Estimation of liquidus temperature for B2O3- and TiO2- containing fluoride free mould fluxes from activation energy for viscous flow and DTA measurements

Liquidus temperatures of fluoride free mould fluxes simultaneously containing B2O3 and TiO2 have been estimated from two methods, the activation energy for viscous flow and the DTA technique. Generally, the liquidus temperatures determined from the two methods are in good agreement. With the increase in B2O3 and TiO2 content, the variation of liquidus temperatures for fluoride free mould fluxes estimated from the two methods is consistent. As the TiO2 content increases, liquidus temperatures of the slags initially decrease and then increase. With the increase in B2O3 content, the liquidus temperatures of the slags decrease. Further quenching experiments reveal that there is no crystal precipitation in the slag at the liquidus temperature determined from DTA, while some crystal can be observed in the slag at the liquidus temperature determined from the activation energy for viscous flow. Superheating and supercooling effects which could bring errors in determining liquidus temperature by using the two methods are discussed.