The Effect of Disc Surface Topography on the Dry Gross Fretting Wear of an Equal-Hardness Steel Pair.

Lenart Lenart,Dzierwa Dzierwa,Pawlus Pawlus

doi:10.3390/ma12193250

Abstract

Experimental investigations were carried out with an Optimol SRV5 tribological tester in a flat-on-sphere scheme. The balls co-acted with the discs in a gross sliding fretting regime. The balls and discs were made from the same steel with a very similar hardness. Tests were conducted at 25–35% relative humidity, 30 °C, and a constant normal load and number of cycles (18,000). The discs had different textures after various machining treatments. It was found that the total wear level of the tribological assembly was proportional to the disc surface amplitude. The influence of the disc roughness on the coefficient of friction was evident only for the smallest stroke of 0.1 mm, and the frequency of oscillation affected this dependency.

Highlights

Fretting is the motion between two contacting parts when the sliding amplitude is small
Fretting regimes are related to the kinds of damage; a material loss occurs in a gross slip, but cracking occurs in a partial slip
When the frequency was set to 50 Hz, COF50-360 characterized the mean and COF300-360 characterized the final friction coefficient

Summary

Introduction

Fretting is the motion between two contacting parts when the sliding amplitude is small. When the amplitude of oscillation is larger than the radius of elastic contact, reciprocating sliding occurs [1]. Depending on the normal load, the following regimes can be recognized when the sliding amplitude increases: stick, partial slip and gross slip [2,3,4]. Varenberg et al [5,6] introduced the slip index, which is a criterion to define various fretting regimes. For a low displacement amplitude, a partial slip occurs. When the sliding amplitude is higher, but smaller than a Hertzian contact radius, a gross slip takes place [7]. Fretting regimes are related to the kinds of damage; a material loss occurs in a gross slip, but cracking occurs in a partial slip. Various types of wear occur during fretting: abrasion, adhesion, oxidation and surface fatigue [8]

Methods

Results

Conclusion