Residual stress and subsurface damage prediction in tungsten heavy alloy face grinding

Abstract

Residual stress distribution and subsurface damage (SSD) play a crucial role in the fatigue performance and accuracy maintenance of the parts. As a typical two-phase difficult-to-machine material, the two-phase microstructure evolution and damage mechanism of tungsten heavy alloy (WHA) under face grinding have not been fully understood. In this paper, a flow stress model considering grain orientation, grain size effect and dynamic recrystallization effect of WHA was established, and the residual stresses formation during the WHA grinding process was predicted based on this model. A calculation method for determining the depth of the SSD layer based on grain boundary curvature is also proposed, and the relationship between microstructure evolution, formation of SSD, and residual stress under face grinding conditions is discussed. Finally, the proposed model was experimentally verified. The experimental results show that the residual stress on the surface of WHA face grinding is compressive stress, and the value is almost three times larger than that of the conventional grinding method. The results are consistent with the trend of the model, and the prediction error of the residual stress prediction model is about 12 %. The change rule of residual stress and SSD depth with grinding parameters is summarized, which provides a reference for realizing high-precision and high surface integrity machining of WHA and other difficult-to-machine composites.