Effect of graphite nanoparticles addition into cutting fluid on surface quality and tool wear of 16MnCr5 machinned steel

This article investigates the effect of the addition of graphite nanoparticles with average grain sizes of 400nm and purity of 99.9% in cutting fluid on machining process of 16MnCr5 steel. Machining was performed at three cutting depths of 1, 2 and 3mm and three feed rates of 0.15, 0.25 and 0.35mm/rev using ordinary cutting fluid and cutting fluid containing graphite nanoparticles. Microstructural studies of the machined surfaces, hardness tests from surface toward the center and surface roughness and tool wear evaluations all were implemented in order to evaluate different machinability aspects. Results indicated that, regardless of the depth of cut and the feed rate, using the graphite nanoparticles within the cutting fluid decreased the amount of the tool wear and improved the surface quality of the material due to its effect on decreasing the friction between tool and material, decreasing the generated heat and decreasing the cutting force. The highest and the lowest amounts of cutting tool weight losses were 0.022 and 0.002gr, respectively when using the graphite nanoparticles. In addition, the surface roughness of test pieces decreased from Ra=4.79μm when using ordinary cutting fluid to Ra=3.29μm when using graphite nanoparticles in cutting fluid both in the case of the highest depth of cut and the highest feed rate. Furthermore, microstructural characterizations illustrated that using the graphite nanoparticles resulted in lower microstructural textures, lower work hardening and lower thickness of stress affected layer at the surface of the material.