Surface roughness variation in ultrasonic assisted burnishing of high-strength steels

Abstract

Ultrasonic assisted burnishing process is a newly developed alternative of conventional burnishing process that enhances the surface properties of engineering materials. The process needs careful selection of design parameters to improve the quality of surface layer of workpieces made of high-strength steel that are difficult to deform. The analytical models to predict the surface roughness after the ultrasonic assisted burnishing process for surfaces are developed. Feed, ultrasonic influence power and static static force could be considered as main factors influencing to surface roughness at that feed has the greatest impact among other parameters. The models are verified by experimental studies with various ultrasonic burnishing parameters. Technological parameters of the ultrasonic burnishing are found, which decrease surface roughness from 1-2 μm to 0.05-0.55 μm. It is experimentally proved that feed increase results in surface roughness increase. To low the surface roughness of high-strength steel workpieces it is necessary to increase ultrasonic influence power with simultaneous static force lowering. The analytical models obtained in the present work may be employed in determining the best conditions for ultrasonic assisted burnishing in industrial field.

The influence of vibration amplitude on AA7075-T6 corrosion resistance improvement during ultrasonic-assisted burnishing

“…Since the ultrasonic vibration is transmitted into the material structure, it reinforces the mobility of dislocations inside the crystal lattice, reducing the yield strength of materials and producing further plastic deformation in a deeper depth. 37…”

“…According to Table 2, all the UAB parameters, namely, spindle speed, feed rate, force, number of passes, frequency, and ball diameter, were considered constant the same as in previous studies. 30,[37][38][39] The ultrasonic vibration amplitude was varied to determine its impact on the surface roughness and corrosion resistance. Ultrasonic vibration amplitude was measured by a noncontact procedure, utilizing an eddy current sensor made by AEC model PU-05.…”

“…External ultrasonic vibration is transmitted through the structure of the material, reinforcing the mobility of dislocations. 37 This phenomenon decreased the yield strength of materials, promoting more plastic deformation. In addition, ultrasonic vibration applies a higher force on a small zone, causing a remarkable enhancement in surface roughness.…”

“…Therefore, dynamic and static forces simultaneously deform the surface of components to decrease the roughness. 36 Compared to CB, UAB offers further plastic deformation, 37 higher force in a relatively small zone, 38 and lower friction, all of which lead to a noticeable reduction in the surface roughness. Hence, corrosion resistance is expected to be drastically improved due to the UAB-induced smooth surface.…”