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Aging Effect on Microstructure and Machinability of Corrax Steel
(Eos Assoc, 2020) Guldibi, Ahmet Serdar; Demir, Halil
In this paper, the influence of the aging process on the microstructure and machinability of Corrax Steel was investigated for four samples: a solution heat-treated (A0) and three samples aged at 400 degrees C (A4), 525 degrees C (A5.25) and 600 degrees C (A6) for four hours. The effect of aging temperature on hardness was examined. Machining tests were carried out using a CNC lathe with a multi-layer coated PVD (AlTiN) cutting tool, at various cutting speeds (50, 100, 150, 200, 250, 300, 350m/min) with constant feed rate (0.1mm/rev) and 1mm constant cutting depth. The microstructure was investigated using an optical microscope and EDS attached SEM. The effect of aging on reverted austenite formation was also evaluated. In order to understand the changes in surface topology, cutting forces and vibrations were measured. With increasing aging temperature, the lath martensite was transformed to plate martensite because of the formation of precipitates and reverted austenite. Aging at different temperatures increased hardness up to 58%, cutting forces up to 117% and surface roughness up to 450%. The results describe the effect of the aging treatment on cutting forces, surface topology, tool wear and vibrations.
Aisi 304 paslanmaz sac malzemenin lazerle işlenmesinde kesme parametrelerinin yüzey pürüzlülüğü, kerf genişliği ve çapak yüksekliğine etkisinin araştırılması
(2022) Cebeci, İbrahim; Özlü, Barış; Demir, Halil
Yapılan çalışmada, AISI 304 paslanmaz sac malzemenin lazer kesim işleminde kesme parametrelerinin yüzey pürüzlülüğü, kerf genişliği ve çapak yüksekliği üzerine etkileri araştırılmıştır. Lazer kesme işleminde iki farklı gaz basıncı (0.8 bar ve 1 bar), dört farklı kesme hızı (20 mm/sn, 24 mm/sn, 28 mm/sn ve 32 mm/sn) ve dört farklı frekans (3500 Hz, 4000 Hz, 4500 Hz ve 5000 Hz) değerleri kullanılmıştır. Yüzey pürüzlülüğü ölçümleri, değişken kesme parametreleriyle kesilmiş sac malzeme üzerinde yapılmıştır. Dijital mikroskop kullanılarak numunelerin kerf genişlikleri ve çapak yükseklikleri ölçülmüştür. Sonuç olarak, kesme hızının artması ile yüzey pürüzlülüğü, kerf genişliği ve çapak yüksekliğinin azalmasına neden olmuştur. Frekans değerinin artırılması yüzey pürüzlülük ve çapak yüksekliğinin azalmasına ve kerf genişliğinin artmasına neden olmuştur. Frekans değerinin değiştirilmesinin çapak yüksekliği üzerine önemli bir etkisinin olmadığı görülmüştür.
Aisi h13 ve aisi d2 çeliklerinin delinmesi esnasinda kesme bölgesinde oluşan sicakliğa kesici takim kaplamasinin ve işleme parametrelerinin etkisi
(2015) Tekaüt, İsmail; Demir, Halil
Delik delme işleminde, takım ve işlem performansı için sıcaklık önemli bir faktördür. Bu nedenle kesme bölgesinde oluşan sıcaklığın analiz edilmesi işlem performansının tahmin edilebilmesi açısından önemlidir. Bu amaçla, sanayide sıkça kullanılan AISI H13 ve AISI D2 malzemeleri 14 mm çapında kaplamasız ve (AlCrN monolayer) kaplamalı karbür matkaplarla dik işleme merkezinde delinmiştir. Kesme bölgesinde oluşan sıcaklıklar matkapların soğutma kanallarına yerleştirilen ısıl çiftler yardımıyla ölçülmüştür. Deneylerde dört farklı kesme hızı (60, 75, 90 ve 108 m/dak) ve üç farklı ilerleme miktarı (0.15, 0.20 ve 0.25 mm/dev) kullanılmıştır. Deneysel çalışma sonucu, ilerleme miktarı ve kesme hızı artışı sıcaklığın azalmasına yol açmıştır. Kaplamalı matkapların kaplama özelliğinden dolayı ısı iletim katsayısının düşük olması, kaplamalı matkaplarla yapılan işlemlerde sıcaklığın daha fazla olmasına neden olmuştur. Bütün deneylerde, AISI H13 malzemesinin işlenmesi esnasında oluşan sıcaklık değerleri AISI D2 malzemesinin işlenmesi esnasında oluşan sıcaklık değerlerinden daha fazla çıkmıştır. Bu duruma malzemelerin yapısal ve kimyasal farklılıklarının neden olduğu düşünülmektedir.
