THE EFFECT OF SURFACE ROUGHNESS ON SCORING : PART 2 UNDER FLOODED LUBRICATING CONDITION

Abstract

Following the previous paper the authors investigated the effect of surface roughness on scoring in rolling/sliding contact using a two disc machine. Although the lubricating condition in the previous investigation was very severe, i.e. a starved lubricating condition, in this investigation scoring tests were conducted under a mild lubricating condition, i.e. under a flooded lubricating condition. The scoring resistance of carbon steel was also significantly affected by the extent of work-hardening of disc surfaces and the formation of surface films during running-in in the same way as the previous investigation, that is, the scoring resistance of the discs with small roughness showed duality, and on the other hand that of the discs with rough surfaces increased with the surface roughness. Furthermore, it was confirmed that ferrite phase squeezed out on the disc surfaces played an important role in the formation of oxide films, and that the formation of the oxide films was a necessary condition to prevent scoring at the transition temperature of oil.