Study on grinding performance during ultrasonic vibration-assisted grinding ultra-high strength steels

Super high-strength steel has an important demand in manufacturing key components inside gear transmission systems of heavy-duty helicopter owing to its superior comprehensive mechanical property. However, the high-performance machining of super high-strength steel is confronted with great challenges owing to the high cutting force, serious tool wear, and impoverished machining quality. Comparative trials in grinding ultra-high strength steel under conventional grinding (CG) and ultrasonic vibration-assisted grinding (UVAG) processes were conducted with white alumina (WA) and microcrystalline alumina (MA) wheels. Grinding performances, including grinding forces, force ratio, ground surface quality, and abrasive wheel morphologies, were discussed in detail. Experimental results show that the separation property between wheels and workpiece in UVAG process contributes to alter the material removal process, reducing the chip clogging and adhesion. In addition, the micro-fracture of abrasive grains can effectively improve the self-sharpening ability of abrasive wheels. UVAG possesses a shorter grinding scratch owing to the ultrasonic vibration than that of CG, which is beneficial to improve machining quality under the same wheel. Meanwhile, in comparison of WA wheels, MA wheels have the narrower grinding marks and better surface quality, which is due to the sharp edges produced by its higher strength, toughness, and excellent self-sharpening.