Analysis and optimization of process parameters affecting on the tensile strength of pla and iron-reinforced pla samples fabricated by fused deposition modeling method
(2023) Kuruoglu, Yasin; Akgün, Mahir; Demir, Halil
This study focuses on investigating the influence of printing parameters on the tensile strength of PLA and iron-reinforced PLA samples produced using FDM technology. Filament material (PLA and iron-reinforced PLA), infill ratio (20, 40 and 60%), layer thickness (0.1, 0.2 ve 0.3 mm), printing speed (40, 60 and 80 mm/s) and raster angle (30, 45 and 60°) were selected as process parameters. The experimental design was based on the Taguchi L18 index. Signal-to-Noise (S/N) ratio, variance analysis (Anova) and regression analyses were used to statistically analyze the tensile strength values obtained as a result of experimental measurements. The outcomes of this study show that the reinforcement to PLA material decreases the tensile strength and increases the % elongation. The maximum tensile strength was measured as 33.55 MPa at 60% infill rate, 0.3 mm layer thickness, 60 mm/s printing speed and 60° raster angle in PLA filament material, which is the optimum process parameters.
Cutting parameter optimization in shoulder milling of commercially pure molybdenum
(Springer Heidelberg, 2018) Gokce, Huseyin; Ciftci, Ibrahim; Demir, Halil
Due to its superior properties such as high melting point (2617 degrees C), high thermal conductivity and low thermal expansion at higher temperatures, molybdenum is a refractory metal and is used for making critical parts in defense, space, electronics and nuclear industries. High cost of molybdenum makes the selection of suitable cutting conditions imperative in machining operations in order to obtain the required surface quality and dimensional accuracy. In this study, suitable cutting tools and cutting parameters were aimed to be determined in terms of cutting forces (F-c) and average surface roughness (R-a) when shoulder milling commercially pure molybdenum. The milling tests were carried out at 0.05, 0.1, 0.15, 0.2 mm/tooth feed rates and 75, 100, 125, 150 m/min cutting speeds using four different cutting tools. The Taguchi's experimental design (L16 orthogonal array) technique was implemented. Analysis of variance was used to determine the effects of cutting tools and cutting parameters on R-a and F-c. The results showed that the feed rate is the most influential parameter for F-c while the cutting speed is for R-a.
The Effect of Mechanical Properties and the Cutting Parameters on Machinability of AISI 5140 Steel Cooled at High Cooling Rates After Hot Forging
(Gazi Univ, 2019) Ozlu, Baris; Demir, Halil; Turkmen, Mustafa
In this study, the effect of mechanical properties and cutting parameters (Cp) on the machinability of AISI 5140 steel cooled at high cooling rates after hot forging was investigated. The microstructural examinations and hardness measurements of the as-received AISI 5140 steel and the workpieces cooled in the oil and polymerized water after hot forging were performed. Turning process was conducted by using a coated ceramic tool at five different cutting speeds (Vc) (120, 150, 180, 210, and 240 m/min), four different feed rates (fn) (0.04, 0.08, 0.12, and 0.16 mm/rev), and four different depths of cut (ap) (0.4, 0.6, 0.8, and 1 mm) under dry machining conditions. SEM examinations of the cutting tools were also performed. It was seen from the results that the changing microstructure and hardness values had a significant effect on cutting forces (Fc) and surface roughness (Ra) from the Cp depending on cooling rate. While the highest Fc were reached in the workpiece with the highest hardness cooled in the polymerized water after hot forging, the lowest surface roughness (Ra) was obtained in the same workpiece.
