Effects of Cutting Speed on Chip Characteristics and Tool Wear Mechanisms During Dry Machining of Inconel 718 Using Uncoated WC Tool

The present work deals with tool wear and chip characteristics during dry machining of Inconel 718 using uncoated WC tool. Chip morphology (macro/micro), phenomenon of flank, and crater wear are studied. Effects of cutting speed on cutting force, chip reduction coefficient, approximate temperature generated at the machining zone, and depth of flank wear are discussed. Different wear mechanisms are identified. Abrasion, adhesion, built-up-edge formation, chipping off, grooving, chip welding, and burning are found responsible toward tool wear. It is observed that surface finish of the machined part degrades with increase in flank wear depth. Residuals of Ni, Cr, Fe (major constituents of Inconel 718) are detected through EDS analysis of the adhered chip over the tool surface. XRD analysis also identifies oxides of Fe and Nb present therein. Dry machining condition thus promotes the oxidation of few elements of work material.