A New Machine for Studying Surface Damage Due to Wear and Fretting

Abstract

A test machine was designed and constructed for investigating the effects on wear rate of various parameters such as contact load, relative slip amplitude, and frequency. The test machine consisted of a rigid load frame and a flexible platform onto which specimen coupons were mounted. Vertical wear pads were held stationary in holders that allowed contact between the surfaces of the wear pad and the specimen coupon. Normal contact pressures between the wear pads and the specimen were obtained by using spring-loaded cap screws. The specimen platform was designed to move horizontally at high frequency (100 to 200 Hz) with the amplitude of motion under control. The new test machine allows up to eight specimens to be tested at a time and is extremely useful for statistical investigation of wear behavior in which a large number of specimens is expected to be tested. Tests were performed to study the wear behavior of plain magnesium and magnesium with different coatings against steel. Wear rate curves were presented which were used to compare the performance of the different coatings against wear. This paper discusses the operation and typical results of this unit.