The effect of mechanical properties and the cutting parameters on machinability of aisi 5140 steel cooled at high cooling rates after hot forging
(2019) Özlü, Barış; Demir, Halil; Türkmen, Mustafa
In this study, the effect of mechanical properties and cutting parameters (Cp) on the machinability of AISI 5140 steel cooled at high cooling rates after hot forging was investigated. The microstructural examinations and hardness measurements of the as-received AISI 5140 steel and the workpieces cooled in the oil and polymerized water after hot forging were performed. Turning process was conducted by using a coated ceramic tool at five different cutting speeds (Vc) (120, 150, 180, 210, and 240 m/min), four different feed rates (fn) (0.04, 0.08, 0.12, and 0.16 mm/rev), and four different depths of cut (ap) (0.4, 0.6, 0.8, and 1 mm) under dry machining conditions. SEM examinations of the cutting tools were also performed. It was seen from the results that the changing microstructure and hardness values had a significant effect on cutting forces (Fc) and surface roughness (Ra) from the Cp depending on cooling rate. While the highest Fc were reached in the workpiece with the highest hardness cooled in the polymerized water after hot forging, the lowest surface roughness (Ra) was obtained in the same workpiece.
The effects of aging on machinability of 6061 aluminium alloy
(Elsevier Sci Ltd, 2009) Demir, Halil; Guenduez, Sueleyman
In this study, the effect of artificial aging on the machinability of 6061 Al-alloy was investigated for the as-received, solution heat treated (SHT) and solution heat treated and then aged (SHTA) conditions. The experimental work has revealed that different aging times at 180 degrees C and the cutting speed significantly affected the machined surface roughness values. However, cutting forces were not influenced significantly by aging and cutting speed except for SHT workpieces having the lowest hardness. (C) 2008 Elsevier Ltd. All rights reserved.
THE EFFECTS OF CUTTING TOOL COATING AND MACHINING PARAMETERS IN DRILLING OF STEEL AISI H13 AND AISI D2
(Gazi Univ, Fac Engineering Architecture, 2015) Tekaut, Ismail; Demir, Halil
In drilling, temperature is an important factor for the tool and the machining performance. For this reason, analysis of the temperature in the cutting zone is essential for predicting the machining performance. In this study, commonly used AISI H13 and AISI D2 steels were drilled using uncoated and (AlCrN monolayer) coated carbide drills of 14 mm diameter on a vertical machining centre. The cutting zone temperatures were determined using the thermocouples inserted into the coolant holes of the drills. The tests were carried out at four different cutting speeds (60, 75, 90 and 108 m/min) and three different feed rates (0.15, 0.20 and 0.25 mm/rev). The experimental results showed that increasing feed rate and cutting speed led to decrease in the temperature. The lower heat conduction of the coated drills resulted in the higher temperature. In all the tests, drilling of AISI H13 caused higher temperature than that of AISI D2. It is considered that this was caused by the structural and chemical differences of the materials.
Evaluation of the effect of hot forging and cooling conditions on the microstructure, hardness and machinability of medium carbon DIN 41Cr4 steel
(Gazi Univ, Fac Engineering Architecture, 2023) Ozlu, Baris; Akgun, Mahir; Demir, Halil
This work DIN 41Cr4 tempered steel of hot forging applied focuses on the investigation of machinability of samples obtained by cooling in sand and air. The machinability evaluation has made in terms of main cutting force (Fc) and surface roughness (Ra). DIN 41Cr4 original material (OM), sand (SC) and air cooling (AC) samples has investigate microstructure and hardness changes. Turning experiments carried out at five different cutting speeds, four different feed rates and depth of cut. As a result, it has seen that the cooling environment of the samples after hot forging has a significant effect on the hardness and microstructure. The lowest main Fc was 131.54 N in the OM, while the highest Fc was 337.49 N in the AC sample in the turning of the samples. Evaluated in terms of Ra, the lowest Ra was obtained as 0.505 mu m in the AC sample, while the highest Ra was obtained as OM 1.793 mu m. It has been observed that the main Fc increases, while the Ra somewhat decreases depending on the increase in hardness and decrease in grain size. In general, SEM examinations, it has been seen that built-up edge (BUE) and breaks occurred in the cutting tools.
EXPERIMENTAL ANALYSIS AND THEORETICAL MODELLING OF CUTTING PARAMETERS IN THE DRILLING OF AISI H13 STEEL WITH COATED AND UNCOATED DRILLS
(Univ Zagreb Fac Mechanical Engineering & Naval Architecture, 2018) Tekaut, Ismail; Demir, Halil; Seker, Ulvi
In this study, drillability experiments were carried out on the AISI H13 hot work steel which is difficult to machine. Uncoated and AlCrN-coated carbide drills, empty set14 mm, were used at 4 cutting speeds (60, 75, 90 and 108 m/min) and three different feed rates (0.15, 0.20 and 0.25 mm/rev). As a result of the experimental work, it was observed that an increase in the feed rate caused an increased on the thrust force in the workpiece machined with both the uncoated and coated drills. While an increase in the cutting speed caused the thrust force to increase in operations performed with uncoated drills, the increased cutting speed led to a decreased torque. In contrast, an increase in the cutting speed caused both the thrust force and the torque to decrease in the operations with coated drills. Stresses occurring on the drills were analyzed and a mathematical model was developed using the finite element method and the ANSYS Workbench package software.
