In an aluminum casting, linear indications around the base of a thin section are typically referred to as:

In aluminum casting, linear indications around the base of a thin section are specifically referred to as hot tears. These indications are formed when metal contracts or shrinks as it cools and solidifies. If the metal cannot flow to accommodate the shrinkage, it can lead to cracking along the thinner sections, resulting in elongated linear defects that resemble tears. This issue is particularly common in areas of complex shapes or geometries where stresses are concentrated.

Hot tearing is a critical concern during casting because it indicates a failure in the integrity of the cast part, which can lead to significant performance issues in the final product. Understanding this type of defect is essential for proper inspection and ensuring that the casting process is optimized to minimize risk.

The other options refer to different types of defects that can occur during aluminum casting but do not accurately describe the linear indications specifically observed as hot tears.