Surface Quality Improvement of Aerospace Material of Inconel 718 by GOV (Flow Peening) Process

Inconel 718 superalloy has extensive applications in a variety of industries such as the moulding, aerospace and medical due to its excellent mechanical features such as poor thermal conductivity, high strength at high temperatures and corrosion resistance. However, it is very difficult to process by traditional machining and finishing methods. Abrasive based finishing process is one of non-traditional finishing method applied to complex surfaces. Shot peening process is one of the surface treatment processes mostly applied to improve the surface strength. The superior advantages of these two processes are combined into one process. This newly developed and patented process is called as GOV process. In this study, the effects of GOV process parameters (number of cycles, steel ball size, media concentration) on the surface quality of Inconel 718 already pre-processed by wire electric discharge machining are investigated. The performance parameters are identified as surface roughness, material removal and white layer thickness. Surface finishing with the GOV process improves the surface roughness, Ra value by decreasing from 2.63 mu m to 0.46 mu m by removing micro-level chips up to 10.7 mg which is supported by SEM images. White layer formed due to nature of EDM process is completely removed from specimen surface.