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3b metal yazıcı kullanılarak mig-mag kaynak yöntemi ile tamironarım kaynak uygulamasına bir örnek
(2018) Ayan, Yusuf; Sarı, Ertan; Kahraman, Nizamettin
Bu çalışmada; MIG-MAG kaynak ünitesi, 3B metal yazıcıya monte edilerek MAG kaynak yöntemi ile bir tamironarım kaynak işlemi gerçekleştirilmiştir. Bu amaç için kırılmış kabul edilen bir makine dişlisi kullanılmıştır.Kırılmış dişlinin tasarımı bilgisayar destekli ortamda tasarlanıp lazer kesme işlemi ile üretilmiştir. Daha sonra kırıkolan dişli parçaları hassas bir şekilde 3B metal yazıcının tablasına sabitlenmiştir. 3B yazıcıyla metal malzeme veplastik malzeme biriktirme işlemleri arasında önemli bir fark bulunmaktadır. 3B yazıcılarda plastik malzemekullanıldığında çalışma sıcaklığı yaklaşık 190-200 °C arasında iken metal malzeme ergitilirken çalışma sıcaklığıyaklaşık 3000-4000 °C’ye ulaşır. Bu çalışma sıcaklığının çok yüksek olması 3 boyutlu metal yazıcının çalışmasınıolumsuz yönde etkilemektedir. Bu nedenle çalışmada metal doldurma işlemini gerçekleştirmek için 3 boyutlumetal yazıcıda önemli uyarlamalar yapılmıştır. Kırık dişli parçalarının tamir edilecek bölgesini doldurma işlemiMAG kaynağı ile ilk ikisi parçanın üst tarafından diğer ikisi ise alt tarafından olacak şekilde dört pasodagerçekleştirilmiştir.
Aisi 409 ve ç1010 çeliğin östenitik elektrod kullanarak mig kaynak yöntemi ile birleştirilmesi ve mekanik özelliklerinin araştırılması
(2009) Kılınçer, Sabri; Kahraman, Nizamettin
Bu çalışmada, gaz metal ark kaynak yöntemi ile farklı metallerin kaynaklanabilirliği araştırılmıştır. Bu amaçla, ferritik paslanmaz çelik (AISI 409) ile düşük karbonlu çelik (Ç1010) malzemeler östenitik bir ilave metal kullanılarak otomatik robot yardımıyla değişik parametrelerde birleştirilmişlerdir. Kaynaklı numunelerin mekanik ve mikroyapı özelliklerini belirlemek için, çekme, eğme, sertlik ve çentik darbe testi ile mikroyapı çalışmaları yapılmıştır. Yapılan çekme testi sonucunda ayrılma, kaynak bölgesi dışarısında ve düşük karbonlu çelik levha ortasında meydana gelmiştir. Eğme testi sonucunda kaynak bölgesinde gözle görülebilir bir çatlak ve yırtılma hatasına rastlanmamıştır. Bütün kaynak parametrelerinde, kaynak metali sertliğinin ITAB ve esas metalden yüksek olduğu görülmüştür. Mikroyapı çalışmaları sonucunda kaynak metali ve ısının tesiri altında kalan bölgede (ITAB) tane irileşmesinin meydana geldiği tespit edilmiştir.
Al - si alaşımının tig kaynağında darbeli akımın mikroyapı, sertlik, eğme ve çekme dayanımına etkisi
(2008) Durgutlu, Ahmet; Kahraman, Nizamettin; Gülenç, Behçet
Bu çalışmada, AA 4000 serisi Al-Si alaşımı levhalar TIG kaynak yöntemi ile alternatif ve darbeli akım kullanılarak birleştirilmişlerdir. Kullanılan akım türünün kaynaklı birleştirmenin özelliklerine olan etkilerini görmek amacı ile birleştirilen numunelere mikroyapı, çekme, sertlik ve eğme testleri uygulanmıştır. Deneyler sonucunda, darbeli akımın düşük ısı girdisine, kaynak metalinde tane incelmesine ve alternatif akıma göre kaynak metali sertliğinde artışa neden olduğu belirlenmiştir. Birleştirmelere uygulanan çekme testlerinde, darbeli akım ile birleştirilen numunelerin alternatif akıma nazaran daha yüksek çekme dayanımı gösterdikleri tespit edilmiştir. Yapılan eğme testi sonucunda numunelerde yırtılma ve çatlak oluşumu gibi bir yüzey hatasına rastlanılmamıştır.
