Effects of intermittent cutting behavior on wear characteristics of alumina abrasive wheels during grinding ultra-high strength steels

Ultra-high strength steel was increasingly utilized in aero-engine transmission systems due to its exceptional hardness and strength. However, the high hardness and wear resistance of this material could accelerate the wear rate of alumina wheels, ultimately reducing surface finish and geometric accuracy during machining processes. In this case, the ultrasonic vibration-assisted grinding (UVAG) process was proposed to achieve the high performance machining requirements. In this paper, comparative trials were conducted to evaluate wheel wear when grinding ultra-high strength steels using conventional grinding (CG) and UVAG processes with different alumina abrasive wheels, including white alumina (WA) and microcrystalline alumina (MA) wheels. Characterizations of wear performances, such as grinding forces, force ratio, surface morphology of alumina wheel, wear properties of abrasive grains, and ground surface morphology, were elaborated. Results indicate that the contact-separation characteristics of UVAG can modify the trajectory and mode of abrasive cutting workpiece material, resulting in variations in grinding force and force ratio during the process of alumina wheel wear. The morphology evolution of grinding wheel during wear is modified by UVAG, leading to a reduction in severe adhesions and agglomerated wear chips. UVAG induces more abrasive grain fracture in the grinding process, generates additional grinding edges, and sustains the grinding performance of both alumina grains and wheels. Meantime, in comparison with WA wheels, MA wheels do not experience chip clogging or abrasive macro-fracture after prolonged UVAG grinding. This is attributable to the hardness and self-sharpening properties of MA grains, which produce sharper grinding edges, reduce grinding force and chip width, and prevent wear chips from adhering to or accumulating in pores.