The improvement of hard facing coatings for ground engaging applications by the addition of tungsten carbide

Abrasive wear is of particular significance in ground engaging applications and increasingly tools are being modified with wear resistant hard facings to extend operational lifetimes. There is a continuous demand for improved performance but without significant increases in production or tool costs. When assessing a new materialʹs performance full scale field trials are both expensive and difficult to perform. This papers presents work on the development of improved hard facing alloys and the parallel development of several laboratory based wear tests in order to simulate, as far as possible, in-field conditions. A hard facing alloy which can be applied to tools as a slurry and then sintered was modified by the addition of hard powder materials has been modified using a range of WC additions. WC powders of differing sizes were added at various levels and the resultant hard facings were characterised in terms of physical properties, microstructure and wear resistance. Wear resistance was measured using several techniques; micro-scale abrasive wear (MASW) using SiC and SiO2 abrasives and rubber wheel tests using sand abrasive in both dry and wet conditions. A correlation between the size of the hard addition and the size of the abrasive particle was observed and significant improvements in wear resistance due to the presence of the WC is demonstrated.