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Öğe An attempt towards green machining of Ni-based Hastelloy C4 alloy: Effect of vegetable oils and their combination with TiO2 and SiO2 nanoparticles on outputs(Elsevier, 2023) Yildirim, Cagri Vakkas; Sirin, Senol; Kivak, Turgay; Ercan, Hamdi; Sarikaya, MuratThe importance of nickel-based superalloys has increased day by day due to their use in special applications. However, the difficulties in the machinability of these alloys bring some concerns about parts quality and efficiency. Although researchers have tried ways (such as the use of high-performance cutting fluids) to overcome these challenges, their sustainability is still controversial. Therefore, this experimental research aims to contribute to the sustainable machining of nickel-based superalloys. In this regard, the present study investigates the effectiveness of vegetable-based fluids (sunflower, olive, hazelnut, and corn oils) and nanofluids (SiO2 + sunflower oil, SiO2 + olive oil, SiO2 + hazelnut oil, SiO2 + corn oil, TiO2 + sunflower oil, TiO2 + olive oil, TiO2 + hazelnut oil, and TiO2 + corn oil) during the machining of Ni-based Hastelloy C4 alloy. The study was carried out in three stages. In the first stage, all cutting fluids' pH and thermal conductivity values were measured. In the second stage, machinability tests were conducted under the prepared cutting fluids. Later, friction-wear tests of the cutting fluids that offered the best performance in the previous stage were done. As a result, the pH change was significantly increased with the addition of nanoparticles (TiO2 and SiO2) to corn oil. TiO2 nanoparticles allowed further improvement of thermal conductivity. Compared to dry machining, improvements of 58.57%, 34.88%, 53.18%, and 36.1% in surface roughness, cutting temperature, tool wear, and power consumption were achieved with corn oil+TiO2 nanofluid, respectively. It was determined that adhesion, BUE, BUL, and chipping were dominant damage types. Also, an adhesive is the dominant wear mechanism.Öğe A comparative study on the tribological behavior of mono&proportional hybrid nanofluids for sustainable turning of AISI 420 hardened steel with cermet tools(Elsevier Sci Ltd, 2022) Yıldırım, Çağrı Vakkas; Şirin, Şenol; Kivak, Turgay; Sarıkaya, MuratThe current study examines the influence of various mono and proportional hybrid nanofluids prepared with multi-walled carbon nanotube (MWCNT), alumina (Al2O3) and molybdenum disulphide (MoS2) on the performance of cermet tools in turning of AISI 420 hardened steel. First, mono-nanofluids were prepared using each nanoparticle separately (i.e., Al2O3, MWCNT and MoS2). Afterward, hybrid nanofluids were prepared at three different nanoparticle mixture ratios i.e., particle A:particle B of 1:1 (50 vol% + 50 vol%), particle A:particle B of 1:2 (33.34 vol% + 66.66 vol%), particle A:particle B of 2:1 (66.66 vol% + 33.34 vol%) in a constant volume concentration of 0.6%. Prepared nanofluids (nine different hybrid nanofluids and three different mono nanofluids) were cooperated with the MQL system and their effects on the machinability characteristics such as surface roughness, surface topography, temperature, tool flank wear, and wear mechanisms were investigated. The results were compared with dry and base-fluid MQL assisted cutting results. The surface roughness was decreased by 41.54%, 37.38% and 30.62% through Al2O3:MoS2 (2:1), Al2O3:MoS2 (1:2) and Al2O3:MoS2 (1:1) hybrid nanofluids compared to base fluid, respectively. It was found that different ratios of one more than nanoparticles have a significant effect on the synergistic effect. Based on the all experimental results, it can be concluded that it is necessary to optimize the nanoparticle ratios used in the preparation of hybrid nanofluids.