Experimental Study on Dry Sliding Wear Behaviour of Sintered Fe-C-W P/M Low Alloy Steels

Abstract

Powder metallurgy (P/M) manufacturing process is one of the rapidly emerging fields and has extended the applications in aerospace, automotive, manufacturing industries replacing all traditional methods of metal forming operations because of its less energy consumption, maximum material utilization, low relative material wastage, low capital cost. Unlike wrought materials, wear behaviour of porous materials is different and is influenced by the pores present in the materials. The presence of pores leads to weakness and also acts as origin of crack initiation in sintered materials. The present investigation is made to study the dry sliding wear characteristics of P/M Fe-1% C-1%W low alloy steel with different densities (85%, 90%, 95%), as they find several applications in manufacturing industries, particularly in automobile industries. The wear behavior of the as-sintered preforms were studied under dry conditions on pin-on disc arrangement (ASTM G99) against EN 38 steel disc of Hardness HRC 60 with a sliding speed of 2 m/s and at a normal loads of 30, 50, 70N respectively. Wear regimes of P/M steels has been characterized using optical microscopy. From the microstructure of wear pattern it is evident that, presence of carbides of the carbide forming elements W offers greater wear resistance. The elements gets embedded as hard particles in a soft matrix of Fe- C, resulting in non-uniform wear pattern in higher density preforms (95%), whereas uniform wear was observed in low density preforms (85%) even at higher loads during the test. Delamination is a common wear mechanism found in both P/M alloy steels with an increase in applied load, but oxidation wear was observed in all the preforms at low levels of applied load.