A Study on Sliding Wear Mechanism of Cu-Be Alloy

Abstract

The author investigated the wear mechanism in the unlubricated sliding wear for Cu-Be alloy combined with the dissimilar metal (carbon steel; S55C) and also the phenomenon of the metal transfer in the adhesive or thermal wear range.
The following fact becomes clear that when BeA-50 (hardness at after aging; H_RC 19-23) is used as a stator, the oxidation caused the main wear at a sliding velocity of 0.05∼0.20 m/sec, under a contact pressure of 5 kg/cm², but in BeA-25 alloy (hardness at after aging; H_RC 38-42), the adhesive phenomenon appears at a sliding velocity of 0.05 m/sec. When the velocity is between the above value and 0.70 m/sec, however, every alloy sufferes a great wear loss owing to the scratching or turning up operation by the adhesive wear marks or the wear debris existing between the sliding surfaces. Besides, the wear resistance in this range is better in BeA-25 alloy with higher hardness. When the velocity is about 4.00 m/sec, the thermal wear occurs and the conspicuous metal transfer as well as the high temperature oxidation was observed; the wear loss was comparatively small.
From the wear tendencies observed under the different wear mechanisms, the following fact becomes clear: in the oxidative wear range, the increasing rate of wear loss is small and the wear loss in the adhesive wear range increases almost linearly in proportion to the increasing sliding length, but in the thermal wear range, the high temperature oxidation and the increasing rate of the wear loss is small.
As the parts generated the metal transfer in the process of wear showed the wear between the metals of same kind, they transfer all the more easilly. Besides, the transfer-metal generated under the high velocity cracked owing to the thermal shock and the diffusion phenomenon between the matrix metals was observed.