As the tundish nozzle is the key channel for molten steel from the ladle to the tundish, its degree of compatibility with the continuous casting process directly affects production stability, the quality of the cast product and cost control.
The following are systematic matching principles and technical solutions:
I. Matching Core Element Matrix
Process parameters Nozzle selection requirements Risk of mismatch
Steel type characteristics - High-oxygen steel: ZrO₂-C material + gas curtain protection Al₂O₃ blockage, nozzle erosion and perforation
- High-alumina steel: CaO coating to prevent blockage
Section type - Slab: wide-gap submerged nozzle (optimized flow field) slag entrapment, cracking
- Billet: straight-through nozzle (simplified flow)
Drawing speed range - High drawing speed (>1.8m/min): large-aperture nozzle liquid surface fluctuations, entrainment of protective slag
- Low drawing speed: small aperture + heating to prevent solidification
Continuous casting furnace number - Multi-furnace continuous casting: quick-change nozzle system
Slag type - High-alkali slag: MgO-C material is erosion-resistant
2. Matching Solutions For Typical Process Scenarios
Scenario 1: Continuous casting of stainless steel slabs
Challenge: The high Cr and Ni content of molten steel causes strong erosion
Nozzle solution:
Material: ZrO₂-C (ZrO₂≥85% at the slag line)
Structure: porous submerged nozzle (side holes inclined at 15°)
Support: argon gas annular gap protection (flow rate 6-8L/min)
Results: service life increased to 12 heats, 60% reduction in subcutaneous bubbles in the cast slab
Scene 2: continuous casting of high-alumina steel billets
Challenge: severe Al₂O₃ blockage
Nozzle solution:
Material: Al₂O₃-C+CaZrO₃ lining
Structure: slit-type anti-blocking design (slit width 0.3mm)
Process: calcium treatment ([Ca]/[Al]=0.10-0.15)
Effect: continuous pouring time extended from 40min to 120min
3. Key Matching Technologies
Flow field simulation optimization
Simulation of steel flow patterns using ANSYS Fluent for different nozzle structures
Optimization parameters: outlet angle (recommended 25-35°), insertion depth (80-120mm below the tundish liquid surface)
Thermodynamic matching design
Nozzle preheating system:
Al-C: baking curve 800°C → 1100°C (heating rate 10°C/min)
Zirconia carbon: baking curve 900°C → 1200°C (heating rate 8°C/min)
Temperature monitoring: infrared thermal imager ensures temperature difference <50°C
Dynamic adjustment system
Intelligent sliding mechanism:
hydraulic servo control (response time <0.5s)
Automatically adjusts the opening according to the drawing speed (control accuracy ±0.05mm)
