FRICTION AND WEAR BEHAVIOUR OF QUENCHED AND TEMPERED LOW ALLOY STEEL

Abstract

A lot of research has been done on carbon steels and high alloy steels, for improvement of their mechanical and triological properties. Among low alloy steels Cr-V steel, Mn steel, Mo steel were studied for wear resistance applications. Medium Carbon low Cr steel is also very important steel which is used for manufacturing of shafts, gears, axles etc. So this type of steel require to be hard, high strength, and wear resistant. In the present study, medium carbon low Cr steel (C — 0.38 wt. percentage) AISI 5140 group steel, is used under different heat treated conditions, like normalizing, oil quench & tempering, and water quench & tempering. The quenched and tempered steels are the best means for optimizing mechanical and tribological properties. Heat treatment changes microstructure of samples and raise hardness. Study of the morphology of phases in a microstructure and its influence on the friction and wear behaviour is critically important in wear resistant materials. Mechanical and tribological properties of heat treated samples are studied. For tribological study pin-on- disc testing machine is used. Heat treated specimens OE & T and WQ & T shows least wear coefficient and coefficient of friction. During study of wear debris, sub-micron size particles are found (85 to 300nm). Analysis of wear debris gives valuable information about mode of wear, wear mechanisms. SEM micrographs of wear specimen shows, as hardness increases, material loss get decreases.