Fdm yöntemiyle üretilen abs, pla ve petg numunelerin yüzey pürüzlülüğü ve çekme dayaniminin modellenmesi ve optimizasyonu
(2022) Kuruoglu, Yasin; Akgün, Mahir; Demir, Halil
Bu çalışma, Eriyik Yığma Modelleme (FDM) teknolojisi kullanılarak üretilen numunelerin yüzey kalitesi ve çekme dayanımı üzerinde ABS, PLA ve PETG filamentlerin ve baskı parametrelerinin etkisini incelemektedir. Bu amaçla, Taguchi L27 dizinine göre baskı deney tasarımı yapılmıştır. Filament malzemesi, dolum oranı, katman kalınlığı, doldurma hızı ve tarama açısı baskı parametreleri iken, yüzey pürüzlülüğü ve çekme mukavemeti de baskı kalitesi göstergeleridir. Ayrıca, deneysel ölçümler sonucu elde edilen yüzey pürüzlülüğü ve çekme dayanımı değerlerini matematiksel olarak modellemek için regresyon analizi de uygulanmıştır. Bu çalışmanın sonuçları filament malzemesinin yüzey pürüzlülüğü ve çekme dayanımı üzerinde önemli bir rol oynadığını göstermektedir. ABS ve PETG filamentlere göre PLA filament de yüzey pürüzlülüğünün sırasıyla ortalama %7,23ve %54,19 oranında daha az olduğu ve ayrıca, diğer filamentlere göre PLA filament de çekme dayanımın sırasıyla ortalama %46,46 ve %34,12 oranında daha yüksek olduğu tespit edilmiştir.
Hardox 450 çeliğinin lazerle delinmesinde kesme parametrelerinin delik kalitesi üzerine etkisinin incelenmesi ve kesme parametrelerinin optimizasyonu
(2021) Çirakoglu, Fulya; Özlü, Barış; Demir, Halil
Bu çalışmada, Hardox 450 çeliğinin lazerle delme işleminde kesme parametrelerinin (odak noktası, kesme hızı, gaz basıncı ve lazer gücü) yüzey pürüzlülüğü ile üst ve alt delik dairesellik toleransı üzerine etkisi incelenmiştir. Lazer kesme işlemi için deney tasarımı, Taguchi $L_{18}$ ortogonal dizinine göre yapılmıştır. Deneylerde kesme parametreleri olarak; iki farklı odak noktası, üç farklı gaz basıncı, üç farklı kesme hızı ve üç farklı lazer gücü seçilmiştir. Taguchi yöntemine göre lazer delme işleminde kullanılan kesme parametreleri optimize edildi. Ayrıca kesme parametrelerinin yüzey pürüzlülüğü ile üst ve alt delik dairesellik toleransı üzerine etkilerinin belirlenmesi için varyans (ANOVA) analizi yapılmıştır. Sonuç olarak; Hardox 450 çeliğinin delinmesinde kesme hızının ve lazer gücünün artması yüzey pürüzlülüğünün azalmasına neden olurken gaz basıncının ve odak noktasının artması yüzey pürüzlülüğünün artmasına neden olmuştur. Gaz basıncı, kesme hızı ve lazer gücünün artması ile üst ve alt delik dairesellik toleransı artarken, odak noktasının azalması üst ve alt delik dairesellik toleransının azalmasına neden olmuştur. En düşük yüzey pürüzlülüğü 0,718 ?m için optimum kesme parametreleri -1 mm odak noktası, 0,7 bar gaz basıncı, 1500 mm/sn kesme hızı ve 2600 W lazer gücü olarak belirlenmiştir. Üst ve alt delik için sırası ile en küçük boyutsal tamlık 20,069 mm ve 20,024 mm için optimum kesme parametreleri -1 mm odak noktası, 0,7 bar gaz basıncı, 1100 mm/sn kesme hızı ve 2200 W lazer gücü olmuştur. Varyans analizi sonucu yüzey pürüzlülüğü ile üst ve alt delik dairesellik toleransı için sırası ile en etkin parametre %77,17 %51,40 ve %71,80 ile gaz basıncı olmuştur.
