Tribological Aspects of Metal Cutting

The machining of metals presents a unique tribological situation in which atomically clean, metallic surfaces are cleaved from the interior of the workpiece and maintained in a condition of nearly 100 percent real area of contact with the tool surface during sliding. The conditions of high pressure, high temperature, and essentially uncontaminated contact during sliding create a highly ideal tribological system for analysis. As compared to conventional sliding wear, the analysis of which is complicated by multiple passes of the counterface materials and various forms of contamination and surface reaction, the predictive modeling of tool wear has achieved somewhat greater, if still modest, success. Current models of cutting tool wear are assessed with regard to their usefulness in developing quantitative analytical methods for designing new tool materials and for selecting optimum tool materials under variations in cutting conditions. Approaches which predict the relative wear resistances of potential tool materials from the physical and chemical properties of the tool-work-piece system, without recourse to calibration tests for each system, are emphasized.