Interfacial Fluctuation Behavior of Steel/Slag in Medium-Thin Slab Continuous Casting Mold With Argon Gas Injection

The flow field of molten steel and the interfacial behaviour between molten steel and liquid slag layer in medium-thin slab continuous casting mold with argon gas injection was studied by numerical simulation, in which the effects of nozzle submergence depth and port angle, casting speed, and argon gas flow rate on the flow and the level fluctuation of molten steel were considered. The results show that the molten steel jet from the submerged entry nozzle (SEN) with three ports into the mold and form three re-circulation zones including one upper re-circulation zone and two lower re-circulation zones. Argon gas injection results in a secondary vortex flow in the upper zone near the nozzle. For a given casting speed and argon gas flow rate, increasing the side port angle and submergence depth of nozzle can effectively restrain the steel/slag interfacial fluctuation. Increasing the casting speed would prick up the level fluctuation. For a fixed casting speed, argon gas flow rate has a critical value, the interfacial fluctuation with argon gas injection are stronger than the case without argon gas injection when the argon gas flow rate is less than the critical value, but when the argon gas flow rate exceeds the critical value, the level fluctuation is calmer than that without argon gas injection.