Investigation of adhesion and tribological behavior of borided aısı 310 stainless steel

In the present study, the effects of the boriding process on adhesion and tribological properties of AISI 310 steel were investigated. Boriding was performed in a solid medium consisting of Ekabor-II powders at 1123 and 1323K for 2 and 6 h. The boride layer was characterized by optical microscopy, the X-ray diffraction technique and the micro-Vickers hardness tester. The X-ray diffraction analysis of the boride layers on the surface of the steels revealed the existence of FexBy, CrxBy and NixBy compounds. Depending on the chemical composition of substrates, the boride layer thickness on the surface of the AISI 310 steel was found to be 56.74 μm. The hardness of the boride compounds formed on the surface of the AISI 310 steel ranged from 1658 to 2284 HV0,1, whereas the Vickers hardness value of the untreated steel AISI 310 was 276 HV0,1. The wear tests were carried out in a ball-disc arrangement under a dry friction condition at room temperature with an applied load of 10N and with a sliding speed of 0.3 m/s, at a sliding distance of 1000m. The wear surfaces of the steel were analyzed using an SEM microscopy and X-ray energy dispersive spectroscopy EDS. It was observed that the wear rate of unborided and borided AISI 310 steel ranged from 4.57 to 71.42 mm3/Nm

Investigation of wear behavior of borided dın x15crnisi25 steel

In the present study, effect of the boriding process on adhesion and tribological properties of DIN X15CrNiSi25 steel has been investigated. Boriding was performed in a solid medium consisting of Ekabor- II powders at 1123 and 1323K for 2 and 6 h. The boride layer was characterized by optical microscopy, Xray diffraction technique and the micro-Vickers hardness tester. . X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FexBy, CrxBy and NixBy compounds. Depending on the chemical composition of substrates, the boride layer thickness on the surface of the X15CrNiSi25 steel was found to be 56.74 μm. The hardness of the boride compounds formed on the surface of the X15CrNiSi25 steel ranged from 1658 to 2284 HV0,1, whereas Vickers hardness values of the untreated steel X15CrNiSi25 were 276 HV0,1. The wear tests were carried out in a ball-disc arrangement under a dry friction condition at room temperature with an applied load of 10N and with a sliding speed of 0.3 m/sec at a sliding distance of 1000m. The wear surfaces of the steel were analyzed using a SEM microscopy and X-ray energy dispersive spectroscopy EDS. It was observed that the wear rate of unborided and borided X15CrNiSi25 steel ranged from 4.57 to 71.42 mm3/Nm

Investigation of diffusion kinetics of borided x6cr17 steel

In this study, the case properties and diffusion kinetics of DIN X6Cr17 steel borided in Ekabor-II powder were investigated by conducting a series of experiments at temperatures of 1123, 1223 and 1323K for 2, 4 and 6 h. The boride layer was characterized by optical microscopy, X-ray diffraction technique and micro-Vickers hardness tester. X-ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FexBy, CrxBy and NixBy compounds. The thickness of boride layer increases by increasing boriding time and temperature for all steels. Depending on the chemical composition of substrates, the boride layer thickness on the surface of the X6Cr17 steel was found to be 50.48 μm and 91.62 μm, respectively. The hardness of the boride compounds formed on the surface of the X6Cr17 steel ranged from 1658 to 2284 HV0,1

