Numeric Simulation of the Steel Flow in a Slab Caster with a Box‐Type Electromagnetic Stirrer

Abstract

The usage of electromagnetic actuators in the continuous steel‐casting process is on a steady rise, due to its possibilities for a sophisticated, contactless flow control. The complexity of the casting process and the ever‐increasing quality demands require a well‐founded knowledge of the interaction between the electromagnetic actuators and the liquid steel flow. Numeric modeling provides a detailed view and is therefore crucial for understanding the interaction between the electromagnetic fields and the liquid steel flow. Only a deep insight into the coupling between the liquid steel flow and the electromagnetic forces makes it possible to improve/optimize the continuous casting process. The work presented here is part of an ongoing research to bridge the gap between the liquid steel flow and the grain structure of the end product. The article's focus lies on the liquid steel flow modified by a traveling magnetic field—relying mainly on numerical simulations. Different modeling approaches are used to simulate linear electromagnetic stirring in the secondary cooling zone of a slab caster. An appropriate model is chosen to investigate the influence of various stirring parameters, stirring modes, and stirring positions. From the results, conclusions for the real casting process can be drawn.

Impact of Electromagnetic Stirring Roller Arrangement Pattern on Magnetic Field Simulation and Solidification Structure of PW800 Steel in the Second Cooling Zone

“…Typically, while performing numerical calculations for electromagnetic fields, certain assumptions are made to simplify the calculations while still guaranteeing that the desired results match the necessary criteria as follows [ 13 , 15 ]: Given the ample space surrounding the electromagnetic stirring device, there is assurance that the magnetic field lines can form a closed loop and are not significantly affected by the external magnetic field. Therefore, it is assumed that the magnetic field in the proximity of the magnetic pole is uniformly distributed, with the magnetic field lines passing through the pole oriented at a right angle to the surface of the pole; The physical parameters are time-invariant constants due to the small variation in the physical parameters of the molten steel during the continuous casting process; Considering the magnetic Reynolds number being less than 1 during electromagnetic stirring in the continuous casting process, it is assumed that the electromagnetic field is barely affected by the slow flow of molten steel (0.9 m/min) [ 16 ]; The electromagnetic field generated by electromagnetic stirring can be considered a quasistatic field due to the low frequency of the alternating current (5–9 Hz). …”

“…Considering the magnetic Reynolds number being less than 1 during electromagnetic stirring in the continuous casting process, it is assumed that the electromagnetic field is barely affected by the slow flow of molten steel (0.9 m/min) [ 16 ];…”

Numerical Simulation of Segregation in Slabs under Different Secondary Cooling Electromagnetic Stirring Modes

“…(6) Solutes transport equation [20]: (24) where Sc t represents the Schmidt number, which is set to 1.0 [21]; S d denotes the molecular diffusion source term; S c signifies the convective diffusion source term; D l,i stands for the diffusion coefficient of the solute element in the liquid phase; D s,i represents the diffusion coefficient of the solute element in the solid phase; c i denotes the concentration of the solute element; c l,i is the local average concentration of the solute element in the liquid phase; c s,i is the local average concentration of the solute element in the solid phase; and k i denotes the equilibrium distribution coefficient of element between solid and liquid phases.…”

The Angular Velocity as a Function of the Radius in Molten Ga75In25 Alloy Stirred Using a Rotation Magnetic Field

“…The magnetic induction causes a melt flow, and its simulation is complicated and needs correct data, like the ω(B, r) function. It is known that obtaining information about the melt flow from industrial casting is impossible, so we must conduct some cold experiments with well-monitored parameters (like Hg, Ga, GaIn, and GaInSn alloys) [19][20][21][22][23][24][25][26][27]. Because only very little correctly measured data for the ω(B, r) function can be found in the literature [21][22][23]25,[28][29][30][31][32][33][34][35], any previous simulations of the melt flow induced by an RMF ignored the function to solve the problem mentioned above [6][7][8][9][10][11].…”