Hard turning performance assessment of AISI D2 steel under dual nozzle MQL assisted ZrO2 and GO nano-cutting fluids: A sustainability approach

"Green manufacturing" is often referred as a sustainable manufacturing process where ecofriendly cutting fluids are used to achieve social, economic, and environmental goals, which mitigates the soil, air, and water contamination and enhances operator's health and safety. In this current study, mineral oil based ZrO2 and GO nano-cutting fluids are utilized for the cooling and lubrication purpose during the machining of hardened AISI D2 steel (55 +/- 1 HRC). Machinability characteristics such as tool wear, surface roughness, cutting temperature, power consumption, and the span of the tool has been investigated in this study along with the sustainability aspects such as machining cost, carbon, and noise emissions during the machining process. Machining under GO nano-cutting fluid coupled with dual nozzle assisted MQL outperformed other environments such as ZrO2 NFMQL, pure mineral oil MQL and dry conditions in all aspects. The maximum tool life was achieved under GO NFMQL condition as 136.16 min followed by 94.41, 65.52, 20.58 min under ZrO2 NFMQL, pure oil MQL, and dry conditions. A substantial impact has been noticed on the cost savings under GO-NFMQL condition and cost saving have been reduced by 2.07%, 5.19%, and 5.48%, compared to ZrO2-NFMQL, MQL and dry environments respectively. Further, GO NFMQL environment performed better in both machinability and sustainability aspects than other environments as it gets the highest score of 11 in Pugh matrix sustainability assessment approach.