OBRABOTKAMETALLOV Vol. 26 No. 4 2024 TECHNOLOGY friction. Over the past decade, studies have shown higher machining performance using nanofl uids under MQL conditions [16–19]. However, very few attempts have been made to process Al6061-T6 alloy by roller burnishing using nanofl uid under NFMQL process conditions. From this point of view, this study comparatively evaluates the roller burnishing of Al6061-T6 alloy in dry and nanofl uid conditions under MQL cutting condition. The study evaluated, simulated and optimized the microhardness, roundness and surface roughness by considering the factors such as cutting speed, feed and number of passes. Mathematical models for predicting the surface roughness, microhardness and roundness error were developed based on the experimental results. The chemical composition of the material, conditions of the forming process and details of the roller burnishing tool are presented in the next section. The third section discusses the development of experimental-based mathematical models for predicting the surface roughness, microhardness and roundness of burnished workpiece under both cooling conditions. In the fourth section, the parametric eff ects of roller burnishing on the responses namely surface roughness, microhardness and roundness of roller burnished workpiece under both cooling conditions are comparatively discussed. Then, the optimized process parameters for minimum surface roughness and better microhardness and surface roundness for both cooling conditions are presented. Finally, the important results of the present study and the scope for future research in this area are presented. Materials and Design This study uses aluminum alloy 6061 (Al6061-T6), which is often used for general purposes. Due to its strength-to-weight ratio, corrosion resistance, and weldability, this alloy is popular in manufacturing processes and is suitable for various structural components. It is a precipitation-hardening aluminum alloy. The two most important components are silicon and magnesium. Weldability is the main advantage of aluminum alloy 6061. The aerospace industry often uses aluminum alloy 6061 due to its exceptional strength and light weight. Due to its composition, it can also be used for automotive and marine parts. The selected specimen has a diameter of 30 mm and a length of 50 mm across all surfaces. Table 1 shows the characteristics and chemical composition of aluminum alloy 6061. Ta b l e 1 Chemical composition of Al6061-T6 alloy Element Al Cu Cr Mg Mn Si Zn Fe Ti Percentage 95.8 0.15 0.2 1.1 0.15 0.75 0.25 0.19 0.15 A single-roller burnishing tool with a carbide roller was used in this study. The carbide roller burnishing tool is versatile and can be used on a variety of machines for diff erent applications. Its ability to restore and extend the tool life makes it a cost-eff ective solution for achieving high-quality surface fi nishes. The carbide roller is springloaded in both axial directions to maintain proper pressure throughout the burnishing process. By regrinding or lapping the worn carbide roller, it can be restored and its service life can be extended. The carbide roller tool can be used on CNC lathes, turret lathes or conventional lathes and is suitable for all external surfaces of shafts, tapered shafts, radii, shoulders, etc. Burnishing of the machined surface is possible up to 0.1–0.2 μm. Fig. 1 shows the burnishing tool used in this study. Fig. 1. Roller burnishing tool used in the present study
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