Lubricated seizure of mild steel observed by X-ray imaging

Abstract

Observation of frictional contacts has always been a problem as the contact is normally hidden. In this work, an X-ray microscope has been used for in situ observation of frictional seizure, wear and interfacial features during the testing of mild steel specimens sliding against an Al alloy 6061 disc. This technique enables the interfacial features of the hidden contact to be observed. Seizure tests were conducted at different sliding speeds of 2, 4 and 5 m/s under lubricated conditions with plain mineral oil. The images obtained during the tests indicated that the X-ray attenuation along its path increased with sliding at isolated locations, due possibly to localized changes in path length or attenuation by the degraded mineral oil. The sliding speed was found to have a considerable impact on the degradation of the oil, which affected the seizure behaviour.