What type of defect usually develops due to rapid temperature changes in metal casting?

Shrinkage cracks often develop in metal casting processes due to rapid temperature changes. When molten metal cools, it contracts; if the cooling is uneven or rapid, certain areas may cool and solidify sooner than others, leading to internal stresses within the material. If these stresses exceed the material's tensile strength, cracks may form. This phenomenon can be exacerbated by the material’s thickness and the cooling rate, resulting in distinct and potentially detrimental cracks.

Weld porosity, a result of trapped gas during welding, and laps, which occur when layers of metal do not fuse correctly, are unrelated to temperature changes in metal casting. Core shifts refer to the misalignment of cores in sand casting molds, which is also not a consequence of rapid temperature fluctuations. Understanding these distinctions is crucial for comprehending defects in metal casting and their root causes.