Surface quality enhancement of cold work tool steel by GOV (flow peening) process versus abrasive flow machining

Cold work tool steel (DIN 1.2080) has extensive applications such as die and moulds, cutting tools and measuring instruments due to the excellent mechanical features of high abrasion resistance, wear resistance and high strength. Non-traditional finishing processes such as abrasive flow machining (AFM) process is used and also applicable for complex geometries and surfaces. Shot peening process is one of the surface enhancement methods mostly applied to improve the surface strength. The surface quality improvement performance of AFM and surface strengthening capability of shot peening have been combined to obtain a newly developed and patented surface treatment method named as GOV (flow peening) process. In this experimental work, the effects of GOV process parameters (number of cycles, steel ball size, media concentration) on the surfaces roughness, material removal and white layer thickness of DIN 1.2080 specimens which were prepared by wire electric discharge machining (WEDM) were investigated. Consequently, the surface roughness Ra value was decreased from 1.848 µm to 0.498 µm by GOV process with micro-level chip removal of undesired white layer. The material removal was obtained 5.6 mg from the workpiece surface which was supported by the SEM images. From the results, the white layer formed due to nature of WEDM was completely removed from the workpiece surface by GOV process. In the lights of results, GOV process can be used to improve the surface quality by decreasing surface roughness and eliminating the undesired white layer without any excess chip removal.