Hardox 500 çeliğinin lazerle işlenmesinde kesme geometrisine ve işleme parametrelerine bağlı kesim kalitesinin değerlendirilmesi
(2022) Eksılmez, Nihal; Özlü, Barış; Demir, Halil
Lazer kesme işleminde yüzey pürüzlülüğünün (Ra), üst kerf genişliğinin (ÜKG) ve alt kerf genişliğinin (AKG) kalitesi farklı kesme geometrilerinde uygun kesme parametrelerinin seçimine bağlıdır. Lazer kesme işlemi yapan firmaların minimum RA, ÜKG ve AKG en önemli talepleri arasındadır. Bu çalışmada, lazerle Hardox 500 çeliği farklı geometrilerde ve kesme parametrelerinde kesilerek kesim geometrilerinin ve kesme parametrelerinin kesim kalitesine etkisi araştırılmıştır. Deneylerde üç farklı kesme geometrisi (Düz, V ve yay) kullanılmıştır. Her geometri farklı kesme parametrelerinin kombinasyonunda kesilmiştir. Sonuç olarak; Hardox 500 çeliğinin, lazerle düz geometride kesilmesinde odak noktasının (ON) iş parçasına yaklaşması, gaz basıncının (GB) ve kesme hızının (KH) artırılması ile Ra’nın en düşük değerine (2,099 ?m) ulaşılmıştır. En yüksek Ra değeri yay geometrisinde ON’nın iş parçasından uzaklaşması, GB’nın en düşük değerinde ve KH’nın maksimum değerinde 4,795 ?m ölçülmüştür. Üç kesme geometrisi için -0,5 mm ON’da, 850 mm/sn KH’da ve 0,7 bar GB’da ÜKG’nin ve AKG’nin minimum değerlerine ulaşılmıştır.
Hızlı prototipleme teknolojisi harç yığma yöntemi ile üretilen modellerin ölçüsel sapmalarının ve yüzey pürüzlülüğünün incelenmesi
(2020) Özlü, Barış; Pısık, Okan; Demir, Halil
Bu çalışmada, farklı geometrik toleranslarda ve ölçülerde model tasarımı yapılmıştır. Tasarlanan model, hızlıprototip üretim uygulamalarından harç yığma tekniği kullanılarak üretilmiştir. Model üretimi sırasında farklı uçtipi (katman kalınlığı) ve inşa yöntemleri kullanılmıştır. Modellerin üretiminde ABS M30 malzemesikullanılmıştır. Üretilen her bir parça üç boyutlu tarama cihazı ile taranarak tasarlanan modellerin geometrikhataları ve ölçüsel sapmaları değerlendirilmiştir. Ayrıca farklı uç tipi ve inşa yöntemlerine göre üretilenmodellerin yüzey pürüzlülük değerleri ölçülmüştür. Üretilen ve tasarımı yapılan modellerin geometrik hatalarıve ölçüsel sapmalar karşılaştırıldığında ölçü tamlığı, en ince uç tipi olan T10 ve Solid Normal (SN) inşa yöntemiile üretilen modelde ölçülmüştür. Bununla birlikte T10 uç tipi ve Solid Normal (SN) inşa yöntemi ile üretilenmodelde optimum yüzey pürüzlülüğü 4 µm olarak ölçülmüştür.
Influence of the heat treatment on the microstructure and machinability of AISI H13 hot work tool steel
(Springer London Ltd, 2018) Demir, Halil; Gunduz, Suleyman; Erden, Mehmet Akif
In this work, the influence of heat treatment on the microstructure and machinability of AISI H13 tool steel was investigated for the as-received (AR), water-quenched (Q), quenched and single-tempered (QST) and quenched and double-tempered (QDT) conditions. The machining tests were carried out through turning method at various cutting speeds. The results indicated that heat treatment conditions and the cutting speed affected the surface roughness of samples. However, cutting forces were not affected by steel microstructure and cutting speed except to those of water-quenched samples.
