Effect of TurboSwirl on Inclusions during Ingot Casting of Steels

Abstract EN

The use of TurboSwirl to obtain an improved steel cleanliness during filling of an ingot was numerically studied by VOF and DPM models.

It was found that a radius-reduced TurboSwirl or a proper tapered mold entrance nozzle with an adequate developed region for steel flow can reduce the risk of mold flux entrapment in a mold.

The ingot casting process can create highly turbulent conditions inside the mold during the initial stages of casting.

Since the TurboSwirl generates much calmer filling conditions it can promote separation of large nonmetallic inclusions.

The TurboSwirl also collects large inclusions (200 μm) towards the axis of rotation, which should promote agglomeration.

In addition, the residence time for inclusions of small sizes can be prolonged, increasing chance of agglomeration, which indirectly promotes their separation from steel.

Moreover, the average turbulent dissipation rate in an ingot casting swirl setup is about 40 % higher than that in a no swirl setup.

This further facilitates the agglomeration of inclusions before they enter the mold.

The removal of nonmetallic inclusions is thus enhanced because of an increasing inclusion collision rate due to both Stokes collisions and turbulent collisions, while maintaining a calm flow inside the mold.