The application of flow peening (GOV) process for aerospace materials of inconel 718

Inconel 718 superalloy has extensive applications in a variety of industries such as the moulding, aerospace and medical due to the 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. 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. Considering the advantages of surface quality and strength improvement for abrasive flow machining (AFM) and shot peening respectively, the better advantages of these two processes are combined into one process. This newly developed process is called as flow peening (GOV) process and already patented. In this study, the effects of the GOV process parameters (number of cycles, steel ball size, media composition) on the surfaces of the Inconel 718 already pre-processed by electric discharge machining (EDM) are investigated. The performance parameters are identified as surface roughness, material removal and reduction of white layer thickness. Surface finishing by the GOV process improves the surface quality by decreasing surface roughness, Ra value from 2.63 µm to 0.46 µm and by removing micro-level chips from specimen surface up to 10.7 mg which is supported by the SEM images. It is clear to understand that the white layer is completely removed from the material surface. The flow peening (GOV) process can be used to improve make a better surface quality.