Observations of Crystallization in Mold Slags with Varying Al_2O_3/SiO_2 Ratio

摘要

The present paper is an investigation into how the Al_2O_3/SiO_2ratio in the compositions of mold slags influences the crystallization behavior ofmolten slags. The experimental work is based upon observing the crystallization events through a Confocal Scanning Laser Microscopeequipped with a hot-stage. The study is motivated by the variation in crystallization that might occur in mold slags due to the pickup of aluminaduring continuous casting of high Al containing TRIP steels. The crystallization temperature was found to increase with increasing Al_2O_3/SiO_2ratio, and the crystal morphology was dependent upon the chemical composition and isothermal temperature. The crystallization path wascomplex, with CaF_2found to precipitate first, and followed by a second precipitation event. In this event, the precipitated phase dependedon the chemical composition of mold slag and changed from cuspidine to gehlenite as the mass ratio of Al_2O_3/SiO_2was increased beyond 0.65,and finally Al_2O_3was observed when the alumina content was 30wt.% (corresponding to a mass ratio of m_(Al2O_3_)/m_(SiO_2)=1.42).