A Study of the Heat Transfer Behavior of Mold Fluxes with Different Amounts of Al2O3

The element Al in molten aluminum containing steel reacts with the liquid mold flux and thus be transferred into the mold flux during the continuous casting process. Additionally, the increase in alumina in a mold flux changes its performance significantly. Thus, in this paper, the heat transfer properties of mold fluxes with the Al2O3 content ranging from 7 to 40 wt. % were studied with the Infrared Emitter Technique (IET). Results found that heat flux at the final steady state decreased from 423 kW·m−2 to 372 kW·m−2 with the increase in Al2O3 content from 7% to 30%, but it increased to 383 kW·m−2 when the Al2O3 content was further increased to 40%. Both crystalline layer thickness and crystalline fraction first increased, then decreased with the further addition of A2O3 content. Moreover, it indicated that the heat transfer process inside the mold was dominated by both a crystallization of mold flux and the resulting interfacial thermal resistance. Further, the Rint increased from 9.2 × 10−4 m2·kW−1 to 11.0 × 10−4 m2·kW−1 and then to 16.0 × 10−4 m2·kW−1 when the addition of Al2O3 content increased from 7% to 20% and then to 30%, respectively; however, it decreased to 13.6 × 10−4 m2·kW−1 when the Al2O3 content reached 40%