Research on surface integrity of GH4169 machined by ultrasonic assisted grinding

Experiments of GH4169 ultrasonic assisted grinding and conventional grinding were carried out to study the effects of ultrasonic vibration and grinding parameters on microhardness, residual stress and microstructure for the purpose of studying the effect of ultrasonic assisted grinding on the surface integrity of GH4169.The results show that work hardening and residual compressive stress are produced in the surface layer after grinding, and the grain refinement layer is formed.Compared with conventional grinding, ultrasonic assisted grinding can increase the microhardness of the surface layer, as well as the residual compressive stress and the thickness of grain refinement layer.With the increase of grinding wheel speed, the maximum microhardness first decreases and then increases, meanwhile, the residual compressive stress and the thickness of grain refinement layer increase.With the increase of grinding depth, the maximum microhardness, the residual compressive stress and the thickness of grain refinement layer all increase.The change trend of dislocation density is consistent with that of microhardness.