Continuous casting process-10. Immersion nozzle & function

10. What is the immersion nozzle? What is its function?

The immersion nozzle is to lengthen the tundish nozzle and insert it to a certain depth below the copper surface of the mold, which seals the flow. The advantage of using the diffuser nozzle is: it isolates the contact between the injection stream and the air, prevents the injection stream from impacting the molten steel surface, and the flying storage on the surface prevents secondary oxidation. Through the choice of nozzle shape, the flow state of molten steel in the mold can be adjusted. To promote the separation of inclusions. Improve the quality of copper. It can be said that the mold uses the immersion nozzle to protect the flow injection, which has brought epoch-making progress to the development of continuous casting technology. The shape of the immersion nozzle mainly refers to the angle of the outlet of the steel. There are generally four types: straight hole type, side hole up, side hole down, and box type. Which one to choose depends on the pouring speed and the cross-sectional size of the mold.

Its generally believed that the immersion nozzle protection technology is only suitable for bloom and slab continuous casting, and the small square field less than 150*150 mm, due to the small cross-section, the size of the flooding nozzle is limited, and the drawing speed is fast, and the liquid level fluctuates. Large, easy to cause slag, so it is difficult to use this method.

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Daisy Zhai