Scuffing Under Dry Sliding Conditions—-Part II: Theoretical Studies

Abstract

Scuffing of contacts sliding under dry conditions is theoretically investigated. The study is based on the experimental results for scuffing of aluminum/steel and steel/steel contacts tested in air and refrigerant environments. The major focus of the present study is on the material failure leading to the removal of protective surface films and subsequent cold welding. This failure is controlled by the local stresses, temperatures and strains which are estimated with the aid of several models describing surface mechanical and thermal interactions. The existing hypotheses for scuffing are evaluated on the basis of the experimental observations and these theoretical estimates. A new hypothesis for scuffing and its corresponding criterion are proposed. The proposed hypothesis states that scuffing is due to a subsurface failure caused by the initiation and propagation of cracks, removal of portions of the load-bearing surface, generation of large areas of bare metal and, finally, cold welding. It is demonstrated that the proposed hypothesis can explain qualitatively the experimentally obtained results. Although derived from the scuffing behavior of contacts under dry sliding conditions, this hypothesis may have a wider applicability.

Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998

KEY WORDS:

• Scuffing
• Fatigue
• Aluminum

Notes

Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998