The role of surface energy of adhesion in metal working

• Publisher: Elsevier Science
• Year: 1968
• Weight: 139 KB
• Volume: 1
• Category: Article
• ISSN: 0041-2678
• DOI: 10.1016/s0041-2678(68)80746-8

✦ Synopsis

Frictional behaviour of lubricated roiling-contact elements. Proceedings of the Institution of Mechanical Engineers, 181, Part 1,No. 16 (1967) A rig is described for the study of force systems between rolling steel surfaces which under Hertzian load form fiat circular contact surfaces. The rig is used to investigate the behaviour of contacting bodies rolling in the presence of a lubricant and with a small degree of relative slide between the surfaces. Transitions from boundary to partial elastohydrodynamic lubrication have been observed and the transition from one type of lubrication to the other is marked by changes in the frictional behaviour of the system. These changes in behaviour are related to conductivity readings taken across the contact and it can be shown that the ratio of measured voltage across the contact to the agplied voltage is a measure of the frequency at which surface asperities come into contact. Treating the ratio as a cumulative distribution function shows that two distinct populations exist and the point at which transition from one population to the other takes place corresponds to the transition from partial to full lubrication. The role the surface asperities play in relation to the oil-film thickness can clearly be seen in these experiments. (Tribology 1968