Prediction of machining-induced residual stress in orthogonal cutting of Ti6Al4V

In addition to having significant effects on the service life of machined parts, residual stress can cause large deformations during machining of thin-walled parts in aerospace field. The residual stress in machined part surface layer is induced by mechanical and thermal stress in the machining process of parts. Therefore, it is essential to accurately predict the generated residual stress due to the machining process. To address this issue, an improved prediction model of the residual stress for orthogonal cutting process based on analytical method is presented by taking the mechanical and thermal stress into consideration. Oxley's cutting force model and Waldorf's plowing force model are used to calculate the chip formation force and plowing force based on the contact mechanics, Johnson-Cook constitutive model, and slip line theory. The cutting temperature is predicted according to our previous work based on the Huang-Liang model and the Komanduri-Hou model. The final residual stress is predicted by calculating the loading and relaxation of mechanical and thermal stress. The presented prediction method of residual stress is validated by orthogonal cutting of a Ti6Al4V pipe. It is found that the prediction values of the presented model show a good agreement with the experimental results, which indicates that the presented model can be adopted to predict the residual stress of Ti6Al4V during orthogonal cutting.