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 mechanical properties of fe-doped intermetallic nial

Son yıllarda NiAl gibi intermetalik malzemeler, yüksek sıcaklık uygulamalarında iyi mekanik ve fiziksel özellikler göstermektedir. Özellikle yüksek erime noktası, iyi oksidasyon direnci ve yüksek sertlik bu intermetaliklerin en dikkat çeken özellikleri arasındadır. NiAl intermetalikler, Fe katkılı malzemenin yanında Ti, Cr, Co ve Mo gibi malzemelerin katkısıyla çeşitli uygulamalarda kullanım alanına sahiptir. Özellikle Fe katkılı intermetalikler, yoğunluk, yüksek dayanım ve iyi korozyon direnci gibi özellikler sergilemektedir. Bu çalışmada NiAl toz karışımı ile Fe tozu farklı sinterleme sıcaklığında sinterlenmiştir. Sinterlenen numunelere sırasıyla SEM ve EDX analizleri gerçekleştirilmiştir

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

Production of ni3al-fe composite and investigation of mechanical properties

In intermetallics high resistance to creep and oxidation, high strenght, low density are desired properties. Sintering process was used in this study by adding different amounts of Fe powder to Ni-Al powder mixture. When the properties of the sample after sintering were examined 40% weight Fe added composition was found as the most suitable ratio in terms of mechanical properties. Analyses were conducted metallographically on the samples after sintering, the densities were calculated, hardness and shear strengths were determined. According to the data 40% Fe added composition had 5,82 gr/cm3 of density, 92,8 HB hardness values and displayed 221 MPa shear strength

Production of Co-Cr-Ti composite and investigation of mechanical properties

Intermetallic materials such as Co2Ti, Cr2Ti are among advanced technology materials that have outstanding mechanical and physical properties for high temperature applications. Especially creep resistance, low density and high hardness properties stand out in such intermetallics. The microstructure, mechanical properties of %64Co– %32Cr and %4Ti powders were investigated using specimens produced by tube furnace sintering at 800–1200 C temperature. A composite consisting of ternary additions, a metallic phase, Ti, Cr and Co have been prepared under Ar shroud and then sintered in tube furnace. XRD, scanning electron microscope, were used to characterize the properties of the specimens. Experimental results carried out for composition %64Co–%32Cr–%4Ti at 1200 C suggest that the best properties as 182.09 HV and 5,584 g/cm3 density were obtained at 1200 C

Production of ni3al-cr composite and investigation of mechanical properties

Nickel aluminide intermetallic compounds possess attractive properties that make them good candidates for high temperature structural applications. It is known that Ni3Al intermetallics are commonly used in various application fields with the addition of Cr, in particular as well as elements such as Ti, Co, Mo and Fe which are related to this group for improving properties thereof. Given this information, sintering process was used in this study by adding different amounts of Cr powder to Ni3Al powder mixture. When the properties of the sample after sintering were examined we were able to reveal the effects of Cr on Ni3Al and consider 3% Cr added compositions as the most suitable ratio in terms of mechanical properties. Analyses were conducted metallographically on the samples after sintering, the densities were calculated, hardness and shear strengths were determined. According to the data 3% Cr adde

Çocuklarda Görme Muayenesi Açısından Ailelerin Farkındalığının Değerlendirilmesi

Amaç: Sağlıklı çocuk izleminde objektif görme muayenesinin yapılması önemlidir. Bu çalışmada ebeveynlerin çocuklarında yapılan görme muaye nesi farkındalığının, tutum ve davranışlarının değerlendirilmesi amaçlan mıştır. Gereç ve Yöntem: Bu araştırma tanımlayıcı, kesitsel bir anket çalışmasıdır, Veriler 6 yaşından küçük çocukların ebeveyleri tarafından doldurulan 183 anketten elde edilmiştir. Bulgular: Değerlendirilen çocukların %53.6 (n=98)’sı kızdı ve %51.4 (n=94)’ünde hiç görme muayenesi/değerlendirmesinin yapılmadığı belir tilmekteydi. Ailelerin %44.3 (n=81)’ünde görme sorunu vardı. Çalışmaya katılan çocukların %82 (n=150)’sinde ekran maruziyeti olduğu, günlük maruziyet süresinin medyanının 2 saat ve maruziyete başlama yaşının medyanının 12 ay olduğu görüldü. Onsekiz ay altındaki çocuklarda ekran maruziyeti oranının %44,2 olduğu görüldü ve maruziyet süresinin medyanı 1 saat idi. Daha önce bir göz hekimi tarafından muayene edilmemiş çocuk ların ebeveynlerinin %87.1’i çocuklara düzenli göz muayenesi yapılmasının gerekli olduğunu ve %89.7’si ise okula başlamadan önce çocuklarına bir göz muayenesi yaptırmayı düşünmekteydi. Sonuç: Aile sağlığı merkezleri tarafından yapılan görme taramaları hakkın da ebeveynlerin bilgilendirilmesi, gerekli ise göz hekimine yönlendirilme leri ve özellikle erken dönemde başlayan ekran maruziyetinin çocukların göz sağlığını olumsuz etkilediğinin anlatılması ebeveynlerin görme sağlığı hakkındaki duyarlılıklarını arttıracaktır

Obesity and Anesthesia Management

The prevalence of obesity is rapidly increasing throughout the world. Correspondingly, anesthetic procedures in obese patients are also increasing due to both treatment of obesity and other surgical problems of obese patients. Anesthesia-related complications are also seen in obese patients than in normal-weighted population. The importance of anesthetic applications in obese patients originates from physiological and pharmacokinetic alterations. Inhalation of these patients via mask or intubation during general anesthesia may be difficult or even impossible. Determination of extubation time after awakening from anesthesia is also a critical decision. Sleep apnea syndrome and postoperative atelectasis are more common in obese patients than in normal-weighted population. Another vital complication that should be emphasized is thromboembolism, whose incidence and severity may be decreased by pharmacological and functional preventive modalities. This patient population has elevated risk of perioperative mortality and morbidity. Prior to any elective surgical procedure, an obese patient should be thoroughly evaluated to check medical conditions that may increase perioperative mortality risk. Since anesthesiologists will gradually encounter more obese patients, they need a better comprehending of the difficulties of obesity during anesthetic procedures and taking more preventive measures for their patients to avoid complications, or rendering them less traumatic, if any