Effect of High Energy Shot Peening on Properties of Stellite 6 Layer Coated on AISI 316 Using Electro-Spark Deposition

Stellite-6 alloy was deposited on a SS316 stainless steel substrate by Electro-Spark Deposition; subsequently, the thickness of deposition layer was around 100 ± 10 micron. High Energy Shot Peening process was applied to improve coated layer properties. Microstructure, chemical composition, micro hardness variation in cross sections, wear properties and visual check for discontinuities of coated layer were studied by employing Field Emission Scanning Electron Microscopy, Optical Microscopy, EDS line scan and pin on disk wear test, before and after the high energy shot peening process. The results show decreasing the surface roughness from 14 to 4.5 micron and improving the micro-hardness of coated layer from 450 to 540 HVN due to High Energy Shot Peening process on the Electro-Spark Deposition coated layers. On the other hand, the wear properties of the coating are improved, the number of defects such as porosities is reduced, and micro-cracks and defects in melts are healed due to compressive residual stress and severe wax deformation.