The mechanism of wear known as scuffing has been a research topic of great interest for many years. However, the question of how scuffing is initiated and the factors that contribute to its occurrence are still poorly understood. In general, it can be said that scuffing manifests itself as the sudden failure of lubricating films in mechanical equipment operating under extreme conditions of load and/or speed. Components such as cams, tappets, gears and piston rings are all prone to scuffing failure. Understanding the mechanisms that initiate failure would enable the development of criteria for scuffing prediction. This paper reviews the numerous scuffing models and theories that exist today and, in doing so, defines the important factors involved in scuffing initiation. Emphasis is given to existing theoretical scuffing models which have been correlated by a wealth of research data obtained from experimental test rigs.

A review of scuffing models

Any rational approach to gear design must consider, as a minimum, the impact of the various modes of gear-tooth failure on gear performance; operating life and reliability; and size, weight, and cost. Gear teeth may fail basically by either strength-related or lubrication-related causes. However, many strength-related failures are influenced by lubrication, or may be induced by lubrication-related failures. This paper emphasizes the principal lubrication-related failure modes of gear teeth, and examines the complex interactions between gear mechanics and gear lubrication in affecting such failure modes. Presented at the 30th Annual Meeting in Atlanta, Georgia, May 5–8, 1975

Gear Failure Modes—Importance of Lubrication and Mechanics

An experiment has been conducted to examine the independent influences of rolling speed and sliding speed on the scuffing of hardened steel discs lubricated by a mineral oil. Both sliding speed and rolling speed have important effects on the scuffing conditions. There is a difference between scuffing conditions at low mean rolling speeds, 0.8 m s−1 or less, and those at higher rolling speeds, 1.6 m s−1 or above. Various criteria for scuffing have been examined. It is possible to define ranges of rolling and sliding speeds over which any one of three of these criteria, total contact temperature, film thickness and friction power intensity, is approximately constant. All these quantities show wide variations outside their respective ranges. Of these criteria, the friction power intensity has the widest range of application. Presented at the 29th Annual Meeting in Cleveland, Ohio, April 28–May 2, 1974

The Effects of Rolling and Sliding Speeds on the Scuffing of Lubricated Steel Discs

Analytical predictive modeling of scuffing initiation in metallic materials in sliding contact

http://ir.lib.ksu.edu.tw/bitstream/987654321/11219/1/%E6%9C%B1%E5%AD%9D%E6%A5%AD_Scuffing+mechanism+during+oil-lubricated+block-on-ring+test+with+diamond+nanoparticles+as+oil+add.pdf

Scuffing mechanism during oil-lubricated block-on-ring test with diamond nanoparticles as oil additive

This paper presents the results of scuffing tests performed with carburized AISI 9310 steel disks and a MIL-L-7808G oil, at a variety of sliding and sum velocities, and with disks ground both axially and circumferentially but with the same composite surface roughness. On the basis of these results, a methodology for correlating and predicting the thermal and scuffing behavior of sliding-rolling disks is suggested. It is demonstrated that the difference between the oil-film temperature at the conjunction inlet and the oil jet temperature, as well as the difference between the disk surface temperature and the oil jet temperature, are basically related to the frictional power loss at the sliding-rolling contact. The scuffing failure results are examined and compared by three different criteria: the critical temperature, the critical frictional power, and the critical frictional power intensity. It is shown that under certain operating conditions the critical temperature and critical frictional power intensit...

H. J. Carper

Papers

Thermal and Scuffing Behavior of Disks in Sliding-Rolling Contact