The wetting of refractories of the MgO-Al₂O₃-ZrO₂ system with metal melts

Conclusions

In the conditions of the experiments reported here, the materials are wetted by iron as soon as it melts. The wetting angle on corundum refractories is approximately half of that on spinel-based refractories.

Monoclinic zirconia added to the corundum or spinel reduces the wettability of the refractories by an iron melt at 1550°C. The wettability at 1550°C was lowest for a composition of 85% MgAl₂O₄+15% ZrO₂ (θ=85°).

The wetting of the refractories concerned here by an aluminum melt begins at a temperature above 1100°C. The wettability by aluminum is lowest for corundum refractories containing added ZrO₂. The degree of wetting by an aluminum melt of corundum containing up to 10 wt.% zirconia is lower than that of corundum alone.

The results of this investigation suggest that a refractory based on MgAl₂O₄ with 10 wt.% added ZrO₂ can be recommended for the production of the proportioner inserts used in the continuous casting of steel of various grades. In casting killed steels, i. e., steels which are deoxidized with a larger amount of aluminum, proportioner inserts produced from corundum with 2–5 wt.% added ZrO₂ can be expected to be sufficiently durable.