A Methodology for Tribo-Mechanical Characterization of Metallic Alloys under Extreme Loading and Temperature Conditions Typical of Metal Cutting Processes

Abstract

The present paper proposes a combined tribo-mechanical methodology for assessing friction under conditions representative of metal cutting, without resorting to machining process monitoring. The purpose is to withdraw the size effect’s contribution due to tool edge radius to the well-known overestimation of the friction coefficient. Comparative numerical analysis of several tribological tests led us to conclude that the ring compression test is one of the most suitable for reproducing the frictional conditions at the chip–tool interface. Two distinct metallic alloys were selected to demonstrate the application of the proposed methodology (UNS L51120 lead alloy and 18Ni300 maraging steel in conventional and additively manufactured conditions). The results help to better explain the influences of process parameters on the friction coefficient value under high temperature and high strain rate conditions. Results showed a typical increase in the coefficient of friction of up to 20% due to both temperature and strain rate parameters for 18Ni300. The results are of interest because they allow considering potential sources of error in the numerical simulation of metal cutting when the same friction coefficient value is considered for a wide range of cutting parameters.