In continuous casting steel equipments, the submerged nozzle is mounted on bottom of tundish and is inserted in the fireproofing casing tube used for casting steel below the level of molten steel of crystallizer. Its main function is to prevent the tundish beam from reoxidization and prevent the splash of molten steel in order to avoid the covering slag of the crystallizer to be involved in the molten steel, such to improve the fluid state of beam in the crystal and beam distribution. Al2O3-ZrO2-C submerged nozzle is mainly made of corundum and graphite in addition of metallic silicon and silicon carbide etc., molded in isostatic pressing machine and made by burning in reducing atmosphere. The part of slag line adopts the compound ZrO2-C material. The nozzle has even texture, abrasion and erosion resistance and good thermal shock stability, suitable for casting of various steel sorts.
Main chemical and physical index:
Item
Index
Main body
Slag line
Ventilation
Main body
Slag line
Al2O3 (%) no less than
35
35
45
F.C+SiC (%) no less than
20
15
15
20
15
ZrO2 (%) no less than
70
50
Apparent porosity (%) no more than
≤19
≤20
≥18
≤19
≤20
Normal temperature compressive strength (Mpa) no less than
17
15
16
15
Normal temperature bending strength (Mpa) no less than