Abrasive wear properties of tool steel matrix composites in rubber wheel abrasion test and laboratory cone crusher experiments

Abstract

Abrasive wear is the most common type of wear phenomenon in mineral crushing industry. Tool steel matrix-based composites are an attractive choice to combat wear in those conditions because of their excellent abrasion resistance. One purpose of this study is to evaluate the abrasion resistance of such composites having different microstructures. Another purpose is to find out whether the simple dry sand rubber wheel abrasion test (ASTM G 65-91), which is a commonly used and relatively cheap and easy-to-perform test, could be used to rank materials for rock crushing although abrasive wear is not the only type of wear in the real rock crushing conditions. For this purpose Nordberg laboratory cone crusher test was used. Seven different composites were studied. The tool steel of type Ralloy ®WR6 was used as a matrix material in all composites. The reinforcement was either cemented carbide (WC–Co), cast tungsten carbide (WC) or titanium carbide (TiC). The composites were manufactured by hot isostatic pressing (HIP). Abrasive wear properties of all the studied composites are very good. The reinforcement type, size, properties, volume fraction and reinforcement distribution in the matrix all influenced the wear results in both of the tests, but in a different way. Best wear resistance in cone crusher conditions was obtained with cemented carbide (WC–10Co) reinforced Ralloy ®WR6 and in dry sand abrasion with WC reinforced Ralloy ®WR6. No simple correlations between the dry sand rubber wheel abrasion test results and the cone crusher test results were found. This can be attributed to the different wear mechanics and consequently wear mechanisms in the two tests. In the dry sand rubber wheel abrasion test abrasion and detachment of the reinforcements are the major wear mechanisms while in the cone crusher abrasion with rock sliding and pure indentation are the major wear mechanisms. The differences in wear mechanisms result from differences in abrasives (type, size and hardness) and other wear conditions. It is concluded that dry sand rubber wheel abrasion test should not be used for screening materials for rock crushing applications as far as metal matrix composites are concerned.