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.

摘要

这项研究涉及沉积在钢上的许多表面硬化铁基合金的摩擦学性能。这种表面硬化的目的是延长挖掘机铲斗的地面接合部分的寿命。这些零件在使用期间会经历机械动作，例如低应力刮擦，高应力切割/打滑，疲劳，冲击，磨损等。结果，挖掘机铲斗的零件在复杂的磨损机制的驱动下遭受了广泛的磨损。在这项研究中，覆盖层是使用手动金属电弧焊沉积的。分别使用光学显微镜，X射线衍射仪和硬度计对沉积物的微观结构，相结构，硬度和残余应力进行了表征。硬面合金的摩擦学性能是使用圆盘球试验进行评估的，干砂砂轮测试和专有的冲击磨损测试。观察到，含有16wt。％的铁基合金在磨损中的材料损失。铬％显着低于常规用于挖掘机铲斗的铬。还讨论了每种情况下的沉积物的冶金学方面和磨损机理。