Flow Behavior And Controlling Of Molten Steel In Continuous Casting Process

Tundish and mold are the important metallurgical vessels in continuous casting process. In this paper, the numerical simulation has been employed to investigate the flow behavior of molten steel in an asymmetric tundish and a round billet mold with electromagnetic stirring. The flow field and residence time distribution (RTD) curve in the tundish were studied by the standard k-s turbulence model, the RNG k-ε turbulence model and the k-co turbulence model respectively in CFX software. Then flow characteristics of molten steel in the tundish were analyzed by RTD.The back flow region in the tundish calculated by k-ω model is more obvious than that calculated by the two other models. The value of velocity at free surface is also biggest calculated by k-ω model, which is13.97%bigger than the standard k-s model, and is32.87%bigger than RNG k-s model. However, the average residence time calculated by standard k-s model is longest as well as the dead zone volume fraction is minimum. The average residence time calculated by standard k-ε model is452.841s, and the dead zone volume fraction is2.19%.The induced current field as well as the electromagnetic field in the round billet mold was solved by finite element method. Besides, the electromagnetic field with different current intensity and different current frequency was also calculated. Then, the electromagnetic force was added into the momentum equation as a source term in order to solve the flow field of molten steel in the round mold. Moreover, the effect of different electromagnetic stirrer position on the flow field was demonstrated.The magnetic field generated by electromagnetic stirring is a rotating magnetic field in the round billet mold. The magnetic induction increases with the increasing coil current intensity, and decreases with the increasing of coil current frequency. The flow field is most affected when the electromagnetic stirrer is installed at the mold. The affected region is mainly at the stirrer and a large region beneath the stirrer. The radial velocity of molten steel at the free surface with electromagnetic stirring increases by one order of magnitude than that without electromagnetic stirring as well as the tangential velocity increases by two orders of magnitude. The electromagnetic stirrer position directly affects the quality of casting billet quality. The flow field is determined mainly by the stirrer position. When the electromagnetic stirrer is installed below the free surface of mold as300mm,500mm and900mm, the tangential velocity of molten steel at the free surface is0.648m/s,0.608m/s and0.235m/s, respectively. The flow field at the free surface of the mold can be improved effectively by proper electromagnetic stirrer position.