Influence of La₂O₃ on Physical Properties of B₂O₃-containing Fluoride- free Casting Powder

In order to solve the problem that B₂O₃-containing fluoride-free casting powder tends to refrain the formation of crystals,crystallization properties of the fluoride-free mold casting powder and heat transfer of slag film were investigated with the basicity（CaO/SiO₂） of casting powder at 0.9,compositions of 27% ~36.47% w_CaO,30% ~40.5% w_SiO2,4% w_Al2O3,5% w_MgO,8% w_Na2O,2% w_Li2O and 4% w_B2O3 and the increase of w_La2O3 from 0 to 20%.The research shows that La₂O₃ can increase the thickness,crystallization ratio and crystallization temperature of slag film and reduce the melting temperature of the molten slag,thus effectively improveing heat transfer performance of the mold.