The Changes in Surface Properties During Running-in Process under Rolling/Sliding Condition

Abstract

Changes in surface properties during the running-in process, especially those in surface topography and surface hardness, were examined using a two-disc type of machine. The loads applied were lower than the shakedown limit of a test material. Two differen running-in tests were conducted i. e. a low-speed test in which the in which the contact condition was severe, even at an initial stage, and a high-speed test in which the initial thick oil film thickness became thinner and the contact condition became more severe with time. After running-in, the roughness and correlation distance of disc surface were reduced and increased, respectively. The final surface topography was controlled by the initial surface topography and the final film parameter. The surface hardness was also increased after running-in. Consequently, the scuffing resistance of discs was enhanced through the running-in process. The high speed test was excellent in improving surface topography and increasing surface hardness compared with the low speed test where the wear of rubbing surfaces was increased.