Effect of interactions between Fe-Al alloy and MgO-based refractory on the generation of MgO center dot Al2O3 spinel

摘要

In the present study, interactions between Fe-2.1 wt-%Al and Fe-5.1 wt-%Al alloys and different tundish refractories, and a spinel generation in the Fe-Al alloys were investigated in laboratory experiments at 1550 degrees C in an alumina crucible using a high-frequency induction furnace. The results indicated that the formation of a spinel layer at the interface was owing to both the oxidation-reduction reactions and the phase transformation at the interface according to initial phases in refractories. The thickness of the interface layer increased with increasing the content of the [Al] in Fe-Al alloys, the SiO2 content in the refractory and the immersion time, however, the [Al] content was a dominant factor. Both experimental results and thermodynamic calculations concluded that MgO center dot Al2O3 spinel inclusions along with a small amount of CaO-MgO-Al2O3 were the main inclusions in Fe-Al alloys. MgO center dot Al2O3 inclusions were mainly formed at the interface by alloy/refractory interactions and then mechanically transferred into molten alloys.