Static friction measurements on steel against uncoated and coated cast iron

Authors

• P. Andersson VTT Technical Research Centre of Finland
• L. Kilpi VTT Technical Research Centre of Finland
• K. Holmberg VTT Technical Research Centre of Finland
• A. Vaajoki VTT Technical Research Centre of Finland
• V. Oksanen Tampere University of Technology, Department of Materials Science

Abstract

Static friction is a phenomenon we may mainly consider as related to frictional joints within static
mechanics. The step from static friction to tribological phenomena is, however, rather short, since at the
onset of sliding in a mechanical contact, the static friction determines the initial resistance against motion.
Static friction furthermore plays a role in contacts subjected to traction and fretting. Although being a
phenomenon of short duration, the tribological phenomena during the transition from static friction to sliding
friction may be of great importance for the operational life of the contact surfaces, particularly if the
procedure is repeated for a sufficient number of times.

The present paper describes the principles of static friction measurements, details of the employed static
friction tribometer and the results of measurements with unlubricated and lubricated sliding couples
consisting of steel against uncoated and coated cast iron.