Physical Modeling of Asymmetrical Flow in Slab Continuous Casting Mold due to Submerged Entry Nozzle Clogging with the Effect of Electromagnetic Stirring

Abstract

Submerged Entry Nozzle (SEN) clogging is a serious problem for continuous casting process and slab quality. In order to investigate the impact of the SEN clogging rate on the flow field and the optimization effect of electromagnetic stirring (EMS) on the asymmetrical flow due to the SEN clogging, a 1:5 scaled mercury model, with various SEN clogging rates and different electromagnetic stirring currents was established and the flow velocity was measured by means of Ultrasonic Doppler Velocimetry (UDV). S index is introduced to judge quantitatively whether the horizontal flow pattern is symmetrical or not. The results show that the symmetry of the flow pattern in the mold becomes broken with the increase of the SEN clogging rate. In this study, EMS is an effective method to increase S index and active the free surface flow when the SEN clogging rate is under 50%. However, the stirring current of EMS should be controlled to avoid the adverse surface flow which may induce slag entrapment.

Influence of M-EMS on Fluid Flow and Initial Solidification in Slab Continuous Casting

“…It can be seen that electromagnetic force increases with the EMS current, as the EMS current increases from 400 to 800 A, the maximum electromagnetic force is 2133 N/m 3 and 7950 N/m 3 . In order to validate the mathematical model, a 1/5th scaled physical model using mercury when EMS is not applied was established; the fluid velocity in the mold was measured by means of ultrasound Doppler velocimetry (UDV), and Li et al [30] as the authors published this apparatus' description in ISIJ International. Meanwhile, a mathematical model was set corresponding to the physical model both on the geometry and material properties, etc.…”

Influence of EMS on Asymmetric Flow with Different SEN Clogging Rates in a Slab Continuous Casting Mold

“…This means that the distribution of the temperature field with SEN clogging is not uniform, inducing the non-uniform development of the solidified shell. In our previous paper, we introduced the symmetric index S to quantitatively judge whether the horizontal flow pattern is symmetric or not [31]. In this study, we chose the symmetry of the horizontal plane where the electromagnetic force reached its maximum to characterize the symmetry of flow field with SEN clogging.…”

Steel/Slag Interface Behavior under Multifunction Electromagnetic Driving in a Continuous Casting Slab Mold

“…They show good agreement between the predictions and UDV measurements. More experimental details are given in previous research [29]. The physical experiment system is shown in Figure 2c.…”

“…In fact, recent studies have shown that the appropriate use of combined stirring and braking has the potential to optimize the flow of molten steel and to compensate for the limitations of a single electromagnetic field [24,25]. Multifunction electromagnetic driving which combines EMS and EMBr is the development trend of the current control technology of steel flow in a continuous casting mold [26][27][28][29]. However, there are few studies on the steel/slag interface behavior under multifunction electromagnetic driving.…”