Abstract:The effects of a variety of factors impacting the solidified structure of aluminum alloy ingot, which included the component and the variety of metal melt, the ultrasonic parameter and the position of probe, the shape and the volume of mould, were discussed on the conditions of ultrasonic transmission where the probe was from the metal melt top. The mechanism of ultrasonic refinement was also discussed. The results indicated that the ability of refining metal ingot by ultrasonic vibration related to the component of metal or alloys itself. With the increase of ultrasonic power and ultrasonic duration, the equiaxed grain occupancy increased until it reached a certain peak value. In order to obtain the better refinement effectiveness, the position of an ultrasonic probe should be at the symmetry center of melt and has a small inserted depth. There are optimum D/H ratios for different volumetric casting mould.