Numerical Simulation Of Electromagnetic Suspension Continuous Casting Of Magnesium Billets

Electromagnetic suspension continuous casting is a new casting method which includes the virtues of suspension casting and electromagnetic continuous casting.Suspension particles increase the thermal and constitutional undulations and are used as heterogeneous nucleus. which are beneficial to grain refinement.The electromagnetic stirring generated by inductor improves distribution uniformity of suspension particles in the melting alloy.Therefore,the billet quality of electromagnetic suspension continuous casting is enhanced remarkably.It is a new thought to apply this method in the casting process of magnesium alloy,and the study on the electromagnetic suspension continuous casting process of magnesium alloy round billets have been carried out as follows:In this paper,matrix alloy is chosen to be AZ31 magnesium alloy and suspension particles are chosen to be compound of AZ31 and ZrB₂(20%ZrB₂+80%AZ31).The magnesium alloys were manufactured by electromagnetic suspension casting and electromagnetic suspension continuous casting and the microstructures were analyzed.The results showed that smaller grains could be obtained by the both methods,comparing with that by the same casting methods except for adding suspension particles.A mathematical model of the electromagnetic continuous casting process for AZ31 magnesium alloy billets has been developed to predict the temperature in the billet using Microsoft Visual C++6.0 and Finite Difference Method(FDM),which the power of the Joule heating was calculated and incorporated into.The model had been validated by comparing the calculated temperature profiles with the measured temperature profiles.The effect of casting parameters on the on steady-state sump profiles was studied.With the assumption that friction force between mold and solidification shell won't cause drawing breakout,the upper limit of casting speed was evaluated to be 2.75mm/s.The mathematical model of the electromagnetic continuous casting process was utilized to predict the temperature in the billet of electromagnetic suspension continuous casting,after some thermophysical properties were processed.The model had been validated by comparing the calculated temperature profiles with the measured temperature profiles.The effect of amount of suspension particles on temperature field in the billet was studied.The conclusion was drawn that initial temperature of the alloy drops,solidification time of billet shortens, heat-transfer capability declines,comprehensive cooling ability enhances,solidification shell thickness increases,sump depth decreases,initial position of solidification shell enhances and slope gradient of sump profile decreases with increasing the amount of suspension particles.