What type of indication would not break over the part edges during visual testing?

The type of indication that would not break over the part edges during visual testing is grinding cracks. Grinding cracks are typically associated with the surface of a part that has been subjected to grinding operations. These cracks tend to remain confined to the surface layer of the material and do not extend into the edges or across surfaces of the part. As a result, they are more likely to show as fine lines that do not cross over edges, making them distinct in appearance during inspection.

In contrast, inclusions, porosity, and quench cracks can manifest in ways that may affect part edges. Inclusions are foreign materials trapped in the matrix and can cause defects extending across the surface. Porosity involves small holes or voids within the material, which may also be located at the edges. Quench cracks typically form due to thermal stress and can propagate across surfaces, including the edges of a part. Thus, these types of indications can cross over edges, whereas grinding cracks do not.