Cold forging tribo-test based on variation of deformation patterns at tool-workpiece interface (c)

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 geometrica l features on tribe conditions pertaining to cold forging could be studied under localized rod drawing setup. The adoption of the tools was based on s urface expansion evolution at the tool-workpiece interface obtained by fini te element simulations of contoured tool indentation and spline forming pro cess. The simulation results showed that the surface expansion distribution varies considerably with change in the tool contour radii, strain hardenin g characteristics of the parent material, spline module size as well as wit h change in the tool feed. Using the adopted tools, the performance of seve ral coating-based lubricants was assessed. The performance results demonstr ated that with an increase in the degree of local surface expansion, the di fference in the effectiveness of each of the lubricants becomes apparent.