Analysis of mechanical and microstructural properties of gas metal arc welded dissimilar aluminum alloys (AA5754/AA6013)
(Elsevier Science Sa, 2021) Yuruk, Ali; Cevik, Bekir; Kahraman, Nizamettin
The use of aluminum alloys to reduce weight in air, sea, and land vehicles is increasing rapidly, especially due to their low density, excellent corrosion resistance, good forming properties, and increasable mechanical properties. A common aspect of all the relevant industrial sectors is the need to join the many parts of manufactured technological products using welding methods. In these industries, using welding to join different aluminum alloys having high mechanical properties is especially important. However, despite the widespread usage areas, it is very difficult to join different aluminums and their alloys via welding. In this study, AA5754/AA6013 aluminum alloys were joined using automatic gas metal arc welding (GMAW). Welded joints were created at two different welding speeds (150 and 180 mm/min) and three different welding current values (130, 140, and 150 A). This study investigated the microstructural and mechanical properties of AA5754/AA6013 aluminum alloy sheets joined at different welding speeds and current values. The macro and microstructures of samples taken from the welded joints were examined. In addition, hardness, tensile, bending, and fatigue tests were performed on the welded samples. The findings obtained as a result of the tests were evaluated and interpreted in light of the literature.
ANN prediction of impact toughness of ship steel/stainless steel plates produced by explosive welding
(Academic Publication Council, 2020) Kaya, Yakup; Kalyon, Ali; Kahraman, Nizamettin
In this study, ship steel/stainless steel plates were produced by joining ship steel with stainless steel using explosive welding process. The characterization of the joining interface of the plates was carried out by optical microscopic examination. Charpy impact tests were conducted at different temperatures to determine the impact toughness of the ship steel/stainless steel plates and the effect of the rolling on the impact toughness. In addition, after the Charpy impact test, the fractured surfaces of the specimens were investigated via scanning electron microscopy (SEM). Using the data obtained as a result of the impact toughness tests, an artificial neural network (ANN) model was unproved for the prediction of the impact toughness. Five different material types, two different rolling directions, and eight different temperatures were used as the input parameters of the Charpy impact tests. The impact toughness values obtained at the end of the tests were used as the output parameters of the generated prediction model. The high R-2 value obtained in the developed prediction model demonstrated that it could be successfully used for predicting impact toughness.
Carbon dioxide (CO2) laser machine design, production and test studies for marking and cutting processes
(Gazi Univ, 2024) Kole, Alper; Ayan, Yusuf; Kahraman, Nizamettin
Since its early development, lasers had big impact in today's technology advancement by facilitating our daily life. The manufacturing industry has taken the largest share of laser technology, and it has become a preferred technology in many manufacturing applications. Almost all material types can be processed with the laser and laser technology is widely used in industry for marking, engraving, and cutting processes. This article discusses designing and manufacturing of a low-budget CO2 laser machine, for marking, engraving, and cutting applications. All major components of the machine including resonator, optical train, cutting head and control systems have been discussed in detail for interested readers to implement a similar system. The resonator on the machine was designed and manufactured to allow repeated gas filling which is a major benefit for economical and extended service life as compared to similar commercially available systems. The machine has been described from initial material list and manufacturing process involved, all the way to the final aforementioned application examples for rubber, wood, and plastic materials. The laser machine system is currently installed in Karabuk Univesity's manufacturing engineering department and used for undergraduate teaching and learning. Furthermore, it is sufficient capacity for use in medium-sized operations in advertising, hobby, forest products, textile, leather, and small-scale engineering works.
