Low-frequency pulsations of melt during lost foam casting process: Part I

An investigation into the process of the appearance of low-frequency pulsations of liquid metal in a mold is carried out on the basis of a mathematical model of kinetics of mold filling during the lost foam casting process (LFCP). The mold filling is shown to occur with a delay, when a gas space arises between the material of the lost pattern and liquid metal, which gets a mechanical impulse, causing fluctuations of its level in the riser and pressure in the gas space. The natural frequency of fluctuations in the gas space is shown to decrease (at first abruptly and then slowly) as the mold is filled by metal. At the same time, this depends weakly on the gas permeability of the mold, slightly increasing and then stabilizing as the feed speed of the liquid metal into the mold increases and decreases as the rarefaction in a flask increases.