Morphological studies and wear behavior of electro discharge coated steel

Abstract

This paper elaborates on the deposition of tungsten and copper (W-Cu) material on the AISI 1020 steel substrate and the method used for deposition with its surface and wear characteristics. The tool electrode used is of tungsten copper (W-Cu) manufactured by powder metallurgy (PM) route with different ratios of tungsten and copper metal powders. The process carried out for deposition is by electro-discharge coating (EDC). In this, the tool electrode material is melted and deposited on the substrate by the application of heat energy due to sparking between the electrode and the substrate. Then a thick layer of W-Cu coating is formed on the substrate material. The substrate material of AISI 1020 steel was cut in cylindrical shapes of 10 mm diameter and height 10 mm by wire cut EDM machine and was then surface grinded for the accuracy and polished surface. The cylindrical size was considered for holding the specimen in the clamping device of wear testing machine easily during wear testing. The wear behavior of the coated samples is assessed by the pin on disc method. The effect of mixing ratio, micro hardness, Scanning Electron Microscope (SEM), Energy Disperse Spectroscopy (EDS) analysis, Coefficient of friction (COF) etc., for different composition coated samples has been investigated. The results show that the micro hardness achieved in the range 51-84HV for coated specimens of W-Cu of different composite substrates. The COF was achieved in the range of 0.16 to 0.31 after wear experimentation. The microstructures of the coated samples are analyzed before and after wear by using SEM and EDS.