Characterization of the weld zone of Grade AH36 steel ship plate joined at the real marine conditions through underwater welding
(Gazi Univ, Fac Engineering Architecture, 2020) Colak, Zahit; Ayan, Yusuf; Kahraman, Nizamettin
In this study, Grade AH36 steel ship plate was joined at both the atmospheric and real underwater conditions at ascending different depths through shielded metal arc welding process. The isolated E6013 rutile electrode was used in welding process. The welded specimens firstly subjected to visual inspection and this was followed by radiographic test. Bending and impact toughness tests were also carried out in order to determine the mechanical properties of the welded joints. Microstructural examines were performed to observe the structural transformation and hardness test was also conducted on the weld zones. Non-destructive test results showed that the specimens joined underwater had weld defect such as slag remains on the weld surface and between the pass, gas porosities, grooves and the lack of penetration. According to the bending test results, when the difference of water depth increased, the tests resulted in adversely at some angles due to defects like remains, gas porosities etc. on the weld metal. With respect to impact toughness tests, the specimens welded at atmospheric conditions presented better toughness than the others. The maximum hardness value was measured from the weld metal and this was followed by the heat affected zone (HAZ) and base metal sequentially. Microstructure evolutions showed that structures of the weld metals were dendritic, rolled structure of the base metal in the HAZ was destroyed and partial grains growth was seen in this section.
Characterization of the Welding Zone of Automotive Sheets of Different Thickness (DP600 and DP800) Joined by Resistance Spot Welding
(Springer India, 2022) Aydin, Kemal; Hidiroglu, Mehtap; Kahraman, Nizamettin
Automotive industry in recent years, has gained great importance. In line with this, DP600 and DP800 dual-phase steels and the electrical resistance spot welding method were used in the study. During the experimental trials, different welding currents (6, 7, and 8 kA) were selected and all other welding parameters were kept constant. The effects of the welding parameters on microstructure, hardness, tensile-shear, and cross-tensile strength were analyzed. In the phase measurements, 27.06-29.97% martensite and 70.73-73.85% ferrite phases were found. When the hardness values in the HAZ regions were examined, it was seen that the highest hardness values were 356 +/- 5 HV in the DP600 and 451 +/- 5 HV in the DP800 with a current intensity of 6 kA. Consequently, it was determined that tensile-shear and cross-tensile strengths had increased in parallel with the increase in the welding current and the highest values were determined as 8 kA-15.91 kN in tensile shear and 8 kA-4.91 kN in cross-tensile strength.
Coating of AISI 8620 steel by plasma spraying and characterization of coating
(Gazi Univ, Fac Engineering Architecture, 2018) Kaya, Yakup; Akturkoglu, Faruk; Kahraman, Nizamettin
The worn surfaces of AISI 8620 material were prepared before coating and then they were coated by coating plasma spraying method using various powders of different chemical compositions. By doing so, they were made ready for use. Initially, surface roughness values of the coated test specimens were determined. Under service conditions, wear test was done to define the coatings' wear resistance, hardness test was done for the characterisation of coating layer and their interfaces. Tensile test was also carried out to define the adhesion strength of the interface. Also, SEM/EDS tests were done to define their interface properties. The highest hardness was measured for 72F-NS coating. The results revealed that CRC-106 coating led to highest wear resistance and this is followed by 68 F-NS-1, 72F-NS and AMDRY 962 coatings. Finally, the result of SEM/EDS examinations showed the formation of oxides within the coating layer and coating interface.
Corrosion and mechanical-micro structural aspects of dissimilar joints of Ti-6Al-4V and Al plates
(Pergamon-Elsevier Science Ltd, 2007) Kahraman, Nizamettin; Gulenc, Behcet; Findik, Fehim
In this study, Ti-6Al-4V and Al plates were joined by explosive welding at various explosive loads. Tensile-shear, bending, hardness, microstructure and corrosion behaviours of the explosively joined samples were investigated. At the end of the tensile-shear tests carried out according to ASTM D 3165-95 standard, no seperation was observed in the interfaces of the joined samples. The results of the bending tests also showed no sign of any distinctive seperation, crack and tear in the interfaces. The highest hardness values were measured in regions next to interfaces. The optical microscope and SEM examinations revealed that an increment in wavelength and amplitude was observed with increasing explosive load. It is seen from the corrosion test results that materials loss was high at the beginning of the corossion tests but the rate of material loss decreased later on. Furthermore, increasing deformation with increasing explosive load increased the materials loss in corrosion tests. (c) 2006 Elsevier Ltd. All rights reserved.
