Assessing hard-turning performance improvement using ionic liquid-infused cutting fluids: Tribological benefits, tool life assessment, and sustainable machining

Ionic liquids have recently acquired popularity as excellent lubricant additives due to their exceptional tribological and thermal properties. Hard turning of hardened steels (>45 HRC) poses challenges like high cutting temperatures, leading to rapid tool wear and increased costs. This study developed a unique cutting fluid using 1-butyl-3-methylimidazolium chloride ionic liquid in concentrations of 1, 3, and 5 wt.% to improve the machinability of AISI D2 hardened steel (57 ± 1 HRC) with a low-cost CVD-coated carbide tool. Results showed reduced cutting temperature, tool wear, and power consumption. The tool life was 51.5 min for flank wear (VBc = 0.2 mm) and 40 min for surface roughness criteria. Circularity error and carbon emissions were 0.02 mm and 1.827 kg CO 2 , respectively, with a machining cost of $ 0.909 per cut, making it an economical, and environmentally sustainable approach for hard turning.