Gear surface residual stress measurement with ultrasonic wave

Gears are the important part of the mechanical equipment. Residual stress in the process of forging, turning, carburizing and quenching, grinding process seriously influence the fatigue life of gear. The traditional methods are hard to residual stress measurement due to tooth surface complex structures. In this paper, residual stress is measured by ultrasonic method. The longitudinal critically refracted (L_CR) wave is used to measure gear residual stress. We conducted acoustic device design and researched the transmission principle of ultrasonic wave in the gear. It showed that measuring residual stress of the surface of the gear using L_CR waves is feasible.