Tribological Behaviour of En 31 Bearing Steel Against Altin, Alcrn and Crn Coated High Speed Steel

Mechanical parts like bearing in modern machining systems are often subjected to wear and friction causing high heat generation at the interacting zones leading to reduced lifecycle and increased energy consumption of machinery. In this investigation friction and wear characteristics of bearing material EN31 steel against the CrN, AlCrN and AlTiN deposited on high speed steel as counter material is presented. Tribological tests are conducted on a pin on disc tribometer for different combinations of loads, speeds and sliding distances as per L9(34) orthogonal array in dry environment. From the results it is found that tribological characteristics are mainly influenced by Load and speed. Also it is noted that wear rate of contact zone of EN31 with counter material goes on increasing as counter material hardness decreases. Minimum wear for EN31 is found with AlCrN coating. Coefficient of Friction for EN31 steel has been found more for bare HSS then it goes on decreasing as counter material hardness increases. Highest values of tribological characteristics are noted for EN31 steel against uncoated HSS counter material. Machining of composite materials is difficult to carry out due to the reinforcement of highly abrasive constituents in polymer matrix and also because of non-homogeneous and anisotropic structural arrangement of composites. Through this research authors suggested the low cost solution of surface coating on composite machining tools for enhancing the tool life.