Numerical Simulation Of High Pure Aluminum During Low Frequency Electromagnetic Casting

In recent years, the high pure aluminum is used more and more widely, such as electronic industry, aerospace and other fields, especially as the high pure aluminum target. The purity and the grains size are the main qualification of the high pure aluminum target. This paper aims to apply electromagnetic field of double coils and change the casting parameters, the high pure aluminum grains are uniform in the process of semi continuous casting, which will provide a technical support for the high purity aluminum target production.In this paper, a coupled mathematic model of the interaction of multi-physical fields, which applies to both the conventional DC casting and low frequency electromagnetic casting processes, has been build firstly. It uses the commercial finite element package ANSYS to calculate the electromagnetic and stress-strain fields, and the commercial finite volume package FLUENT to calculate the magnetic driven fluid flow, heat transfer and solidification. Simulation of the DC casting and LFEC processes of 0100mm high pure aluminum ingot by using the model, the obtained electromagnetic flux density and cooling temperature curve fall good agreements with the measured results.The effects of electromagnetic field by single or double coil on fluid flow, heat transfer, solidification process and stress-strain field in LFEC processes of φ100mm ingots have been studied and analyzed in details by using the model; A detailed analysis of the electromagnetic field, parameters of electromagnetic and casting process influencing on the physical field 0100mm high pure aluminum ingot in the process of DC and LFEC casting.Results show the following characters:1) Applied in the mold inside and outside coil at the same time, the strong magnetic field intensity in the insulation cap inside and near the mold wall can. Can generate the magnetic field of the coil insulation cap and promote the rapid loss of melt overheating, play the role of pretreatment; coil crystal can play stirring solidification of aluminum melt, and more conducive to the solidification structure refinement; 2) LFEC double coil under the action of the melt pool can occur within the strongly forced convection, completely changed the direction of flow of the melt, the temperature distribution in the molten pool evenly and effectively reduce the sump depth; increasing the flow velocity of the solidification front melt; 3) Double coil under the action of the LFEC process, with the increase of input current, flow rate of melt increases; uniform temperature distribution,950Kisotherms slightly upward; the sump depth; speed melt at the solidification front speed; and the current frequency increases, the flow velocity of melt decreases; the flow speed on the temperature field and solidification front melt effect is not obvious, the sump depth slightly darker; 4) LFEC process under the action of double ring, casting temperature from 973Kto 1013K, heat preservation cap in the high temperature area increased, the flow velocity of aluminum melt increased slightly, the sump depth changed little; the casting speed from 100mm/min to 140mm/min, the range of liquid phase in the mold increases obviously, the flow velocity of aluminum melt increased slightly liquid, hole depth increases, the sump depth from 0.08m to 0.12m.