OBRABOTKAMETALLOV Vol. 26 No. 4 2024 TECHNOLOGY was 1:1.5. To improve stability, a surfactant, sodium dodecyl benzene sulfonate (10 % load of nanoparticles), was added to the base oil. A total of six hybrid cutting fl uids of 100 ml (0.4 %, 0.8 %, 1.2 %, 1.6 %, 2 % and 2.4 %) were created by varying the weight concentration of the hybrid nanoparticles in the fl uid. A homogeneous mixture was obtained by magnetic stirring for one hour and ultrasonic stirring for two hours. The stability of the hybrid nanofl uid was evaluated using conventional sedimentation methods. All the hybrid nano cutting fl uid (HCF) samples were collected in 10 ml measuring jars and kept frozen for 72 hours before being used. The specifi c heat capacity and thermal conductivity were measured using diff erential scanning calorimetry and a Pro thermal analyzer, respectively. A rheometer (manufacturer Anton Paar) was used to measure the viscosity of the developed nanofl uid. Three independent tests were conducted, the results of which were averaged to determine the viscosity. To study the tribological properties of HCF, pin-and-disk tests were carried out. Diff erent weight concentrations of CuO/Al2O3 in corn oil were investigated tested using a pin-on-disc tester. Corn oil was preferred as the base for the preparation of nanofl uids due to its availability, costeff ectiveness and desirable thermal properties. Corn oil is a common vegetable oil with good thermal stability and moderate viscosity, making it suitable for dispersing nanoparticles and improving the heat transfer properties of nanofl uids. According to ASTM G 99, a maximum load of 200 N and a rotation speed of 2,000 rpm were allowed during the friction test. To determine the friction coeffi cient using the pin-ondisc setup, a pin is applied to a rotating disk under controlled conditions to measure the frictional resistance between the two surfaces. The approach used in this study is shown in Fig. 1. The turning experiments were carried out using the center lathe machine (Turn-master-35) shown in Fig. 2 with the feed rate of the prepared cutting fl uid (CuO/Al2O3) of 10 ml/s. The SS 304 alloy workpiece with a length of 200 mm and a diameter of 50 mm was machined using the SNMG120408 NSU (coated carbide) tool. The cutting parameters were selected according to the manufacturer’s recommendations for the tool and workpiece. The detailed information of the experimental setup is given in Table 1. The cutting speed, feed, and depth of cut were fi xed at 1,000 rpm, 90 mm/rev, 0.15 mm, respectively. During the turning process, the cutting force, tool tip temperature, and machined workpiece’s fi nish were measured using a piezoelectric dynamometer, digital pyrometer, and surface roughness tester, respectively. The tool fl ank wear was measured using an optical microscope. Table 2 shows the process parameters and MQL environment. Fig. 1. Experimental methodology
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