Experimental evaluation of nano-molybdenum disulphide and nano-boric acid suspensions in vegetable oils as prospective cutting fluids during turning of AISI 1040 steel

The present work focuses on the experimental evaluation of the performance of vegetable oil based nanofluids during turning. Nanofluids are prepared by dispersing suspensions of two types of solid lubricants namely, nano-boric acid (nBA) and nano-molybdenum disulphide (nMoS(2)) individually in two vegetable oils which are, coconut oil (CC) and sesame oil (SS). After thorough sonication, the formulated nanofluids are applied as lubricants while turning AISI 1040 steel. The fluids with and without nanoparticle inclusions (npi) are tested for basic properties like flash and fire points, kinematic viscosity, and thermal conductivity. To estimate the performance of nanofluids as lubricants, machining parameters namely main cutting force, cutting tool temperatures, surface roughness, and tool flank wear are measured. Viscosity and thermal conductivity of CC-based nanofluids is found to be better when compared to those of SS. Improvement in machining performance is observed by the application of nanofluids. CC + nMoS(2) at 0.25% and 0.5% npi has shown reduction in cutting forces, cutting temperatures, tool flank wear, and surface roughness when compared to sesame oil based nanofluids. On an average, nMoS(2) suspensions in CC at 0.5% npi have shown 9-13% and 20-25%, reduction in cutting forces, cutting temperatures, tool flank wear, and surface roughness respectively when compared to nBA counterparts in CC and SS at all npi.