Influence of tungsten on dry sliding wear behaviour of sintered/hot extruded P/M alloy steels (Fe-C-W-Ti)

Abstract

In the present scenario, Powder Metallurgy (P/M) is an established manufacturing process used to make components of complex geometries with high strength and tolerances by using incredible materials which are difficult to melt or form by other processes. The mechanical properties and microstructures will determine the component characteristic dependent on the final obtained density of sintered P/M alloy steels. An attempt has been made to investigate the dry sliding wear behaviour of sintered/hot extruded P/M alloy steels with Fe-1C as base material, W (Tungsten) and Ti (Titanium) as an alloying element. The wear test was carried out by using a pin-on-disc tribometer (ASTM G99) against EN 38 steel disc (HRC 60) with a constant sliding speed of 2m/s at normal loads of 30, 50 and 70N respectively. The microstructure of the as-sintered P/M alloy steels reveals the ferritic-pearlite structure whereas for hot extruded alloy steels the microstructure shows a combination of Widmanstatten type ferrite, pearlite and bainite. From the microstructure the presence of WC (tungsten carbide) embedded with Ti in the grain boundaries offers greater wear resistance of the hot extruded P/M alloy steels. The common wear mechanism observed for hot extruded alloy steels is Delamination wear.