In-Depth Microstructural Analysis of Galling Deformation in Stainless Steels

Galling resistance of different stainless steels was investigated using the ASTM G98 standard. Galling resistance is often only addressed via galling threshold but an increasing number of studies nowadays focus on galling severity. During these studies, three galling categories have recently been identified in stainless steel, based on surface topography evolution, SEM observation, and local chemical analyses. These three categories of galling, namely tolerant, moderate galling, and severe galling have been depicted but still poorly understood. The objective of this work is to determine the relationships between the microstructure, its evolution, and the galling response of the different materials. The authors aim to clarify these relationships and propose an explanation of the consequences of galling on the microstructure of the galled samples. A correlation between the galling severity and the subsurface plastic behaviors is proposed. In particular, the mobility of dislocations in close surface is investigated as a plausible parameter determining galling severity.