Brinelling

Brinelling /ˈbrɪnəlɪŋ/ is the permanent indentation of a hard surface. It is named after the Brinell scale of hardness, in which a small ball is pushed against a hard surface at a preset level of force, and the depth and diameter of the mark indicates the Brinell hardness of the surface. Brinelling is a process of wear in which similar marks are pressed into the surface of a moving part, such as bearings or hydraulic pistons. The brinelling is usually undesirable, as the parts often mate with other parts in very close proximity. The very small indentations can quickly lead to improper operation, like chattering or excess vibration, which in turn can accelerate other forms of wear, such as spalling and galling.