Effect of roller burnishing process parameters on the surface roughness and microhardness for TA2 alloy

Rolling burnishing is an effective method to improve the surface integrity of the machined part. It not only increases the hardness of the machined surface but also reduces the surface roughness. In this paper, experimental studies are performed to investigate the influence of roller burnishing parameters (i.e., spindle speed, burnishing depth, and burnishing feed) on the surface roughness and microhardness of TA2 alloy. The aim is to model the relations between some relevant process parameters and the surface performances of surface roughness and microhardness after roller burnishing, which can give an optimum combination of process parameters to produce desired surface roughness and microhardness. To achieve this goal, by utilizing response surface methodology and Box-Behnken experimental design techniques, workable empirical models are developed to predict surface roughness and microhardness. Analysis of variance is applied to investigate the relationship between process parameters and the output responses. The validation tests are performed to evaluate the effectiveness of the model and the response surface optimization techniques. The results indicate that the prediction values of surface roughness and microhardness have good agreement with the experimental ones. Among the process parameters, the spindle speed and burnishing depth are the significant parameters for reducing the surface roughness and raising the surface microhardness. Meanwhile, the experimental results also indicate that the roller burnishing process can obviously enhance the surface performances, which can lead to the reduction of surface roughness by 63 % and the increase of microhardness by 28 % compared to pre-machined surfaces.