Öğe The effect of nanofluids reinforced with different surfactants on the machining and friction-wear properties of Waspaloy(Elsevier Sci Ltd, 2023) Yıldırım, Çağrı Vakkas; Şirin, Şenol; Kivak, Turgay; Sarıkaya, MuratIn present investigation, a number of experiments were done to determine the impact of surfactants on Waspaloy machining characteristics and the friction-wear behavior on the ball-on-disc tester. The experiments were carried out in dry, base fluid (sunflower oil), Cuo, and ZnO nanofluid conditions with/without surfactant. Four distinct surfactants, including Gum Arabic (GA), Sodium Dodecyl Sulfate (SDS), CeTyltrimethylAmmonium Bromide (CTAB), and PolyVinyl Pyrrolidone (PVP), were employed to prepare the nanofluids with surfactant. In addition, viscosity, pH, and thermal conductivity measurements were made to determine the prepared nanofluid's thermo-physical properties. Tool wear and its mechanisms, surface roughness and cutting temperature in machining experiments, coefficient of friction (CoF), microhardness, and wear track width in ball-on-disk tests were choosen as evaluation criterias. From both the machining and ball-on-disk test results, it was determined that the ZnO + PVP nanofluid condition outperformed the other conditions. The ZnO + PVP nanofluid condition provided 53.9 %, 36.52 %, and 44 % improvement in tool wear, surface roughness, and cutting temperature, respectively, compared to the dry cutting condition. Also, considering the results of the ball-on-disk test, it was found that the CoF and width track width values for the ZnO+PVP nanofluid condition were both 76.02 % and 56.11 % lower than the dry condition.Öğe Effects of hybrid nanofluids on machining performance in MQL-milling of Inconel X-750 superalloy(Elsevier Sci Ltd, 2021) Sirin, Senol; Kivak, TurgayFriction and high temperatures greatly affect machining efficiency when machining superalloy materials. Nanoparticles with high thermal conductivity and lubricity are preferred for increase lubricant performance. Nanofluids prepared with nanoparticles not only reduce environmental concerns but also positively affect the machining efficiency in the sustainable manufacturing process. However, some nanoparticles added in mono form stand out with their thermal conductivity and some nanoparticles with their lubricating performance. For this reason, the lubrication performance of hybrid nanofluids prepared with nanoparticles with different superior properties is a matter of interest. In this study, the machining performance of Inconel X-750 superalloy was investigated by using hexagonal boron nitride (hBN), graphite (Grpt), and MoS2 nanoparticles with different shapes and properties. For this purpose, the milling experiments were performed under three different hybrid nanofluid (hBN/Grpt, hBN/MoS2, and Grpt/MoS2) conditions, at three different cutting speeds (30, 45, and 60 m/min), and three different feed rates (0.05, 0.10, and 0.15 mm/rev). Cutting force, cutting temperature, surface roughness/topography, tool wear, and tool life were selected as machining performance criteria. According to the results obtained from the experiments, it was understood that the hBN/Grpt hybrid nanofluid outperformed hBN/MoS2 and Grpt/MoS2 conditions in all performance criteria. hBN/Grpt hybrid nanofluid achieved 36.17% and 6.08% improvement in tool life compared to Grpt/MoS2 and hBN/MoS2 nanofluids, respectively.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 VakkasThis 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.Öğe Machinability performance of nickel alloy X-750 with SiAlON ceramic cutting tool under dry, MQL and hBN mixed nanofluid-MQL(Elsevier Sci Ltd, 2021) Sirin, Senol; Sarikaya, Murat; Yildirim, Cagri Vakkas; Kivak, TurgayNickel alloy X-750 which is difficult-to-machine material, is employed in many critical fields owing to its superior mechanical and thermal properties. However, these superior features lead to some difficulties in its machinability especially when using carbide tool materials. Hence, ceramic cutting tools (CCTs) having excellent hardness, heat and abrasion resistance, and poor chemical proximity to workpiece material are a perfect choice in machining operations of such materials. Considering this, the current study focused on the influence of various cutting environment, i.e., dry, base fluid-MQL without any mixed nanoparticles (BF-MQL) and hBN dispersed nanofluid-MQL (NF-MQL) on surface roughness, 2D-surface topography, maximum cutting temperature, cutting force, micro-hardness, flank wear and its mechanism when milling of alloy X-750 with Sialon ceramic tools. As a result, surface roughness was reduced by about 39% and 47.2% with BF-MQL (0 vol% additive) and hBN mixed NF-MQL, respectively compared to dry machining environment. Also the noticeable improvement with NF-MQL environment in 2D-surface topography of workpice, cutting temperature and cutting force has been achieved, the dry machining offered less tool wear for CCT than both BF-MQL and NF-MQL.