Characteristics of Heat Flux Through Slag Film of Mold Slag Used for High Al-TRIP Steel Casting

Due to the high content of the Al-TRIP steel, Al reacts with SiO2 in the mold slag during the casting process, which results in the increase of wAl2O3/wSiO2 ratio and the Al2 O3 content, respectively; the characteristic of heat transfer through the slag film is then changed, which influences the smooth operation of the continuous casting process. The heat flux simulator of mold slag film was used to study the change tendency of the heat flux density through slag film and the results were discussed; at the same time, the characteristics of the crystals in the No. 15 mold slag were determined by BSE and XRD. The results obtained show that heat flux density decreases with the increase of wAl2O3/wSiO2 ratio. Heat flux density increases with the increase of Li2 O and/or B2 O3 content in the mold slag which contains 30% of Al2 O3. Compared with the heat flux density of common slag of peritectic steel, a suitable mold slag containing 4% of B2 O3 and 4% of Li2 O is designed. The heat flux density is 0. 645 MW/m2 when wAl2O3/wSiO2 = 1. 46. Under this experimental condition, the CaF2 crystals precipitate in the mold slag used for Al-TRIP steel.