Investigations on Dry Sliding Wear Behaviour of Sintered/Extruded P/M Alloy Steels (Fe-C-W-Ti)

Abstract

Powder Metallurgy (P/M) is an established manufacturing process allows components of complex geometries with tailor-made strength and high tolerances to be produced in one single operation without subsequent machining resulting in low cost and low environmental impact. Thus, it has replaced all traditional methods of metal forming operations because of added advantages like lesser energy consumption, maximum material utilization, low relative material wastage, and competitive cost. Sintered low alloy steels find numerous applications in making components for machine parts, automobile parts, structural components, etc. Properties and microstructures obtained using P/M that can’t be obtained by alternative metal working techniques. The final density of the sintered P/M parts plays a vital role in determining the component properties and characteristics. In the present study, an attempt has been made to investigate the dry sliding wear characteristics of sintered/hot extruded P/M alloy steels with Fe-1% C as base material, W (Tungsten) and Ti (Titanium) as alloying elements. The wear behavior of the sintered/hot extruded performs were studied under dry sliding conditions on pin-on- disc (ASTM G99) arrangement against EN 38 steel disc of hardness HRC 60 with a constant sliding speed of 2m/s and at a normal load of 30, 50 and 70N respectively. The microstructure and wear regime of extruded P/M steels has been systematically characterized to understand the structure-property relationships using both optical microscopy and scanning electron microscope (SEM). Addition of W and Ti significantly enhances the wear resistance of the extruded P/M plain carbon alloy steel due to the presence of WC (tungsten carbide) and TiC (titanium carbide). The microstructure reveals a combination of Widmanstatten type ferrite on both the extruded P/M steels. Coefficient of friction is slightly higher due to presence of second phase hard WC in tungsten alloyed plain carbon steel. Delaminative wear mechanism is commonly found in both extruded P/M steels with an increase in applied load.