Effects of Treatment Duration and Cooling Rate on Pure Aluminum Solidification Upon Pulse Magneto-Oscillation Treatment

Abstract

The effect of pulse magneto-oscillation (PMO) treatment on casting grain size has been widely investigated. Nevertheless, its mechanism remains unclear, especially when PMO is applied at different periods during solidification, namely when only applied above the melting point. In the present work, the effect of PMO treatment applied at different segments during solidification was investigated. It was found that the dendrite fragmentation model may well explain the effect of PMO applied during the dendrite growth stage. However, only the cavities activation model may account for the effect when PMO is conducted above the melting point. In current study, the effect of PMO treatment on grain size was also investigated at various cooling rates. It was established that the cooling rate had only a slight effect on grain size when PMO treatment was applied. Thus, PMO treatment may provide homogeneous grain size distribution in castings with different wall thicknesses that solidified with various cooling rates.

Effect of Coil Configuration Design on Al Solidified Structure Refinement

“…Consequently, slag control and surface examination are more difficult with PMO than that without. Our Previous simulation results showed that magnetic field induced by SPMO tended to cluster near the melt surface and along the mold wall, not at the center of the melt [24,27]. We deduced that if the coil could be given the form of a ring rather than a disc, slag control and surface examination would be much easier.…”

“…The main parameters of PMO, including the peak current, the frequency, and the configuration of the PMO coil, can all be easily adjusted and controlled. Refinement effect was better with higher peak current and lower frequency [19,[21][22][23][24][25][26]. PMO treatment shows great promise in the production of heavy steel ingots on an industrial scale [27].…”

Effect of Coil Configuration Design on Al Solidified Structure Refinement

“…Consequently, slag control and surface examination are more difficult with PMO than without. Our Previous simulation results showed that magnetic field induced by SPMO tended to cluster near the melt surface and along the mold wall, not at the center of the melt [24,28]. We deduced that if the coil could be given the form of a ring rather than a disc, slag control and surface examination would be much easier.…”

Improving the Solidified Structure by Optimization of Coil Configuration in Pulsed Magneto-Oscillation

“…Itzhak et al studied the effect of application of PMO at different stages of solidification and under different cooling rate on both the solidification structure and the recalescence temperature [15][16][17]. Sun et al [18] deduced that the convection in steel melt induced by PMO forced the grains to move from the solid-liquid interface, which resulted in the formation of uniformly distributed dendrites throughout the whole ingot.…”