Development of a New High Strength Alloy from Low Alloy Steel Wire by Innovative Additional Cold Wire Feeding Used in Wire Arc Additive Manufacturing
(Mary Ann Liebert, Inc, 2024) Saribiyik, Ziya; Ayan, Yusuf; Kahraman, Nizamettin
One of the most important features of the wire arc additive manufacturing (WAAM) is the ability to produce new structures from different materials. Thanks to the ease of application of the WAAM, more than one same or different material can be involved in the production process. Thus, WAAM has the potential to produce new material structures from raw wire metals with different chemical contents. In this study, it was aimed to produce a new alloy structure using WAAM. A novel cold wire feeding technique with an external system and gas metal arc welding (GMAW) process was implemented for the fabricating of a new alloy part. In the fabrication process, two different grades and ratios of ER70S-6 (90%) and 316LSi (10%) steel wires were used and melted simultaneously. The new alloy structure was successfully fabricated, and significant changes were found in the microstructure and tensile strength because of Cr and Ni elements transferred from the secondary wire (316LSi). In the microstructure of the new alloy, structures such as acicular ferrite, martensite, and bainite were observed. As a result of the different fabrication approach applied, a significant increase in tensile strength was found. The tensile strength of the new alloy structure exceeded 1000 MPa and almost 100% increase in strength was observed compared to single-material structures. In addition, the ductility of the produced structure was found to be sufficient. The study showed that new alloys with improved mechanical properties can be produced with the cold wire feeding + GMAW approach.
Diffusion bonding of commercially pure titanium to low carbon steel using a silver interlayer
(Elsevier Science Inc, 2008) Atasoy, Euren; Kahraman, Nizamettin
Titanium and low carbon steel plates were joined through diffusion bonding using a silver interlayer at various temperatures for various diffusion times. In order to determine the strength of the resulting joints, tensile-shear tests and hardness tests were applied. Additionally, optical, scanning electron microscopy examinations and energy dispersive spectrometry elemental analyses were carried out to determine the interface proper-ties of the joint. The work showed that the highest interface strength was obtained for the specimens joined at 850 degrees C for 90 min. It was seen from the hardness results that the highest hardness value was obtained for the interlayer material and the hardness values on the both sides of the interlayer decreased gradually as the distance from the joint increased. in energy dispersive spectrometry analyses, it was seen that the amount of silver in the interlayer decreased markedly depending on the temperature rise. In addition, increasing diffusion time also caused some slight decrease in the amount of silver. (C) 2008 Elsevier Inc. All rights reserved.
The effect of AC and MFDC resistance spot welding technology on mechanical properties of new generation automotive steels
(Pamukkale Univ, 2021) Hidiroglu, Mehtap; Kahraman, Unal; Kahraman, Nizamettin
Usage of UHSS (ultra high-strength steels) had increased in recent years, automobile Body in White-BIW- manufacturers had faced the challenge of choosing between two types of currents for resistance spot welding equipment The objective of this work is to compare the effects ofwelds obtained from both AC and MFDC (alternate current-AC- power source and medium frequency constant current one-MFDC) machines on mechanical performance. Two different welding equipment had been used for making joints between as-delivered 22MnB5 and DP600 steel sheets. The micro-hardness results, tensile shear (TS) and cross tension (CT) tests of resistance spot welded (RSW) joints between as - delivered (22MnB5) and double phase (DP600) steels for both AC and MFDC process are detailed. According to the results, comparatively lower hardness values were observed in the weld metal and heat effected zones of the welded samples obtained by MFDC technology compared to AC technology. The positive effect was observed in the strength and elongation values of the samples welded with MFDC technology according to AC technology. When the CT and TS test results were evaluated, more than 5% improvement is observed on welded samples with MFDC technology. The originality of this paper presents a comparative study of joint performance properties effect for both AC and MFDC process on dissimilar joints between as-delivered 22MnB5 and DP600.