Öğe A new lubrication approach in the SPIF process: Evaluation of the applicability and tribological performance of MQL(Elsevier Sci Ltd, 2022) Sen, Nuri; Şirin, Şenol; Kivak, Turgay; Civek, Tolgahan; Seçgin, ÖmerThe abrupt changes in the customer demands and the need to achieve versatility in production for satisfying the different needs of consumers have resulted in the development of rapid prototyping processes. Single Point Incremental Forming (SPIF) is a forming method which doesn't require dies for production and thus enables to greatly reduce the manufacturing costs for low to medium batch productions while enabling versatile manufacturability. One of the major disadvantages of this process is the poor surface quality of formed parts due to friction between tool and sheet interfaces. For this reason, suitable lubrication techniques and the use of lubricants are of great importance in obtaining the desired surface quality. In this study, the Minimum Quantity Lubrication (MQL) technique, which provides significant improvements in metal cutting processes with its effective lubricating feature, has been applied for SPIF process to investigate its effectiveness in SPIF processes. For this purpose, a series of experiments have been carried out by forming 7128 sheet metals with SPIF process in a CNC vertical machining center. In the experiments, SPIF parameters (feed rate, tool stepdown, etc.) have been kept constant and the effects of MQL parameters on surface roughness/topography, thickness distribution, roundness deviation, angular deviation have been focused. Three different pressures (4, 6, and 8 bar), three different flow rates (50, 75, and 100 mL/h) and three different vegetable-based oils with different viscosities have been selected as MQL parameters. In addition, 7128 sheet metal has been formed with the SPIF process by using a paste lubricant for the comparison of paste lubricated and MQL assisted SPIF process. Finally, friction tests have been carried out in a ball-on-disk device to determine the friction coefficients of the oils. Experimental results have shown that the increase in pressure has greatly increased the surface quality and dimensional accuracy, while the increased flow rate level improved the surface quality and dimensional accuracy up to a certain value (75 mL/h). It has been concluded that the surface quality can be improved by 14.60% with the MQL assisted SPIF process over the paste lubricated SPIF process, which has proved the applicability and superiority of MQL technique for SPIF processes.Öğe Performance evaluation of MQL with AL(2)O(3) mixed nanofluids prepared at different concentrations in milling of Hastelloy C276 alloy(Elsevier, 2020) Gunan, Fatih; Kivak, Turgay; Yildirim, Cagri Vakkas; Sarikaya, MuratSince some deficiencies in mist lubri-cooling techniques i.e., minimum quantity lubrication (MQL) in heavy cutting conditions have been noticed, recently nano-cutting fluids which have enrich thermal conductivity than base fluid, are begun to be used in MQL system. One of the critical issues arising in this process is the addition of the appropriate nanoparticle ratio to the base liquid. Therefore, this study aimed to find the optimum distribution rate of Al2O3 nanoparticles having excellent properties and machining parameters. For this purpose, by adding Al2O3 nanoparticles to vegetable-based cutting fluid, nano-cutting fluids were prepared in different volumetric concentrations (0.5, 1.0 and 1.5 vol%). These prepared nanofluids were used in the MQL system when milling of Hastelloy C276. Three cutting speeds (60, 75 and 90 mirnin) and three different feed rates (0.10, 0.15 and 0.20 mm/rev) were added to the experimental design to study the performance of nanofluids under several cutting parameters. Apart from this experimental design, to clearly see the effect of concentration rates on tool wear and tool life, three experiments were carried out at each concentration ratio by keeping the machining parameters. Eventually, 1 vol% Al2O3 concentration clearly provided an improvement by up to 23% and 10% in tool life, compared to 0.5 vol% and 1.5 vol% concentration, respectively. In addition, while chipping/fracture, attrition wear and peeling of coating were observed under all cutting conditions, there was no evidence for workpiece material adhesion at 1 vol% and 1.5 vol% Al2O3 based nanofluid-MQL. (C) 2020 The Authors. Published by Elsevier B.V.