Abstract:

In this paper,first,the residual stress state of the workpiece surface machined by pre-stress cutting was investigated via the thermo-mechanical coupling analysis. Next,three residual stress types of the machined surface were revealed by overlapping the mechanical stress and the thermal stress distributing on the workpiece surface,and the corresponding formation conditions are also qualitatively discussed. Then,the effects of the cutting edge roundness
and the pre-stress on the residual stress state of the machined surface were further analyzed. Finally,some experiments of pre-stress hard cutting for 40Cr alloy steel with quench hardening were carried out at different cutting edge roundness and pre-stress,and the results were compared with the theoretical ones. It is found that both the value and the distribution of the residual stress depend on the cutting edge roundness,that both the residual compressive stress and the strained layer’s thickness increase with the blunt round radius,that the pre-stress effectively increases the residual compressive stress of the machined surface,but it basically has no influence on the stress distribution,and that the proposed theory is reasonable because the experimental results accord well with the theoretical ones.

Key words: thermal elastic-plastic mechanics, thermo-mechanical coupling, residual stress, pre-stress cutting