Investigation of ultrasonic peening technology on the GSH48 graphite steel

In this study, the use of Ultrasonic Peening Technology (UPT) on the of mill rollers graphite steel (GSH48) for enhancement of some of the surface mechanical properties was surveyed. One of the new technologies for severe plastic deformation is ultrasonic peening technology in which vibratory tool strikes the workpiece surface with continual reciprocating motions, resulting in severe plastic deformation on surface. This method improves mechanical properties like hardness, surface roughness, fatigue life and tension strength. With simulation and manufacturing of peening vibratory tool, preparation of process was accomplished including setting up the ultrasonic vibratory tool on lathe machine. The investigation of hardness tests, surface roughness, fatigue and tension strength on the pieces was performed in different conditions, before and after the process of ultrasonic peening with one, two and three passes. The results showed increase of hardness up to %36 in depth of 0.2 mm. Also, the surface roughness was reduced from Ra=1.376 µm to Ra= 0.545 µm. The most improvement in surface roughness and fatigue life was observed at the pieces with three passes of ultrasonic peening.