Investigation of surface properties of boriding Co-Mg alloy containing 3.0% Mg

Bu çalışmada, %97 Co ve %3 Mg içeren Co-Mg alaşımına borlama işlemi gerçekleştirilmiştir. Co-Mg alaşım malzemesini üretmek için toz metalurjisi (TM) yöntemi kullanılmıştır. Bu yöntemde, Co ve Mg metal tozları kapalı kaplar içerisinde homojen bir şekilde karıştırılarak şekillendirilmeleri için özel olarak tasarlanmış silindirik kalıplara dökülmüştür. Tek eksenli preste 300 bar basınç altında preslendikten sonra Argon gazı atmosferi ortamında 530 °C sıcaklıkta sinterlenmiştir. Sinterlenerek üretilen numunelere sırasıyla sertlik, yoğunluk ve yüzey pürüzlülüğü testleri uygulanmıştır. Sertlik testi sonrası 123 HV0,05 değeri elde edilirken ölçülen yoğunluk değeri ise 4,95 gr/cm3 olarak bulunmuştur. Bu işlemler sonrasında numuneler kapalı fırın ortamında 850 ve 900 °C sıcaklık ve 1.5-4.5 saat değişen sürelerde borlama işlemi gerçekleştirilmiştir. Bu işlem sonrasında SEM ve XRD analiz çalışmaları yapılmıştır. Analiz sonrasında borür tabakaları 850 °C sıcaklıkta 1,5 saat sürede 55 µm olarak bulunurken en yüksek 900 °C sıcaklık 4,5 saat sürede 140 µm olarak ölçülmüştür. Borlanmış Kobalt-Magnezyum alaşımlarına uygulanan XRD analizi sonucunda CoB, Co2B ve Co fazları elde edilmiştir. Mg elementinin hızlı bozulma özelliğinden dolayı yapılarda kısmende olsa boşluklar oluşmuştur.In this study, Co-Mg alloying containing 97% Co and 3% Mg was performed. Powder metallurgy (TM) method was used to produce Co-Mg alloy material. In this method, the Co and Mg metal powders are poured into cylindrical molds, which are specially designed to be shaped by mixing homogeneously in closed containers. It was pressed under 300 bar pressure in uniaxial press and sintered at 530 ° C in atmosphere of Argon gas atmosphere. Sintered samples were subjected to hardness, density and surface roughness tests respectively. After the hardness test, it was found that the value of HV0,05 was 123 and the measured density value was 4.95 gr/cm3 . After these processes, samples were subjected to boring in 850 and 900 °C temperature and 1.5-4.5 hours in closed oven environment. After this process, SEM and XRD analyzes were conducted. After the analysis, the boride layers were measured as 55 µm in 850 °C for 1.5 hours and the highest 900 °C temperature was measured as 140 µm in 4.5 hours. As a result of XRD analysis applied to boriding CobaltMagnesium alloys CoB, Co2B and Co phases were obtained. Due to the rapid deterioration of the Mg element, some gaps were formed in the structures.Afyon Kocatepe Üniversitesi BAPK 17.MYO.05 no'lu proj

%10 CO içeren CR-CO alaşımının borlama özelliklerinin incelenmesi

Bu çalışmada, %90 Cr ve %10 Co içeren Cr-Co alaşımının borlama işlemi gerçekleştirilmiştir. Toz metalurjisi yöntemiyle Cr ve Co metal tozları 24 saat süreyle homojen bir şekilde karıştırılarak dairesel şekle sahip olması için silindirik kalıplara dökülmüş ve 300 bar basınç altında preslendikten sonra Argon gazı atmosferine sahip tüp fırın içerisinde 1000 °C sıcaklıkta ısıl işleme tabi tutulmuştur. Bu işlem sonucunda üretilen alaşım malzemelere sertlik ve yoğunluk testleri uygulanmıştır. Sinterleme sonucunda malzemelerde 125 HV0,05 değeri elde edilirken yoğunluk değeri 4,76 gr/cm3 olarak ölçülmüştür. Elde edilen numunelere özel kapalı kutular içerisinde üzerlerine ticari Ekabor II tozu dökülerek fırın ortamında 850 ve 900 °C sıcaklıklarda 1.5 – 4.5 saat değişen sürelerde borlama işlemi gerçekleştirilmiştir. Borlanan numunelere metalografik analiz olarak XRD analiz çalışması yapılmıştır. Bu Analiz sonucunda CrB, Cr2B ve Cr2Co fazları elde edilmiştir. Mikrosertlik ölçümü sonucunda en yüksek değer 900 °C sıcaklık 4.5 saat süre sonrasında yapılan borlamada 375 HV0,05 olarak ölçülmüştür.In this study, boronization of Cr-Co alloy containing 90% Cr and 10% Co was performed. Cr and Co metal powders were poured into cylindrical molds and pressed under 300 bar pressure and then heat treated at 1000 °C in an oven with Argon gas atmosphere. As a result of this process, hardness and density tests were applied to the alloy materials produced. As a result of sintering, 125 HV0.05 values were obtained in the materials while the density value was measured as 4.76 gr/cm3. Commercial Ekabor II powder was poured in special closed boxes on the obtained samples and boronizing process was carried out in the oven environment at 850 and 900 °C temperatures for 1.5-4.5 hours. Boronized samples were analyzed by XRD analysis as metallographic analysis. CrB, Cr2B and Cr2Co phases were obtained as a result of this analysis. As a result of microhardness measurement, the highest value was measured as 375 HV0,05 in boriding after 900 °C temperature and 4.5 hours

