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  • Küçük Resim
    Öğe
    Effects of mono/hybrid nanofluid strategies and surfactants on machining performance in the drilling of Hastelloy X
    (Elsevier Sci Ltd, 2021) Sirin, Emine; Kivak, Turgay; Yildirim, Cagri Vakkas
    This study examined the effects of dry, base fluid, mono and hybrid nanofluid cooling/lubrication conditions on machining performance in drilling of nickel based Hastelloy X superalloys. Nanofluids were prepared by adding 0.6 vol% graphene nanoplatelets (GNP) and/or hexagonal boron nitride (hBN) with or without addition of 0.25 wt% sodium dodecyl sulfate (SDS) and/or gum arabic (GA) as surfactants into the cutting lubricant. Drilling experiment were performed at two different cutting speeds (20 and 30 m/min), two different feed rates (0.04 and 0.06 mm/rev) and a constant drilling depth (13.5 mm). Cutting force, hole quality (surface roughness and de-viations in diameter, circularity and cylindricity), cutting temperature, burr height, tool wear and tool life were selected as the performance criteria. The best results with regard to cutting force, hole quality, burr height, and tool wear were obtained under SDS added hBN/GNP hybrid cutting, whereas the best results for cutting tem-perature were achieved under hBN/GNP hybrid cutting condition without surfactants. In terms of tool wear, after 10 holes under dry cutting, flank wear on the drill was measured as 0.281 mm, whereas after 60 holes under hBN/GNP-SDS cutting condition, it was measured as 0.135 mm. This indicated a 51.96% improvement in tool wear compared to dry cutting. Among the mono nanofluids, the hBN-SDS cutting condition delivered the best performance, whereas among the hybrid nanofluids, the hBN/GNP-SDS cutting performed the best. Finally, evaluation of the surfactants added to the nanofluids revealed that SDS surpassed GA in terms of machining performance.
  • Küçük Resim Yok
    Öğe
    Evaluation of tribological performance of MQL technique combined with LN2, CO2, N2 ecological cooling/lubrication techniques when turning of Hastelloy C22 superalloy
    (Elsevier Sci Ltd, 2023) Sirin, Emine
    Sustainability specifically addresses using ecological cooling/lubrication techniques in the manufacturing industry. Dry, MQL, CO2, LN2, N2, CO2 +MQL, LN2 +MQL, and N2 +MQL techniques were preferred for ecological cooling/lubrication. To determine the effects of cooling/lubrication techniques on machining performance, cutting speed (Vc 80 m/min), feedrate (f 0.12 mm/rev), and cutting depth (ap 0.5 mm) were taken as constants. Cutting tool wear and mechanisms, surface roughness and topography, cutting temperature, and vibration peak values are preferred as machining performance characteristics. At the end of the turning experiments performed with sustainable cooling/lubrication techniques: N2 +MQL hybrid cooling/lubrication technique performed better performance in cutting tool wear (0.226 mm), surface roughness (1.658 & mu;m), and vibration (48.017 m/ sec2), while LN2 cooling technique showed the best performance (87 degrees C) in cutting temperature. Compared to dry condition, the N2 +MQL hybrid cooling/lubrication technique reduced tool wear, surface roughness, and vibration by 73.50%, 53.9%, and 42.4%, respectively.