The Effect of Pulsed Current on Microstructure, Hardness, Bending and Tensile Strength in TIG Welding of Al - Si Alloys
(Gazi Univ, 2008) Durgutlu, Ahmet; Kahraman, Nizamettin; Gulenc, Behcet
In this study, AA 4000 series Al-Si alloys sheets were joined by TIG welding method using alternative and pulsed current. Tensile test, bending test, hardness test and microstructure examination of joined test specimens were carried out in order to see the effect of current type on mechanical properties of welded samples. Experimental results showed that, pulsed current leads to low heat input, grain refinement and hardness increase in weld metal compared to alternative current were used. Specimens joined by the pulsed current showed higher tensile strength than the specimens welded by the alternative current. After bending test, cracks, tearing and surface defection were not observed on the samples.
The Effect of Welding Parameters on Weld Nugget Formation in Titanium Sheets at Resistance Spot Welding
(Gazi Univ, 2011) Kaya, Yakup; Kahraman, Nizamettin
In this study, commercial pure titanium sheets (ASTM Grade 2) were joined by resistance spot welding method by using different parameters (electrode force, welding current and welding time). In the welded joints; effects on weld nugget diameter, electrode dept intensity, crack type, hardness and microstructure properties of electrode force, welding current and welding time were investigated. The experimental results showed that increasing electrode force, welding current and welding time increased the weld nugget diameter and electrode dept intensity. On examination of fracture types, welding parameters were understood to be suitable for this study. It was seen that weld nugget hardness is higher than HAZ and base metal in all weld parameters. Microstructural examinations showed that the grains formed increasing welding parameters were growed and local twins were formed due to heat emerged during welding and high plastic deformation.
The effects of electrode force, welding current and welding time on the resistance spot weldability of pure titanium
(Springer London Ltd, 2012) Kaya, Yakup; Kahraman, Nizamettin
In this study, commercially pure titanium sheets (American Society for Testing and Materials grade 2) were welded by resistance spot welding at various welding parameters. The welded joints were subjected to tensile-shearing tests in order to determine the strength values. In addition, the hardness and microstructural examinations were carried out in order to examine the influence of welding parameters on the welded joints. The experimental results showed that increasing electrode force, welding current and welding time increased the tensile-shearing strength of the welded specimens. Hardness measurement results indicated that welding nugget had the highest hardness and this was followed by the heat-affected zone and the base metal. Microstructural examinations showed the growth of the weld nugget grains with increasing heat input. Besides, due to plastic deformation during the welding process, twins were formed and at the same time twins increased with increasing electrode force, welding current and welding time.
Enhancing weld strength in high-strength steels: the role of regional preheating in RSW
(Walter De Gruyter Gmbh, 2024) Aydin, Kemal; Hidiroglu, Mehtap; Kahraman, Nizamettin
In this study, automotive in sector use STRENX 700 CR and DP 800 steels were joined by resistance spot welding using medium frequency direct current. Some parts were joined under atmospheric conditions, while others were joined by applying regional preheating to their heat-affected zones before welding. The design, manufacturing, and adaptation of the preheating system to the welding machine were carried out as part of this study, considering it as a new system. After the joining process, nondestructive and destructive tests were performed on resistance spot welding connections between STRENX 700 CR and DP 800 steels. Hardness tests revealed that the preheating applied to the heat-affected zones before welding reduced the hardness of the weld metal by approximately 8 %, while the microstructure analysis showed that the regional preheating increased both the weld metal and the heat-affected zones width. The tensile-shear strength increased by about 7 %, and the cross-tension test strength increased by about 5 % with the preheating applied to the heat-affected zones before welding. In both the tensile-shear and cross-tension tests, all failures occurred in the form of button shearing from the heat-affected zones. The regional preheating treated specimens showed the highest fatigue life, with an average of 947,632 cycles.