Öğe Performance evaluation of whisker-reinforced ceramic tools under nano-sized solid lubricants assisted MQL turning of Co-based Haynes 25 superalloy(Elsevier Sci Ltd, 2021) Sarikaya, Murat; Sirin, Senol; Yildirim, Cagri Vakkas; Kivak, Turgay; Gupta, Munish KumarCeramics are widely used in machining of high temperature alloys i.e., Co-based Haynes 25 alloy due to its superior characteristics. The present paper is focused on the performance of whisker-reinforced ceramic cutting tool (WRCCT) under nano-sized solid lubricants dispersed in MQL (nanofluid-MQL) during turning of Co-based Haynes 25 alloy. The turning experiments were performed under several cutting environments (dry, base fluid MQL (BF-MQL), hBN based nanofluid MQL (hBN-NMQL), MoS2 based nanofluid MQL (MoS2-NMQL), graphite based nanofluid MQL Gr-NMQL) by varying cutting speed (200 and 300 m/min) and feed rate (0.1 and 0.15 mm/ rev) values. Initially, the viscosity and thermal conductivity of nanofluids were evaluated and then the prepared nanofluids were used for machining experiments. The results reveal that the rate of increase in thermal conductivity coefficient relative to base cutting fluid was 11.90% in hBN-nanofluid, 16.29% in MoS2-nanofluid and 14.12% in Gr-nanofluid. In terms of machining performance, on the one hand, the minimum surface roughness was obtained from Gr-NMQL assisted machining, on the other hand, the hBN-NMQL has been successful in limiting of notch wear and nose wear values. Compared to dry turning, the temperature was reduced up to 27.18% with hBN doped nanofluids, while it was 34.95% with MoS2 doped nanofluids and 29.32% with graphene doped nanofluids.Öğe Performance of cryogenically treated carbide inserts under sustainable cryo-lubrication assisted milling of Inconel X750 alloy(Elsevier, 2021) Sirin, Senol; Yildirim, Cagri Vakkas; Kivak, Turgay; Sarikaya, MuratOwing to their superior features even under elevated temperatures, the nickel-based superalloy Inconel X750 is among the materials demanded in many critical areas. However, such alloys are hard to cut because of their characteristic properties i.e., strain hardening, poor thermal conductivity, high mechanical resistance at elevated temperature, the presence of abrasive carbide fragments and chemical proximity. Therefore, it is important to develop the machinability characteristics of these materials with sustainable machining methods that offer high performance. For this, in this work, a number of attempts were made during the milling of the Inconel X750 alloy. During the experiments, the performance of each cutting tool was investigated by considering three different tools which are uncoated carbide tool, cryogenically treated cutting tool and TiAlN coated tool. Since the machinability of superalloys is difficult in the dry environment, three different sustainable cooling/lubrication conditions such cryogenic LN2, MQL and hybrid cooling/lubrication (MQL + LN2) have been used in conjunction with these tools. In evaluating the effectiveness of the employed methods, flank wear, tool damage types, surface roughness/topography, cutting force and maximum temperatures were analyzed. As a result, even if the cryogenically treated tool performed slightly better than those of untreated, it still did not reach the performance level of the TiAlN coated tools. The hybrid cooling/lubrication system with coated tool offered the best solution in terms of all criteria. On the other hand, MQL outperforms LN2 cooling for tool wear, surface roughness/topography and cutting force, LN2 cooling is better than MQL in temperature reducing.Öğe Performance of Multilayer Coated and Cryo-Treated Uncoated Tools in Machining of AISI H13 Tool Steel-Part 1: Tungsten Carbide End Mills(Springer, 2021) Cicek, Adem; Kivak, Turgay; Ekici, Ergun; Kara, Fuat; Ucak, NecatiThis paper focused on the performance of tungsten carbide end mills in machining of AISI H13 hot work tool steel under dry and wet conditions. The tool performance was evaluated in terms of resultant cutting force (Fc), average surface roughness (Ra) and tool life. In the milling tests, four categories of end mills were used: untreated (U), cryo-treated (CT), cryo-treated and tempered uncoated (CTT) and TiAlN/TiN multilayer coated (MLC). The tests were performed at four cutting speeds (80, 100, 120, 140 m/min), three feeds (0.08, 0.12, 0.16 mm/rev) and a depth of cut (2 mm). The test results showed that the lowest values of Fc and Ra were obtained with the use of MLC end mills. However, the cryogenic treatment was also effective on decreasing