After molten metal is poured into a mold, a series of events takes place during the
solidification of the metal and its cooling to ambient temperature. These events
greatly influence the size, shape, uniformity, and chemical composition of the grains
formed throughout the casting, which in turn influence the overall properties of the
metal. The significant factors affecting these events are the type of metal, the thermal
properties of both the metal and the mold, the geometric relationship between
volume and surface area of the casting, and the shape of the mold.