the Humantronics Information Materials and the Yonsei University Research Fund of 2009.

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry


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