Introduction of compressive residual stresses by Hammering Turning

The process combination of Hammering Turning is an advanced development of vibration-assisted machining (VAM), which integrates a combination of microtexturing of the surface and mechanical surface treatment into the machining process. This investigation compared the process combination of Hammering Turning with conventional turning and single-axis vibration-assisted machining. In the Hammering Turning process, a two-axis vibration is superimposed on the cutting tool in an external longitudinal turning process, which is synchronized in both axes and with the cutting speed. This hammer-like movement of the cutting tool induces a deep plastic deformation of the surface layer, which in turn causes the introduction of compressive residual stresses.
This work investigates the influence of the process parameters feed rate, frequency, and amplitude of the Hammering Turning on the compressive residual stresses in the surface layer. The compressive stresses introduced by Hammering Turning are compared and correlated with those of a conventional turning process and a modified single-axis vibration-assisted machining.
The results show that Hammering Turning can achieve comparable compressive residual stresses of σ < -1100 MPa for conventional mechanical surface treatment when machining AISI 4140 quenched and tempered steel.