Physical modeling of filtration processes of heat-resistant nickel alloys during casting in a vacuum induction installation

The article considers issues related to the efficiency of metal melts’ filtration depending on the size of non-metallic inclusions, parameters of ceramic foam filters and their location options. Studies of influence of the main structural elements on the filtration processes of nickel melts during casting in a vacuum induction installation were carried out on low-temperature physical models. Modeling of melt filtration processes is based on the hydrodynamic similarity of the processes of motion of melt flows and nonmetallic inclusions in casting tanks. A modeling technique has been developed, the scale has been determined and a model installation has been made. Influence of the arrangement of filtration and dividing walls on the dynamics of metal flows, non-metallic inclusions and filtration efficiency is considered. The efficiency of nickel melts filtration is described depending on the technical parameters both on the filter itself (effective filtration surface, filter thickness, channel dimensions, number of channels per unit area), as well as on the type and size of non-metallic inclusions, design features of the casting device and filter layouts. It was found that the overall filtration efficiency is influenced by the rate and uniformity of the melt flows’ distribution in front of the filter. To ensure uniform distribution of the melt flow rates, a dividing wall with bypass holes is installed in front of the filter, the location of which and their number was also the subject of research. As a result of the studies, the relationships were established between the filtration efficiency, the size and type of non-metallic inclusions when using vertical and horizontal foam ceramic filters during the casting of nickel melts in an intermediate casting tank of a vacuum induction installation. It was found that with a vertical arrangement of the filter, its efficiency is higher than with a horizontal one. An additional means of increasing efficiency of the filtration system is the use of a dividing wall. The optimal number of holes and the location of the baffle in the casting tank were determined, ensuring a uniform distribution of melt flows along the height in front of the filter and an increase in its operation time.

filters, physical modeling, fluid flow dynamics of a melt, non-metallic inclusions, filtration efficiency

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