Numerical Simulation On Dual-coil Electro-Magnetic Casting Of 6005A Aluminum Alloys

In order to refine the micro structure of 6005A aluminum alloy,to improve the antisegregation of ingot surface and to avoid the thermal cracks caused by uneven temperature distribution.The method of using double coils and installing partition in the diversion pipe was chosen to do the project.Based on the software of ANSYS,a mathematical model was established to accurately describe the process of dual-coil electromagnetic casting.The distribution laws of electromagnetic field in space and melt was illustrated.By means of fixed variables,the Melt flow and heat transfer laws based on mathematical model of multi-physics field coupled was illustrated relatively accurate.When the current intensity increases from 100A to 400A,the magnetic flux density increases from 0.040T to 0.190T and the electromagnetic force increases by 13540N/m3.When the frequency is increased from 10Hz to 100Hz,the magnetic flux density of the melt decreases from 0.0196T to 0.00259T,and the electromagnetic force of the edge of the ingot increases from 1000N/m3 to 2230N/m3.When the partition and the double coil are used at the same time,the maximum flow velocity decreases from 0.100m/s to 0.085m/s,the depth of the sump decreases from 58.7mm to 56.8mm,and the maximum flow velocity at the solidification front increases from 0.0021 m/s reduced to 0.0020m/s.After installing the partition,the velocity of upper melt surface was reduced from 0.0190m/s to 0.0014m/s.The installation of the guide partition helps to enhance the shearing effect of the electromagnetic field,and avoids the disturbance caused by the electromagnetic force on the upper melt surface,effectively.The temperature is evenly distributed and the grain is refined.The maximum flow velocity was 0.085m/s with the casting temperature increasing from 690℃ to 730℃.The initial solidification position decreased by 3mm.The depth of the sump increased from 56.2mm to 57.7mm.The maximum flow velocity increased from 0.075m/s to 0.090m/s when the casting speed increased from 80mm/min to 120mm/min.The depth of the sump increased from 36.5mm to 78.2mm,which approximated the relationship of linear.The initial solidification point dropped by about 11mm,which is prone to leakage;the maximum of velocity of liquid near solidification front move to the edge of ingot,the shell was thinning.When the dual coils worked together,the effect of the current intensity variation of guide pipe coil on the distribution of macroscopic physics field is obviously higher than that of the mold coil.When the current of the coil increases by 50A,the increase of the velocity of the melt is 0.020m/s,and the current in the mold coil with a 50A increase,the maximum velocity of melt increased by 0.015m/s.When the current of the coil was 100A and the current of the mold coil was 150A,the melt flow rate reached 0.085m/s and the depth of the sump depth dropped to a minimum of 56.9mm.When the frequency changes from 15Hz to 25Hz,the maximum flow velocity increase gap up to 0.025m/s and the sump depth reaches 55.7mm at the frequency of 25Hz.When the frequency changes from 50Hz to 80Hz,the maximum melt velocity decreases,the depth of sump increases 1.1mm.