Synthetic effects of turning and shot peening on surface integrity

Shot peening (SP) is a typically post-machining process, and the surface characteristics resulting from the previous process significantly influence the effectiveness of the SP process, which is determined by microstructure evolution. This study investigates the surface integrity in a multi-process experiment involving turning and shot peening, and the aim is to focus on the impacts of the turning process on the SP. Information about processed surfaces is characterized by corresponding equipment. The results indicate that the differences in surface roughness induced by turning are usually eliminated by SP treatment. Incorrect parameter matching between processes can lead to microcracks on the surface and sub-surface of the material. The final surface information generated by the multi-process is controlled by turning parameters. The reduction in grain size before and after SP is consistent with the observed increase in degree of work hardening (DWH), which is determined by the increment in dislocation density.