What precautions should I take when replacing a zirconia tundish nozzle?

 

Principles for Replacing Zirconia Tundish Nozzles: Cooling - Cleaning - Installation - Inspection.

 

 

Replacement under high-temperature conditions directly leads to safety incidents; cooling is the primary prerequisite.

 Required cooling temperature: The ladle must cool from post-pouring high temperatures to ambient temperature (≤50°C). Use an infrared thermometer to check temperatures on the ladle body and nozzle mounting hole area. Under no circumstances should the old nozzle be dismantled while the ladle is hot or retaining residual heat.

 Cooling method: Use natural cooling. Avoid direct water spraying on the ladle nozzle to prevent refractory materials from cracking due to rapid cooling, which could affect future use.

 

 

 

When dismantling the old nozzle, avoid mechanical damage while removing residual impurities to clear obstacles for installing the new nozzle.

 Safety precautions: Operators must wear heat-resistant gloves, safety goggles, and dust masks. When using tools, avoid excessive force that could cause the old nozzle to shatter and scatter fragments.

 Old Nozzle Removal: First remove securing clamps, bolts, or clips. Then slowly extract the old nozzle from the mounting hole using specialized tools. If the nozzle is tightly bonded to refractory mortar, gently pry the gap with tools-never strike the ladle body directly.

 Installation Hole Cleaning: Thoroughly remove residual refractory mortar, steel slag, and zirconia debris from the installation hole using a wire brush or specialized scraper. Ensure the hole walls are smooth with no protrusions or depressions.

 

 

The quality of the new nozzle installation directly determines its subsequent performance.

 New Nozzle Inspection: Before installation, inspect the new nozzle's appearance to confirm no cracks, chipped corners, or other defects. Measure dimensions such as inner diameter and length to verify compliance with design requirements.

 Positioning and Calibration: Align the new nozzle with the installation hole and insert it slowly. Use a level or laser alignment tool to calibrate the nozzle's verticality, ensuring the nozzle center is perfectly aligned with the ladle tapping channel and the mold center. Deviation must not exceed 2mm to prevent molten steel flow deviation and subsequent mold liquid level fluctuations.

 Sealing Treatment: Uniformly fill the gap between the new nozzle and the mounting hole with specialized refractory sealing clay, or install a refractory fiber sealing ring. Ensure the filling material is compacted without voids.

 

 

After replacement, conduct thorough checks to eliminate potential hazards and document findings for future traceability.

 Visual Inspection: Verify accurate nozzle installation, ensure sealant is fully compacted, and check for gaps or loosening.

 Dimensional Verification: Re-measure critical dimensions-including height from nozzle tip to ladle bottom and inner diameter-to confirm compliance with continuous casting requirements. This prevents flow control issues caused by installation deviations.

 Recording and Archiving: Document the replacement date, operator, new nozzle specifications, and reason for scrapping the old nozzle. This facilitates tracking nozzle lifespan and optimizing replacement cycles.

 

 

1. Mixing nozzles of different materials or specifications is strictly prohibited to prevent operational failures due to performance mismatches.
2. If immediate use is required after replacement, thoroughly preheat both the ladle and nozzle according to preheating requirements. Skipping the preheating step before pouring is strictly forbidden.
3. Disassembled old nozzles must be disposed of according to relevant standards and specifications. Do not discard them arbitrarily to prevent environmental impact from zirconia materials.

 

Anyang Changtai Silicon Industry Co., Ltd. is a comprehensive manufacturer specializing in the design, processing, and sales of zirconia high-temperature products. If you require zirconia high-temperature products, please email us at: zhang@ayctgy.com. We will respond to your inquiry promptly upon receipt.