Toward Machinability Improvement of AISI 4340 Using CVD Multilayer TiN-Coated Carbide Insert Through MQL: A Case Study

Sustainability is the approach to obtain overall efficiency in manufacturing by achieving economic, ecological and societal benefits. This experimental research presents a concise comparative investigation on machinability characteristics of high-strength grade hardened steel (AISI 4340) through dry and MQL environments for sustainability. Surface characteristics and machinability studies such as white layer, surface topology, chip morphology, surface roughness and tool wear/tool life were investigated under both the environments. Tool life under MQL is 32.3% higher compared to dry condition at cutting speed of 50 m/min, feed rate of 0.08 mm/rev and depth of cut of 0.1 mm, respectively. In another setting of cutting speed of 100 m/min, feed rate of 0.04 mm/rev and depth of cut of 0.1 mm, tool life under MQL condition is 39.6% more than dry condition. Phenomenon like abrasion, diffusion, notching, chipping and built-up edge is reported as principal wear mechanism. Detailed investigation is still needed for sustainable machining using nano-assisted MQL environments.