Influence of surface nanocrystallization on running-in and wearing properties of medium carbon steel

In order to study how running-in affects surface nanocrystallization of medium carbon steel, running-in and wearing tests were conducted, while under lubrication, using a ring-on-disc tester. Variations in the coefficient of friction and multifractal spectrum parameters of frictional vibration signals were analyzed. Wearing behavior of the surface nanocrystallization of medium carbon steel was investigated by examining wearing surface topography. The results showed that the coefficient of friction and the multifractal spectrum parameters of frictional vibration signals are markedly decreased for specimens showing surface nanocrystallization. High surface activity leads to better adsorption of lubricant-on the condition that the load is below a critical value beyond which oil film formation is inhibited. Our test showed that running-in and wearing properties of medium carbon steel can be improved by means of surface nanocrystallization.