On material flow behavior, strain energy, and improved surface integrity ratio in subsequent burnishing after turning.

Burnishing is a way to realize surface strengthening by plastic deformation behavior. How to characterize the severe plastic deformation in subsequent burnishing process and how to make the severe plastic deformation more reasonable and effective for the improvement of machined surface integrity have become key problems. This work studied the relationships among plastic deformation behaviors, strain energy, and improved surface integrity ratio in subsequent burnishing with different initial surface conditions. To achieve this purpose, a numerical strain energy model was first established and then utilized to analyze the material flow behaviors and plastic deformation mechanism. The results indicated that the strain energy density decreases first and then increases, while the strain energy and corresponding energy efficiency gradually increases with the increase of turning feed, i.e., surface residue. As a result, the plastic deformation in subsequent burnishing first increases and then decreases with the increase of surface residue and reached the severest when the turning feed is 0.35 mm/r. Even though the turning-induced surface integrity can be further improved by the subsequent burnishing, the improved surface integrity ratio showed a downward trend with the increase of the turning feed, which ever increased the machining efficiency for the process chain. It is expected to improve both the energy efficiency ratio and improved surface integrity ratio, so as to improve the sustainability of the subsequent burnishing process. [ABSTRACT FROM AUTHOR]