Enhancing surface finish through ultrasonic vibration in machining of hardened Mo40 steel

This study examines the influence of ultrasonic-assisted turning (UAT) on the surface finish of hardened Mo40 steel under various cutting speeds, feed rates, and ultrasonic excitation voltages (Vg) at 21 kHz. Compared to conventional turning (CT), UAT improves surface quality most effectively at lower cutting speeds and higher ultrasonic amplitudes. Increasing Vg enhances vibration-induced surface micro-disruptions, producing finer textures and reduced roughness. These benefits are maximized at low-to-moderate cutting speeds and feed rates. Above a critical cutting speed, UAT efficiency declines due to continuous tool contact, causing a slight roughness increase. Optimization identifies an ideal combination of feedrate (0.07 mm/rev), ultrasonic voltage (130 V), and cuttingspeed (27 m/min) for minimal surface roughness. Findings highlight ultrasonic excitation voltages (vibration amplitude) as a key factor in achieving superior surface finish and demonstrate UAT’s potential to enhance machining of hardened steels, offering improved precision and component longevity for industrial applications.