SURFACE ROUGHNESS AND GEOMETRIC PRECISION IN ULTRASONIC VIBRATION-ASSISTED TURNING OF HARDENED 9CrSi ALLOY STEEL

This study investigates the application of ultrasonic vibration-assisted turning (UAT) in machining hardened 9CrSi alloy steel, with a hardness range of 60-62 HRC. The research focuses on the effects of ultrasonic vibration frequency and amplitude on surface roundness and cylindrical accuracy during the turning of a cylindrical workpiece with dimensions of 63[Formula: see text]mm in diameter and 40[Formula: see text]mm in length. A piezoelectric transducer (PZT) operating at a frequency of 28[Formula: see text]kHz and an amplitude range of 5–10[Formula: see text] [Formula: see text]m was employed to generate the ultrasonic vibrations. Experimental results were analyzed using a 2-sample t-test to evaluate the effects of UAT. The findings show a significant enhancement in surface quality, with surface roughness reduced by approximately half compared to conventional turning (0.705[Formula: see text] [Formula: see text]m vs 1.302[Formula: see text] [Formula: see text]m). Additionally, UAT achieved superior geometric precision, with roundness and cylindricity errors reduced by about two-thirds and one-half, respectively, compared to conventional turning (roundness error: 0.00556[Formula: see text]mm vs 0.01361[Formula: see text]mm; cylindricity error: 0.026[Formula: see text]mm vs 0.046[Formula: see text]mm). The ultrasonic vibrations facilitated the formation of shorter, intermittent chips, reducing the risk of surface scratching and contributing to a longer tool life. Furthermore, UAT demonstrated the potential to operate without lubrication, offering both economic and environmental benefits by reducing costs and minimizing pollution. These results highlight the potential of UAT to revolutionize machining processes by enhancing efficiency, precision, and sustainability. However, it is important to note that while UAT shows promising results, further studies are needed to explore its limitations, such as the impact on tool wear over extended periods of use and the scalability of the process for industrial applications.