Orthogonal turning of AISI 310S austenitic stainless steel under hybrid nanofluid-assisted MQL and a sustainability optimization using NSGA-II and TOPSIS

AISI 310S austenitic stainless steels are widely used in many industries, such as oil, gas, and petrochemical industries containing hot concentrated acids, due to their superior properties like corrosion resistance, high-temperature service, and creep resistance. However, a study on the machining of AISI 310 stainless steel has not been published in the scientific literature. It is known that the machinability of the austenitic stainless steel alloys, in which the AISI 310S alloy is included, is poor due to its low thermal conductivity, high work hardening, and built-up edge (BUE) formation. This situation causes sustainability problems by increasing the energy consumptions, the total machining cost and the amount of carbon emissions. The presented study investigated for the first time machining response and sustainability assessment in the orthogonal turning of AISI 310S stainless steel using three different cutting speeds and feed values, and five different cutting conditions such as dry, vegetable-based fluid minimum quantity lubrication (MQL), nano molybdenum disulfide (nMoS2) reinforced nanofluid MQL, nanographene (nGP) reinforced nanofluid MQL, and nMoS2/nGP reinforced hybrid nanofluid MQL, and a sustainability optimization was performed. Sustainability optimization was conducted to minimize the resultant force, surface roughness, carbon emission, and total machining cost using multi-objective optimization with NSGA-II (Non-dominated Sorting Genetic Algorithm II) and multi-criteria decision-making with TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution). The resultant force, surface roughness, total carbon emission, and total machining cost were reduced by a significant, 56.8%, 86.8%, 30.4%, and 2.9%, respectively, under the nGP reinforced nanofluid MQL cutting condition compared to the dry cutting condition. As a result of sustainability optimization, the use of high cutting speed (220 m/min), low feed values (between 0.11 mm/rev and 0.14 mm/rev), and nGP reinforced nanofluid MQL method (N2-MQL) in the turning of AISI 310S stainless steel material provides the optimum surface roughness values, cutting forces, carbon emissions, and total machining costs.