Fc and Ra. In addition, while the CTT end mills provided a slight improvement in tool life under dry conditions, they showed a remarkable improvement of 126.1% in comparison with the untreated ones under wet conditions. Although the CTT end mills exhibited a superior performance to U and CT ones, the MLC end mills were much more resistant to abrasive wear. This study is organized into two parts (WC-Co and HSS) to observe the effects of deep cryogenic treatment on performance of two different tool materials and to compare cryo-treated end mills with multilayer coated ones. This part is related to the cryogenic treatment of tungsten carbide end mills, whereas part two is regarding cryo-treated HSS end mills.Öğe Performance of Multilayer Coated and Cryo-treated Uncoated Tools in Machining of AISI H13 Tool Steel-Part 2: HSS End Mills(Springer, 2021) Cicek, Adem; Ekici, Ergun; Kivak, Turgay; Kara, Fuat; Ucak, NecatiThis part of the study aimed to investigate the effects of cryogenic treatment applied to uncoated high speed steel (HSS) end mills on cutting forces (Fc), surface roughness (Ra), and tool life. The milling tests were performed at four cutting speeds (40, 50, 60, and 70 m/min), three feeds (0.018, 0.024, and 0.03 mm/rev), and a depth of cut (2 mm) under dry and wet conditions. Three categories of uncoated HSS end mills were used in the tests: conventional heat treated (CHT), cryo-treated (CT), cryo-treated and tempered uncoated (CTT), and TiAlN/TiN multilayer coated (MLC) end mills. The test results showed that the lowest values of Fc and Ra were measured with the use of MLC end mills. However, the cryogenic treatment provided in a reduction in Fc and Ra values. In addition, under wet conditions, the CTT end mills exhibited better performance than the CHT ones by 71.4%. The test results showed while cryogenic treatment is a useful and cheap application in steels, it does not have the ability to compete with coating technology in terms of tool life in milling of hot work tool steel. This paper is organized into two sections. In the first section, cutting performance of cryo-treated and multilayer coated end mills is evaluated. In the second section, performance comparison of cryo-treated WC-Co (Part 1), HSS (Part 2), and MLC end mills in milling of AISI H13 hot work tool steel is presented.Öğe Study on turning performance of PVD TiN coated Al2O3+TiCN ceramic tool under cutting fluid reinforced by nano-sized solid particles(Elsevier Sci Ltd, 2020) Kivak, Turgay; Sarikaya, Murat; Yildirim, Cagri Vakkas; Sirin, SenolDue to their excellent chemical stability, hardness and abrasion resistance, ceramic cutting tools are suitable for operations at very high cutting speeds, which play a decisive role in high productivity. Thanks to these properties, they are significantly resistant to high temperatures occurred in the cutting zone. However, after a certain point, excessive temperature rise in the cutting zone brings some problems. This is seen as a problem that should be overcome as it affects negatively machining efficiency. However, the poor resistance of ceramic tools to thermal shocks is an important factor restricting the use of flood cooling. Alternatively, promising results have been achieved recently in MQL and nanofluid-MQL applications particularly on carbide cutting tools. When these methods are used together with ceramic cutting tools, the behavior of ceramic cutters and their effect on machinability outputs is still a matter of curiosity. Therefore, in order to observe the interaction between ceramic cutting tool and minimum quantity lubrication (MQL) and nanofluid-MQL, we investigated the turning performance of PVD TiN coated Al2O3+TiCN ceramic tool under dry, pure-MQL and nanofluid-MQL reinforced by nano-sized solid particles such as graphene nanoplatelets (GNPs) and multi walled carbon nanotubes (MWCNTs). Experiments were carried out to investigate the effect of cooling/lubrication (C/L) environment and cutting parameters on tool life, surface roughness and maximum temperature of chip. In addition, a series of experiments were also made to observe the effect of only C/L environment on the wear behavior of the ceramic tools and the machined surface topography while keeping the cutting parameters constant. As a result, pure-MQL contributed to the reduction of nose wear by about 69% compared to dry machining, while GNPs based nanofluid-MQL helped to reduce the surface roughness by 19.42%.
