The theoretical and numerical calculation and experimental study on soft contact electromagnetic casting forming
Based on classical electromagnetic theory, the electromagnetic pressure calculation model and the formula of electromagnetic casting forming have been established. Theoretical and numerical results indicated that the frequency, current density, relative permeability of alloy melt and resistivity can also influence the effect of electromagnetic pressure. Meanwhile, the effect of metal physics properties parameters on the value of electromagnetic pressure is more complicated. The needed magnetic field for casting Al-Si alloys liquid column with length of 0.05m in experiment was very close to the theoretical value. This result indicated that the formula of electromagnetic casting forming can be used to guide experiments and the actual industrial production.
Numerical Simulation of Heat Transfer and Deformation of Initial Shell in Soft Contact Continuous Casting Mold Under High Frequency Electromagnetic Field
Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromagnetic parameters were obtained from the previous studies. Owing to the induction heating of a high frequency electromagnetic field (20 kHz), the thickness of initial solidification shell decreases, and the temperature of strand surface and slit copper mold increases when compared with the case without the electromagnetic filed. The viscosity of flux decreases because of the induction heating of the high frequency electromagnetic field, and the dimension of the flux channel increases with electromagnetic pressure; thus, the deformation behavior of initial solidification shell was different before and after the action of high frequency electromagnetic field. Furthermore, the abatement mechanism of oscillation marks under high frequency electromagnetic field was explained.
Calculation of the free surface shape in the electromagnetic processing of liquid metals
Abstract An iterative numerical procedure has been developed to predict the free surface shape of the molten metal pool in electromagnetic processing techniques such as induction melting and semi-levitation melting. This required the calculation of the free surface shape to be coupled with the calculation of the e.m. field. The finite element method has been used to calculate the electromagnetic field and has included consideration of the skin effect in all conductors. Special care was taken in discretizing the billet in order to obtain a good representation of the change in the shape at the top. The pinch effect of the coil current on the free surface shape has been clearly shown. The software has been used to predict the shape of the melt in a conventional careless medium frequency induction melting furnace, and satisfactory agreement has been reached between the calculated and the experimentally measured shapes. The model has also been used to predict the meniscus shape in a semi-levitation melting furnace.