An Investigation into the Influences of Grain Size and Grinding Parameters on Surface Roughness and Grinding Forces when Grinding
(Assoc Mechanical Engineers Technicians Slovenia, 2010) Demir, Halil; Gullu, Abdulkadir; Ciftci, Ibrahim; Seker, Ulvi
This study was carried out to investigate the effects of grain size on workpiece surface roughness and grinding forces when surface grinding AISI 1050 steel. A previously designed and constructed dynamometer was used to measure and record the forces developed during grinding. Grinding tests were carried out using different grinding wheels of different grains. Ground still ace roughness measurements were also carried out. The results showed that grain size significantly affected the grinding forces and surface roughness values. Increasing grain size and depth of cut increased the grinding forces and surface roughness values. For different grain sizes, depth of cuts of 0.01 and 0.02 mm did not result in any significant variations in the grinding forces but further increase in depth of cut led to variations of up to 50% in grinding forces. (C) 2010 Journal of Mechanical Engineering. All rights reserved.
AN INVESTIGATION INTO THE INFLUENCES OF GRINDING WHEEL HARDNESS AND GRINDING PARAMETERS ON SURFACE ROUGHNESS AND GRINDING FORCES
(Gazi Univ, Fac Engineering Architecture, 2008) Demir, Halil; Gullu, Abdulkadir
This study was carried out in order to examine the influences of grinding wheel hardness on surface roughness and grinding forces during surface grinding. Grinding tests were carried out using Al(2)O(3) grinding wheels with I, M and Q hardness grades at different table speeds and at different depth of cuts. AISI 1050 (50 HRc) and AISI 4140 steels (52 HRc) were used as the workpiece materials. In order to measure the grinding forces generated during grinding, the dynamometer previously designed and manufactured was used. This dynamometer was also connected to a personal computer to save the grinding force data. The roughness of surfaces were also measured. It is seen significant increases on surface roughness by increasing wheel hardness and grinding forces. The grinding operations carried out using grade I grinding wheels produced higher surface roughness and mean grinding force values by 53.5% and 59.8%, respectively, than those obtained by grade Q grinding wheel.
AN INVESTIGATION INTO THE INFLUENCES OF GRINDING WHEEL STRUCTURE ON SURFACE ROUGHNESS AND GRINDING FORCES
(Gazi Univ, Fac Engineering Architecture, 2008) Demir, Halil; Gullu, Abdulkadir
This study was carried out in order to examine the influences of grinding wheel structure on surface roughness and grinding forces during surface grinding. Grinding tests were carried out using Al(2)O(3) grinding wheels at different table speeds and at different depth of cuts. The structures of the grinding wheels were 3, 5 and 7. AISI 1050 steel (50 HRc) was used as the workpiece material. For measurement of the grinding forces developed during grinding, a previously designed and constructed dynamometer was used. This dynamometer was also connected to a personal computer to save the grinding force data. The ground surface roughness values were also measured. Increasing grinding wheel structure resulted in significant increases in surface roughness values. However, its influence on grinding forces was marginal. The highest cutting force was obtained when grinding using grinding wheel having the lowest structure at the highest depth of cut.
INVESTIGATION OF MACHINABILITY OF COOLED MICROALLOY STELL IN OIL AFTER THE HOT FORGING WITH COATED AND UNCOATED CBN CUTTING TOOLS
(Yildiz Technical Univ, 2018) Ozlu, Barn; Demir, Halil; Turkmen, Mustafa; Gunduz, Suleyman
The aim of this study was to investigate the cutting forces and surface roughness of 38MnVS6 microalloyed steel quenched in oil following hot forging. The machinability tests were carried out by turning under dry cutting conditions using coated and uncoated cubic boron nitride (CBN) cutting tools at five different cutting speeds (120, 150, 180, 210 and 240 m / min), a constant feed rate (0.04 mm / rev) and a constant chip depth (0.6 mm). The microalloyed steel used in the experimental study was optically examined and a hardness test was applied. Scanning electron microscopy (SEM) was used to evaluate the wear on the cutting tools. The findings for the 38MnVS6 steel which was oil quenched after forging showed that due to the high cooling rate, a martensite structure had been formed and the hardness value was high. The lowest surface roughness values of 0.367 mu m and 0.164 mu m were obtained at a cutting speed of 180 m / min with the coated and the uncoated CBN cutting tools, respectively. In the turning experiments, the surface roughness values measured using the coated CBN cutting tool were about 103% higher than those measured using the uncoated CBN cutting tool and the highest cutting forces were obtained at a cutting speed of 120 m / min.

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