Interaction between microporous magnesia castable and 38CrMoAl steel

The microporous magnesia refractory shows a promising application prospect as tundish lining due to excellent thermal insulation and slag resistance. The effect of interaction between microporous magnesia castable and 38CrMoAl steel containing 0.876 wt.% Al on the cleanliness of 38CrMoAl steel was studied and compared with that of fused magnesia castable. The results show that the micropores in the microporous magnesia castable can promote the formation of dense and continuous MgO·Al₂O₃ layer, which can inhibit the further pollution of molten steel by refractories, whereas the MgO·Al₂O₃ layer formed in test of fused magnesia castable is not continuous. After 30 min holding, the total oxygen content in the steel samples for the test of microporous magnesia castable is only 42.2% of that for the test of fused magnesia castable. The inclusions in the steel samples for the test of microporous magnesia castable are also less than those for the test of fused magnesia castable. It shows that microporous magnesia castable is a promising tundish refractory for the preparation of clean high-Al steel.