Reason analysis

1.1 The long nozzle is installed crookedly

One side of the molten steel is already on the edge of escaping, that is to say, the molten steel has had a large area of contact with the steel shell of the sprue and has been adhered. The torsion force is bound to bring about the rupture of the sewer. As shown in the figure, if the molten steel continues to leak, it will form a steel return phenomenon.

1.2 Long nozzle without asbestos gasket

If the asbestos gasket is not covered, it will inevitably cause a rigid fit between the long shroud and the sewer. In this way, it is difficult to achieve a close fit, and the molten steel will easily overflow and melt and damage the steel shell of the lower nozzle and cause the long nozzle to stick to the nozzle. When there is little contact between the molten steel and the steel shell of the sprue, the one-side steel shell of the sprue that has been used once is melted and damaged. When the molten steel is in contact with the steel shell of the ladle lower nozzle for a long time, the nozzle will be directly burned out.

1.3 The matching angle of the long nozzle, asbestos pad and the nozzle is different

After the previous investigation, we have found that there is a relatively large difference in the matching angle between the three, which makes the three parts that should be in contact with the cone surface become line contact. We all know that line contact cannot restrict the rotation of objects. This also brings hidden dangers to our cooperation. It is easy to form a gap when the three are matched together, which provides a possibility for molten steel to overflow.

1.4 The secondary diameter of the water outlet is reduced

The design of the tertiary continuous sliding nozzle is modeled on the secondary continuous sliding nozzle, and the diameter of the nozzle is reduced by 20mm down from the contact with the nozzle sleeve. During the use of the nozzle, stress concentration occurs, and the nozzle is broken due to the force.

1.5 The aperture of the long nozzle is small, resulting in secondary flow control

Through statistics on the fracture of the runner and the spitting of steel, it is found that the ladles with spitting from the runner all occur on the ladle with continuous slippage. Through on-site measurement, the diameter of the long nozzle protected by the continuous casting sleeve is only Φ65mm, while the runner of the continuous slippery ladle is only Φ65mm. The hole diameter has been expanded to Φ69mm. During the pouring process, the long shroud has had secondary flow control. At the same time, the inner wall of the long shroud has been stuck with cold steel. Oxygen burning of the residual steel can no longer restore the long nozzle hole diameter to its original size, resulting in continuous slippage. Steel spitting occurs after the ladle covers the long shroud.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality long nozzle are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

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