Borlanmış nikel-magnezyum alaşımının yüzey özelliklerinin incelenmesi

Bu çalışmada % 93 Ni ile % 7 Mg toz karışımından TM yöntemiyle üretilmiş ve farklı sıcaklıklarda borlanmış Nikel-Magnezyum alaşımının yüzey özellikleri incelenmiştir. Numuneler 530 °C sıcaklıkta sinterlenmişlerdir. Numuneler Ø20x5 mm boyutlarında kesilerek gerekli zımparalama (1000 G) işlemlerinden geçirilmiş ve 1 μm’luk Alümina solüsyon kullanılarak parlatılmıştır. Borlama işlemi katı ortamda, ticari Ekabor II bor tozu kullanılarak elektrik rezistanslı bir fırın içesinde 900 ve 1000 ºC’de 1,5 ve 4,5 saat süresince gerçekleştirilmiştir. Borlanan numuneler kesitten kesilerek gerekli zımparalama ve parlatma işlemlerinden sonra elde edilen borür tabaka kalınlıkları Nikon MA100 marka optic mikroskop yardımıyla ölçülmüştür. Borlama işlemi sonucunda elde edilen borür fazları Shimadzu XRD 6000 marka XRD cihazı kullanılarak elde edilmiştir. Borlanmış Nikel-Magnezyum numunelerinin XRD analizi sonucunda Ni3B, Ni2B, NiB ve Mg fazları elde edilmiştir. Borlama sıcaklığı ve süresine bağlı olarak Nikel- Magnezyum numuneler üzerinde değişen kalınlıklarda borür tabakaları elde edilmiştir. Borlanma işlemi sonucunda numunelerin yüzey pürüzlülük değerlerinde artışlar tespit edilmiştir. Borlanmış ve borlanmamış Nikel-Magnezyum numunelerin yüzey pürüzlülük değerlerinin 0.2 ile 0.56 arasında değiştiği tespit edilmiştir.In this study, a mixture of 93% Ni and 7% Mg powder was produced by the TM method and surface properties of boronized Nickel-Magnesium alloy at different temperatures and times were investigated. The samples were sintered at 530°C. The Nickel-Magnesium specimens were cut into Ø20x5 mm dimensions, ground up to 1000G and polished using 1 μm Al2O3 solution. The boriding heat treatment was carried out in a solid medium containing an Ekabor-II powder mixture placed in an electrical resistance furnace operated at the temperature of 900 and 1000 ºC for 1.5 and 4.5 h under atmospheric pressure. The microstructures of polished and etched cross-sections of the specimens were observed under a Nikon MA100 optical microscope. The presence of borides formed in the coating layer was confirmed by means of X-ray diffraction equipment (Shimadzu XRD 6000) using Cu Kα radiation. X-ray diffraction analysis of boride layers on the surface of the tungsten revealed the existence of Ni3B, Ni2B, NiB and Mg compounds. Boron layers were obtained at varying thicknesses on Nickel-Magnesium samples depending on the boron temperature and duration. As a result of the boring process, increases in the surface roughness values of the samples were determined. It has been found that the surface roughness values of boronized and non-boronized nickel-magnesium samples change from 0.2 to 0.56

