ON THE ISSUE OF ALLOY CRYSTALLIZATION DURING CASTING INTO METAL MOLDS

The modern scientific and technological revolution, along with social progress, has ensured tremendous scales of production development in our country. When obtaining many machine parts, instruments, and structures, cast blanks are the most cost-effective option, and in the case of particularly complex parts or when using alloys that cannot be processed by pressure, casting technology becomes the only possible method. At the same time, a significant number of specific defects occur in castings; surface roughness and dimensional accuracy often do not meet the requirements set for products; the properties of alloys in their cast state are generally lower than those in their deformed state. Therefore, the problem of further improving the quality of cast blanks has become critically important today. To address this issue, a specialist must understand the mechanisms of casting processes and be able to control them. The article discusses the physical and mechanical processes that occur during the pouring of molten metal into a metal mold. Various scenarios of premature formation of heterogeneous nucleation sites are considered. The features of nucleus formation on the solid surface of the mold are described depending on its geometric characteristics. Additionally, physical models of crystallization of heterogeneous nuclei are presented, describing the mechanism of appearance of a widespread defect in castings in the form of shrinkage cavities.