Experimental study of diffusion welding/bonding of titanium to copper
(Elsevier Sci Ltd, 2012) Aydin, Kemal; Kaya, Yakup; Kahraman, Nizamettin
In the present study, Ti-6Al-4V alloy was bonded to electrolytic copper at various temperatures of 875, 890 and 900 degrees C and times of 15, 30 and 60 min through diffusion bonding. 3 MPa uniaxial load was applied during the diffusion bonding. Interface quality of the joints was assessed by microhardness and shear testing. Also, the bonding interfaces were analysed by means of optical microscopy, scanning electron microscopy and energy dispersive spectrometer. The bonding of Ti-6Al-4V to Cu was successfully achieved by diffusion bonding method. The maximum shear strength was found to be 2171 N for the specimen bonded at 890 degrees C for 60 min. The maximum hardness values were obtained from the area next to the interface in titanium side of the joint. The hardness values were found to decrease with increasing distance from the interface in titanium side while it remained constant in copper side. It was seen that the diffusion transition zone near the interface consists of various phases of beta Cu4Ti, Cu2Ti, Cu3Ti2, Cu4Ti3 and CuTi. (C) 2012 Elsevier Ltd. All rights reserved.
Fabrication and characterization of functionally graded material (FGM) structure containing two dissimilar steels (ER70S-6 and 308LSi) by wire arc additive manufacturing (WAAM)
(Elsevier, 2022) Ayan, Yusuf; Kahraman, Nizamettin
Functionally graded materials (FGM) are components that can provide different material properties in a single structure. It is sometimes required to exhibit locally different material behaviours from parts used for various purposes in the industry. In such requirements, the use of FGM structures emerges as a solution. The fabrication of FGM structures with traditional manufacturing methods is generally complicated and sometimes not possible. However, the additive manufacturing (AM) technique, which is the topic of many applications and research today, has emerged as a superior manufacturing method compared to traditional methods in fabrication FGM structures, thanks to its advantages. Fabrication in the form of layers with the AM allows the fabrication of layers with varying material properties. This study was carried out on the fabrication of FGM structures by the wire arc additive manufacturing (WAAM) method, which is one of the metal AM techniques. Low alloy steel (ER70S-6) and austenitic stainless steel (308LSi) metal wires are used in FGM structures. The FGM structure was success-fully fabricated by the WAAM method. Hardness, tensile, and fatigue tests were applied to determine the me-chanical properties of the part. In addition, XRD analysis and microstructure studies were carried out to understand the metallurgical properties. As a result of the mechanical tests, no defects were observed in the FGM interfaces, and an increase of up to 46% was observed in the tensile strength compared to the single-material fabrication. In hardness measurements and microstructure studies, it has been observed that the FGM struc-ture exhibits different properties according to the changing layers. It has been concluded that the fatigue limit of the FGM part in the horizontal direction is 25% higher than in the vertical direction.
Fabrication and Fatigue Properties of Dissimilar Steel Functionally Graded Material Structure Through Wire Arc Additive Manufacturing
(Springer, 2023) Ayan, Yusuf; Kahraman, Nizamettin
Functionally graded materials (FGM) are structures that can provide different material properties together. To produce these structures, the additive manufacturing method has been used and preferred. In this study, an FGM structure was fabricated by wire arc additive manufacturing (WAAM) process using low-alloy ER70S-6 and austenitic stainless steel 308LSi metal wires. The FGM structure was characterized by tensile, fatigue, hardness tests, and microstructure examinations. As a result of the applied tests, it was found that the FGM structure has strong interfacial strength. In addition, no formations or defects that could reduce the strength of the FGM part were observed at the interface and in the regions close to the interface. The sides of the FGM part containing the base material could reflect their characteristic material properties. FGM part, whose properties can be changed partially, has been successfully fabricated.

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