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Yazar: Baday, Şehmus × Dil: en ×

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  • Küçük Resim
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    Milling Inconel 718 workpiece with cryogenically treated and untreated cutting tools
    (SpringerLink, 2021-07-17) Gürbüz, Hüseyin; Baday, Şehmus
    Although Inconel 718 is an important material for modern aircraft and aerospace, it is a kind material, which is known to have low machinability. Especially, while these types of materials are machined, high cutting temperatures, BUE on cutting tool, high cutting forces, and work hardening occur. Therefore, in recent years, instead of producing new cutting tools that can withstand these difficult conditions, cryogenic process, which is a heat treatment method to increase the wear resistance and hardness of the cutting tool, has been applied. In this experimental study, feed force, surface roughness, vibration, cutting tool wear, hardness, and abrasive wear values that occurred as a result of milling of Inconel 718 material by means of cryogenically treated and untreated cutting tools were investigated. Three different cutting speeds (35-45-55 m/min) and three different feed rates (0.02- 0.03-0.04 mm/tooth) at constant depth of cut (0.2 mm) were used as cutting parameters in the experiments. As a result of the experiments, lower feed forces, surface roughness, vibration, and cutting tool wear were obtained with cryogenically treated cutting tools. As the feed rate and cutting speed were increased, it was seen that surface roughness, vibration, and feed force values increased. At the end of the experiments, it was established that there was a significant relation between vibration and surface roughness. However, there appeared an inverse proportion between abrasive wear and hardness values. While BUE did not occur during cryogenically treated cutting tools, it was observed that BUE occurred in cutting tools which were not cryogenically treated. Also, in this study, the statistical validity of the experimental values was tested with the help of secondorder equations and analyses of variance (ANOVA). R2 values obtained as 99.14%, 99.76%, and 97.98% for vibration, surface roughness, and feed force values were modeled statistically with the help of second-order equations, respectively.
  • Küçük Resim
    Öğe
    Analysis of spheroidized AISI 1050 steel in terms of cutting forces and surface quality
    (Slovenska Akademia Vied, 2016) Baday, Şehmus; Başak, Hüdayim; Güral, Ahmet
    In this study, the effects of microstructure differences obtained with the application of different spheroidizing heat treatment cycles on medium carbon steel on cutting forces and surface roughness values were investigated. For this purpose, a group of AISI 1050 materials was annealed at 700°C below Ac1 temperature for 720 min and cementite phases were spheroidized by the traditional method. Another group of materials was quenched after austenitization at 850°C for 15 min and then cementites were spheroidized in the ferrite matrix by over-tempering separately at 600°C for 15 and 60 min and at 700°C for 60 min. Machining of the samples was tested under dry cutting conditions in CNC turning center with SNMG 120408 cementite carbide cutting tool and proper PSBNR 2525M12 tool holder with 75-degree edge angle. Cutting forces of traditionally spheroidized samples were lower than the samples spheroidized after quenching. In addition, their cutting forces decreased due to the increase in the average sizes of spheroidal cementite. Minimum surface roughness value was obtained from the samples which were spheroidized at 600°C for 15 min after quenching. However, surface roughness rate of the sample increased as spheroidizing time increased.
  • Küçük Resim
    Öğe
    Modelling of effects of various chip breaker forms on surface roughness in turning operations by utilizing artificial neural networks
    (Gazi Üniversitesi, 2016-03-01) Gürbüz, Hüseyin; Baday, Şehmus; Sözen, Adnan
    In this study, the effects of different chip breaker forms and cutting parameters on the surface roughness on machined surfaces were investigated experimentally in turning of AISI 1050 steel; and values of surface roughness obtained from experiments were determined with empirical equations using artificial neural networks. The utilizing of ANN was offered to determine the surface roughness depending on chip breaker forms and cutting parameters of AISI 1050 steel. The back propagation learning algorithm and fermi transfer function were used in artificial neural network. Experimental measurements data were employed as training and test data in order to train the neural network created. The best fitting training data set was attained with ten neurons in two hidden layers 6 of which were at first hidden layer and 4 of which were at second hidden layer, making it possible to predict surface roughness with precision at least as good as that of the experimental error over the entire experimental range. After network training, R2 value was found as 0.978, and average error as 0.018%. When the results of mathematical modelling are examined, the computed surface roughness is observed to be apparently within acceptable values
  • Küçük Resim
    Öğe
    Effect of MQL flow rate on machinability of AISI 4140 steel
    (Taylor & Francis, 2020-06-27) Gürbüz, Hüseyin; Gönülaçar, Yunus Emre; Baday, Şehmus
    Many studies were performed about the influence of minimum quantity lubrication (MQL) technique on cutting performance in the literature, but there is no paper examining the effect of different MQL flow rates and cutting parameters on machinability of AISI 4140 material as a whole. In this study, the effects of different MQL flow rates and cutting parameters on surface roughness, main cutting force and cutting tool flank wear (VB), with great importance among the machinability criteria, and forming as a result of the machining of AISI 4140, were revealed. At the end of the experiments, it was determined that rise of flow rate affected main cutting forces positively to a certain extent; yet, it exhibited no significant effect on surface roughness, but reduced VB. Also, it was observed that both main cutting force and surface roughness increased with the increase of feed, while generally decreased with the increase of cutting speed. It was seen that flank wear was positively affected by the increase in flow rate; and this decreased with the increase in flow rate. R2 values obtained as 99.8% and 99.9% for main cutting forces and surface roughness values modeled statistically with the help of quadratic equations, respectively.
  • Küçük Resim Yok
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  • Küçük Resim
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    Optimization of welding parameters of AISI 431 and AISI 1020 joints joined by friction welding using taguchi method
    (Bilecik Şeyh Edebali Üniversitesi, 2022-06-30) Adin, Mehmet Şükrü; İşcan, Bahattin; Baday, Şehmus
    Martensitic stainless steel AISI 431 and low carbon steel AISI 1020 are materials used together in many different industries. However, important problems are encountered when welding (fusion welding) these materials to each other. For this reason, friction welding process (Solid-state welding) is used to join these dissimilar metals. There are very few studies on joining these materials with friction welding. Therefore, the optimization of the welding parameters used in joining these dissimilar steel pairs with friction welding is of great important. In addition, the effects of the factors dependent on friction welding parameters need to be well understood. In this study, AISI 431 and AISI 1020 steel bars were successfully joined by friction welding, and the effects of welding parameters on tensile strength and axial shortening were investigated, and welding parameters were optimized using Taguchi method to obtain quality weld joints. The experimental results of the study showed that the highest tensile strength (573.32 MPa) of the joints was 54.53%, higher than the lowest tensile strength (370.99 MPa), the highest axial shortening (23.18 mm) was 650.16%, higher than the lowest axial shortening (3.09 mm). The optimal parameters for average axial shortening and average tensile strength were determined as A3B1C3 and A3B3C2; and the highest percentage contribution values for axial shortening and tensile strength were found to be 51.55% (rotating speed) and 63.90% (rotating speed); and R2 values for the average axial shortening and average tensile strengths were found to be 97% and 99.3%, respectively.