Waste Biomass Based Energy Supply Chain Network Design

Reducing dependence on fossil fuels, alleviating environmental impacts and ensuring sustainable economic growth are among the most promising aspects of utilizing renewable energy resources. Biomass is a major renewable energy resource that has the potential for creating sustainable energy systems that are critical in terms of social welfare. Utilization of biomass for bioenergy production is an efficient alternative for meeting rising energy demands, reducing greenhouse gas emissions and thus alleviating climate change. A supply chain for such an energy source is crucial for assisting deliverance of a competitive end product to end-user markets. Considering the existing constraints, a mixed integer linear programming (MILP) model for waste biomass based supply chain was proposed in this study for economic performance optimization. Performance of the proposed modelling approach was demonstrated with a real life application study realized in İstanbul. Moreover, sensitivity analyses were conducted which would serve as a foresight for efficient management of the supply chain as a whol

Farklı kompozisyonlardaki fe-mg alaşımların mekanik özelliklerinin incelenmesi

Toz metalurjisi, çok küçük boyutlu partikülleri birbirine bağlayarak karışık şekilli parçaların üretimini sağlayan bir yöntemdir. Bu çalışmada, Fe-Mg toz karışımları homojen bir şekilde toz karıştırıcıda 24 saat süreyle karıştırılmıştır. Elde edilen tozlar tek eksenli preste 300 bar basınç altında soğuk olarak preslendikten sonra Ar atmosfer ortamında 620 °C sıcaklıkta sinterleme işlemine tabi tutulmuşlardır. Sinterlenerek üretilen numunelere sırasıyla sertlik, yoğunluk ve gözeneklilik testleri uygulanmıştır. Metalografik analiz olarak XRD çalışması yapılmıştır. XRD analiz sonucu olarak Fe, Mg ve MgO faz değerleri bulunmuştur.Powder metallurgy is a method of producing mixed shaped parts by connecting very small sized particles together. In this work, Fe-Mg powder mixtures were homogeneously mixed in the powder mixer for 24 hours. The powders obtained were cold pressed under a uniaxial prestressing pressure of 300 bar and then subjected to sintering at 620 °C in Ar atmosphere. Hardness, density and porosity tests were applied to the samples produced by sintering, respectively. XRD work was done as a metallographic analysis. As a result of XRD analysis, Fe, Mg and MgO phase values were found

CNN-based Gender Prediction in Uncontrolled Environments

With the increasing amount of data produced and collected, the use of artificial intelligence technologies has become inevitable. By using deep learning techniques from these technologies, high performance can be achieved in tasks such as classification and face analysis in the fields of image processing and computer vision. In this study, Convolutional Neural Networks (CNN), one of the deep learning algorithms, was used. The model created with this algorithm was trained with facial images and gender prediction was made. As a result of the experiments, 93.71% success rate was achieved on the VGGFace2 data set and 85.52% success rate on the Adience data set. The aim of the study is to classify low-resolution images with high accuracy

Sustainability assessment of biomass-based energy supply chain using multi-objective optimization model

In recent years, population growth and lifestyle changes have led to an increase in energy consumption worldwide. Providing energy from fossil fuels has negative consequences, such as energy supply constraints and overall greenhouse gas emissions. As the world continues to evolve, reducing dependence on fossil fuels and finding alternative energy sources becomes increasingly urgent. Renewable energy sources are the best way for all countries to reduce reliance on fossil fuels while reducing pollution. Biomass as a renewable energy source is an alternative energy source that can meet energy needs and contribute to global warming and climate change reduction. Among the many renewable energy options, biomass energy has found a wide range of application areas due to its resource diversity and easy availability from various sources all year round. The supply assurance of such energy sources is based on a sustainable and effective supply chain. Simultaneous improvement of the biomass-based supply chain's economic, environmental and social performance is a key factor for optimum network design. This study has suggested a multi-objective goal programming (MOGP) model to optimize a multi-stage biomass-based sustainable renewable energy supply chain network design. The proposed MOGP model represents decisions regarding the optimal number, locations, size of processing facilities and warehouses, and amounts of biomass and final products transported between the locations. The proposed model has been applied to a real-world case study in Istanbul. In addition, sensitivity analysis has been conducted to analyze the effects of biomass availability, processing capacity, storage capacity, electricity generation capacity, and the weight of the goals on the solutions. To realize sensitivity analysis related to the importance of goals, for the first time in the literature, this study employed a spherical fuzzy set-based analytic hierarchy method to determine the weights of goals