Cold forging tribo-test based on variation of deformation patterns at tool-workpiece interface©

A tribe-test method based on variation of deformation patterns at the tool-workpiece interface is proposed. The deformations were induced by tools of different surface profiles. By this method the influence of tool geometrical features on tribe conditions pertaining to cold forging could be studied under localized rod drawing setup. The adoption of the tools was based on surface expansion evolution at the tool-workpiece interface obtained by finite element simulations of contoured tool indentation and spline forming process. The simulation results showed that the surface expansion distribution varies considerably with change in the tool contour radii, strain hardening characteristics of the parent material, spline module size as well as with change in the tool feed. Using the adopted tools, the performance of several coating-based lubricants was assessed. The performance results demonstrated that with an increase in the degree of local surface expansion, the difference in the effectiveness of each of the lubricants becomes apparent.