Quantification of tool wear mechanisms in machining: The case of controlled-microstructure AISI 316L

Tool wear intensity is one of the major performance and economic indicators of metal cutting processes. Understanding and control of tool wear and its governing mechanisms enables effective and sustainable manufacturing. Known wear mechanisms include abrasive, adhesive, chemical and diffusional, where their individual or combined action leads to an overall tool degradation. In this study, we present a methodology for identification and quantification of abrasive, oxidational and diffusional wear mechanisms. Controlled-microstructure AISI 316L stainless steel without and with ceramic inclusions of various hardness (Al 2 O 3 , SiO 2 ) was HIPped to vary the abrasive mechanism. Particle size (3, 10, 15 μm) of the abrasives was also varied. Machining tests with uncoated cemented carbide under high-speed conditions (v c = 150 m/min, f = 0.15 mm/rev, ap = 1 mm) was employed to suppress adhesive wear. Machining in oxygen-free (argon) and oxygen-containing (air) environments was employed to control the oxidational wear mechanism. The results show that abrasive and diffusional wear mechanisms are the most dominant for this tool-workpiece combination. Higher hardness and larger inclusions most negatively impact the tool life, reducing it by 2–3 times. Oxidation and chemical interaction can play a positive role. The observed formation of oxides and (Cr, Fe, Mo) 7 C 3 or (Cr, Fe, Mo) 23 C 6 carbides on the tool surfaces act as a tool protection layers which retard the diffusional processes and improve the tool performance. Abrasive action of the hard inclusions affects both the WC-Co tool itself and the tool protection layers, hence accelerating diffusional wear as well.