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Aisi 304 ve aisi 430 paslanmaz çeliklerin tig, mig ve örtülü elektrod ark kaynağıyla birleştirilebilirliğinin araştırılması
(2010) Kaya, Yakup
Bu çalışmada, 3 mm kalınlığında AISI 304 ostenit paslanmaz çelik levha ile aynı kalınlıkta AISI 430 ferritikpaslanmaz çelik levhalar TIG (Tungsten Inert Gas), MIG (Metal Inert Gas) ve Örtülü elektrod ark kaynakyöntemleri ile birleştirilmiş ve birleştirilen malzemelerin çekme dayanımı, çentik darbe dayanımı, mikrosertlikve mikroyapı özellikleri incelenmiştir. Çekme testleri sonucunda tüm numunelerde kopma birleştirmenin ferritikpaslanmaz çelik esas metal tarafında ve kaynak metaline yakın olan Isı Tesiri Altındaki Bölge (ITAB)’ degerçekleşmiştir. Kaynaklı bağlantılarda en yüksek çekme dayanımı ise TIG kaynağı ile birleştirilmişbağlantılardan elde edilmiştir. Çentik darbe testlerinde, TIG ve MIG kaynağı ile birleştirilmiş bağlantıların çentikdarbe kırılma enerjileri, ark kaynağı ile birleştirilmiş bağlantılardan yüksek ölçülmüştür. Mikrosertlik testlerisonucunda, tüm kaynak yöntemlerinde en yüksek sertlik değeri AISI 430 ferritik paslanmaz çelik esas metaltarafında kaynak metaline yakın olan ITAB’ da ölçülmüştür. Mikroyapı incelemelerinde, AISI 430 ferritikpaslanmaz çeliğin ITAB bölgesinde belirgin bir tane irileşmesinin meydana geldiği tespit edilmiştir.
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.
Application of Submerged Arc Welding at Different Amperages in the Manufacture of Storage Tanks and Examination of the Weld Zone
(Gazi Univ, 2024) Atilgan, Yigitcan; Yildirim, Mehmet Serkan; Kaya, Yakup
In the study, ASTM A36 steel materials were combined with submerged arc welding using different amperages. Non-destructive magnetic particle (MT), liquid penetrant (SP), radiographic (RT), and ultrasonic (UT) examinations were performed on the joints. In addition, optical microscope, microhardness, bending, tensile, and notch impact tests were carried out on the welds. As a result of the RT and UT examinations, a lack of root penetration was found in the welds made at 450 A and 475 A. In the optical microscope examinations, the areas formed by the HAZ-weld metal transition were found to have a similar appearance for each amperage. In the microhardness studies, the hardness values are listed as weld metal, HAZ, and base material from high to low. From the notch impact tests, it was found that increasing the temperature increased the toughness value. From the bending tests performed on the joints where 450A and 475A were used, it was found that cracks and tears occurred. In addition, a rupture occurred in the weld metal during the tensile tests conducted on the joints made at 450 A and 475 A. For the joints made at other amperage values, it occurred in the base material.
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.
Effect of heat treatment on interface characteristics and mechanical properties of explosive welded Cu/Ti composites
(Walter de Gruyter GmbH, 2024-12-09) Yıldırım, Mehmet Serkan; Kaya, Yakup
Copper and titanium plates were used in the studies. Explosive welding (EW) processes were carried out using different explosive rates. The resulting composite plates were heat treated at different temperatures. Various tests were then carried out on samples with and nonheat treatment. In the SEM studies, it was observed that a flat interface shape was formed in the joints where the lowest explosive rate (R = 2.5) was used, but as the explosive rate increased, the interface shape became wavy. It was also found that a thickening diffusion layer formed as the heat treatment temperature increased. As a result of XRD and EDS analyses, it was found that Cu4Ti, CuTi2, CuTi, CuTi3, Cu3Ti2, and Cu4Ti3 intermetallic phases could be formed because of the high explosive rate and heat treatment applications. Increasing the amount of explosives increased the tensile-shear strength. However, the heat treatment applied reduced the strength values. No defects were detected in the bending tests performed on all heat-Treated and nonheat-Treated 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.
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.
