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A mathematical model has been developed to analyze molten metal flow, considering the effects of argon gas injection and static magnetic-field application in the continuous casting process. The kturbulence model is used to calculate the turbulent variables. A homogeneous fluid model with variable density is employed to tackle the molten metal-argon gas flow. The electromagnetic force is incorporated into the Navier-Stokes equation, and the effects of boundary conditions of the magnetic field on the velocity distribution near the mold wall are included. A good agreement between the numerically obtained flow-field results and measurements is obtained. The argon gas injection changes the molten metal flow pattern, mainly in the upper portion of the mold. By applying the magnetic field, values of the averaged velocity field in the bulk decrease significantly, and, especially at the top free surface, they become very small, which can cause meniscus freezing. When magnetic-field application and argon gas injection are used together, the external flow field out of the gas plume is significantly suppressed; nevertheless, flotation of gas bubbles is still active and is not affected directly by the magnetic field. Although the penetrating length of the gas plume is shortened, the argon gas bubbles in molten steel still cause fluctuation at the top free surface, which prevents the occurrence of freezing.

Biased flow occurs frequently in the slab continuous casting process and leads to downgraded steel quality. A mathematical model has been developed to analyze the three-dimensional biased flow phenomena associated with the effects of static magnetic-field application and argon gas injection in the slab continuous casting process. By moving the submerged entry nozzle (SEN) from center to off-center, the biased flow and vortexing flow in the mold can be reproduced in the numerical simulation. The existence of a vortexing flow is shown to result from three-dimensional biased flow in the mold. A vortex is located at the low-velocity side adjacent to the SEN. The vortex strength depends on the local horizontal velocity of molten steel and decreases gradually with distance from the free surface. The vortexing-zone size depends on the biased distance of the SEN, and the intensity of the vortexing flow depends on the casting speed of the continuous caster. Only when the location and strength of the magnetic field are properly chosen, can the vortexing flow be suppressed by a static magnetic-field application. The effect of argon gas injection on the vortexing flow is not remarkable. The combination of magnetic-field application and argon gas injection can correct the biased flow and suppress the vortexing flow by suppressing the surface velocity and removing the downward velocity near the SEN in the mold.

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〈111〉-oriented twin free Tb–Dy–Fe single crystals, 〈112〉- and 〈110〉-oriented twinned “single” Tb–Dy–Fe crystals were prepared using floating zone melting technique. Magnetostrictive performances of the crystals were investigated. Better low-field properties were observed in the 〈110〉 twinned crystals than in the 〈112〉 crystals. The highest properties were achieved in the 〈111〉 twin free single crystals. Even though there are still oxidized particles in the present 〈111〉 single crystals, a large magnetostrictive jump of 1700 ppm and a very low saturation magnetic field of 500 Oe were obtained. To understand magnetization and magnetostriction of different Tb–Dy–Fe crystals, theoretical modeling was carried out based on a simplified domain rotation model. Magnetization moment rotation paths of different domains were simulated and hence the resultant magnetostriction was obtained, which can well account for the experimental results of different crystals. The limitation of the domain rotation model was also discussed.