Tribological behaviour of the hardfacing alloys utilised to fabricate the wear parts of an excavator bucket

Abstract

ABSTRACT This investigation deals with the tribological performance of a number of hardfacing iron-based alloys deposited on steel. The purpose of this hardfacing is to extend the life of ground engaging parts of an excavator bucket. These parts undergo mechanical actions like low stress scratch, high stress cutting/ploughing, fatigue, impact, abrasion etc., during their service period. As a result, parts of the excavator bucket are subjected to extensive wear, driven by complex wear mechanisms. In this investigation, the overlays were deposited using manual metal arc welding. The deposits were characterised by their microstructures, phase structures, hardness and residual stress using optical microscopy, X-ray diffractometer and hardness tester, respectively. The tribological performance of the hard-facing alloys was assessed using a ball-on-disc test, dry sand abrasive wheel test, and proprietary impact wear test. It was observed that the material loss in wear with an iron based alloy containing 16 wt. % chromium is significantly lower than those used conventionally for excavator buckets. The metallurgical aspects of the deposits and the wear mechanisms in each case are also discussed.