An indication that is sharp, half-moon shaped and not deep in an aluminum forging is called what?

The sharp, half-moon shaped indication that is not deep in an aluminum forging is referred to as a lap. This term describes a specific type of surface discontinuity that occurs during the forging process when one layer of material folds over another, creating a defect. In the case of aluminum forgings, laps typically do not penetrate deep into the material, but they present as distinctive, sharp shapes that resemble half-moons.

Laps can occur due to improper forging techniques, such as inadequate material flow or improper die design, leading to surface imperfections. Recognizing the characteristics of laps is crucial in quality control within the manufacturing process because they can affect the mechanical properties and overall integrity of the forged component, even if they may not be structurally critical on their own.

Understanding this defect and accurately identifying it ensures that proper corrective measures can be taken, maintaining the high quality standards expected in metal forging applications.