Nozzle Brick
What is nozzle brick
Nozzle brick refers to the refractory steel water outlet inlaid in the base brick at the bottom of the ladle. When not pouring, the nozzle brick and the plug brick are in line contact to ensure that there is no leakage of steel. The upper mouth of the nozzle brick is arc-shaped, so that it can open and close the nozzle and reduce the resistance to the flow of molten steel. The lower section is a straight section to stabilize the flow. When the capacity of the steel drum is constant, the inner diameter of the nozzle brick directly affects the pouring speed.
Depending on the volume of the ladle, the pouring method and the steel type, the nozzle diameter can be in the range of 20 to 120 mm. The nozzle bricks can be installed from the inside or outside of the ladle. Nozzle bricks can be made of clay, high alumina, magnesia, magnesia chromium and zirconium. When pouring boiling steel and high manganese steel, the clay nozzle is easy to be corroded, so magnesia or high aluminum nozzle bricks are used. The magnesia nozzle has strong corrosion resistance but also strong thermal conductivity, and it is easy to produce nodules during casting.
Chemical and physical properties of nozzle brick
| Item | Corundum Type | MgO-C Type |
|---|---|---|
| MgO (≥) | - | 76 |
| AL2O3% (≥) | 90 | - |
| C% (≥) | - | 14 |
| Apparent porosity (%)(≤) | 15 | 3 |
| Bulk density (g/cm3) | 2.95 | 2.98 |
| Cold crushing strength ,MPa (≥) | 50 | 40 |