Submerged Entry Nozzle: 5 Methods to Prevent SEN Clogging

The submerged entry nozzle (SEN) is a critical component in the continuous casting process of steel production. Its primary function is to deliver molten steel from the tundish to the mold while minimizing oxidation and turbulence. However, SEN clogging is a common issue that can disrupt operations and reduce product quality. Here are five proven methods to prevent SEN clogging:

1. Argon Shrouding (10-15L/min)

Argon shrouding is a widely used technique to prevent clogging in submerged entry nozzles. By injecting argon gas at a rate of 10-15 liters per minute, you can create a protective atmosphere that reduces the formation of alumina (Al2O3) deposits. This method helps maintain a smooth flow of molten steel and minimizes the risk of clogging.

2. Calcium-Treated Steel to Reduce Al2O3

Using calcium-treated steel is another effective way to prevent SEN clogging. Calcium reacts with alumina to form calcium aluminate, which is less likely to adhere to the nozzle walls. This treatment significantly reduces the accumulation of deposits and ensures a consistent flow of molten steel.

3. Preheat at 300°C/h

Preheating the submerged entry nozzle at a rate of 300°C per hour is crucial to prevent thermal shock and clogging. Proper preheating ensures that the nozzle reaches the optimal temperature before coming into contact with molten steel, reducing the risk of crack formation and deposit buildup.

4. Coat Inner Walls with BN/MgO

Coating the inner walls of the submerged entry nozzle with boron nitride (BN) or magnesium oxide (MgO) can significantly reduce clogging. These coatings provide a smooth surface that minimizes the adhesion of alumina and other deposits, ensuring a consistent flow of molten steel.

5. Regular Ultrasonic Thickness Checks

Regular ultrasonic thickness checks are essential to monitor the condition of the submerged entry nozzle. These checks help detect any thinning or wear in the nozzle walls, allowing for timely maintenance or replacement. By keeping the nozzle in optimal condition, you can prevent clogging and ensure efficient steel casting operations.

In conclusion, preventing submerged entry nozzle clogging is essential for maintaining the efficiency and quality of the continuous casting process. By implementing these five methods—argon shrouding, calcium-treated steel, preheating, coating inner walls, and regular ultrasonic checks—you can significantly reduce the risk of clogging and enhance your steel production performance.