Sintered tabular corundum has good thermal shock resistance, high strength, and good wear resistance.
The upper and lower sliding plates and 4 refractory bricks for the upper and lower nozzles compose the ladle sliding nozzle. Each ladle of molten steel must pass through the upper and lower slides and the upper and lower nozzles. Firstly, they must have sufficient strength at high temperatures to withstand the static pressure of molten steel. Secondly, the upper and lower slides surface have to flat and smooth. The flat ladle sliding nozzle ensures no molten steel leaks during the pouring process. In the meantime, the sliding nozzle has to be resistant to erosion, corrosion and has good thermal stability to withstand sudden temperature changes. It needs a high performance of resistance to erosion of molten steel and erosion of molten slag.
The sliding nozzle plate is a key part that determines the function of the sliding nozzle. Due to the repeated contact of the sliding nozzle plate with high-temperature molten steel (especially the casting hole), it has high anti-corrosion ability. The sliding plate must have high strength, corrosion resistance, peeling resistance, etc., to gain good performance. During the pouring process, ensure that no molten steel leaks between the skateboards.
The sliding nozzle must have the following properties:
(1) The sliding surface should be smooth and flatness ≤0.05mm;
(2) High mechanical strength;
(3) Strong corrosion resistance to molten steel and molten slag;
(4) Not stick on molten steel.
The sintered tabular corundum can precisely meet those requirements.
Sintered tabular corundum has become a common raw material for sliding nozzle plates. Under normal circumstances, corundum-mullite-based raw materials are used to improve the performance of the sliding nozzle. Adding an appropriate amount of graphite (or carbon black) and antioxidants to the sintered tabular corundum can be developed to get an aluminum-carbon sliding nozzle. Or by mixing tabular corundum with zirconia, graphite (or carbon black), antioxidants can get the aluminum-zirconium-carbon sliding nozzle. Those types of the sliding nozzle above are mostly used in the steelmaking industry nowadays.