Theoretical calculation and experiment of the surface residual stress in the plane ultrasonic rolling

The service life of the workpiece is largely determined by residual stress on the workpiece surface, which is the most important parameter of anti-fatigue. In order to study the characteristics of residual stress on workpiece surface, the theoretical model of residual stress on the surface of the single impact workpiece is established based on the elastoplastic theory. Subsequently, the relationship between the rolling depth and the rolling force in the plane ultrasonic rolling is established based on the Hertz contact theory, and the contact area coefficient is established to correct the theoretical model. Then, the plane ultrasonic rolling experiments are carried out to validate the model. The results exhibit that the rolling force linearly increases with the increase of rolling depth. The effect of step has a highest relationship with the contact area coefficient, moderate with the feed rate, and minor with the static force. With the increase in static force, the residual compressive stress increased as a whole. The residual compressive stress decrease with the increase in step and the feed rate has little influence on the residual stress. The results reveal that the modified theoretical model can improve the prediction accuracy of residual stress.