Grade a gemi sacının örtülü elektrod ark kaynak yöntemi ile sualtı ve atmosferik şartlarda birleştirilebilirliğinin araştırılması
(2018) Imdat, Kadir; Kaya, Yakup; Kahraman, Nizamettin
Bu çalışmada, Grade A gemi sacı, örtülü elektrodla ark kaynak yöntemi ile, parafin kaplanmış E 6013 standardına sahip rutil örtü tipli elektrodla, atmosferik şartlarda ve su altında farklı derinliklerde birleştirilmiştir. Kaynaklı birleştirmelerin mekanik özelliklerini belirlemek için sertlik deneyi ve çekme testleri yapılmıştır. Ayrıca kaynak bölgesinde meydana gelen yapısal değişim ve dönüşümleri gözlemlemek için kaynaklı numuneler üzerinde mikroyapı çalışmaları gerçekleştirilmiştir. Yapılan sertlik testleri sonucunda, en yüksek sertlik değerleri kaynak metalinden ölçülürken onu sırasıyla ısının tesiri altında kalan bölge (ITAB) ve ana malzeme takip etmektedir. Yapılan çekme testleri sonucunda, tüm numunelerde kopma kaynak metalinde gerçekleşmiş ve bütün bağlantı dayanımları, ana malzemeden düşük bulunmuştur. Mikroyapı incelemelerinde ilk pasoların ince taneli izotrop, dış kapakları oluşturan son pasoların ise ince sütunsal taneli olduğu gözlenmiştir. Ayrıca su altında birleştirilen numunelerde hızlı soğumadan kaynaklı martenzitik dönüşüm olduğu mikroyapı incelemelerinde gözlenmiştir. Deney sonuçları genel olarak değerlendirildiğinde, sualtı ark kaynak yöntemiyle birleştirilen numunelerin atmosferik şartlarda birleştirilen numuneye göre uzama değerlerinde yaklaşık % 30, çekmede ise yaklaşık % 12 daha düşük dayanım sergiledikleri gözlemlenmiştir.
An investigation into the explosive welding/cladding of Grade A ship steel/AISI 316L austenitic stainless steel
(Elsevier Sci Ltd, 2013) Kaya, Yakup; Kahraman, Nizamettin
In this study, Grade A ship steel sheet (parent sheet) to AISI 316L austenitic stainless steel sheet (flyer sheet) used in offshore and ship building were cladded through explosive cladding at various explosive ratios. The effect of explosive ratio on the cladded joint interface was investigated. For this purpose, tensile-shear, impact toughness, bending, microhardness properties and microstructure of the explosively cladded joints were examined. Tensile-shearing tests results showed that shear and fracture took place in the AISI 316L sheet not in the joining interface. The impact toughness of the explosively cladded specimens at room temperatures was found significantly higher than that of parent sheet (Grade A) because of the high impact toughness of AISI 316L austenitic stainless steel layer. No separation was observed in the joint interface of the explosively cladded sheets after three-point bending. Hardness values of the explosively cladded joint increased with increasing explosive ratio and the highest hardness values were obtained near the interface. Microstructural examination showed that increasing explosive ratio transformed the cladding interface from smooth to wavy shape. Moreover, with increasing explosive ratio, the wavelength and amplitude of the waviness increased. It was also observed that grains near the interface were elongated parallel to the explosion direction. Consequently, mechanical properties of Grade A ship sheet can be increased by explosive cladding with AISI 316L austenitic stainless steel. (C) 2013 Elsevier Ltd. All rights reserved.
AN INVESTIGATION INTO THE JOINING OF TITANIUM WITH COPPER THROUGH DIFFUSION WELDING/BONDING
(Gazi Univ, Fac Engineering Architecture, 2013) Aydin, Kemal; Hidiroglu, Mehtap; Kaya, Yakup; Kahraman, Nizamettin
In this study, Ti-6Al-4V and copper were joined through different welding temperatures (825 and 850 degrees C) and holding time (15, 30 and 60 min) diffusion welding/bonding method under argon shielding. The welded joints were subjected to hardness and shearing tests in order to determine their interfacial strength. In addition, microstructural properties of the joined interface were examined using optical and scanning electron microscope (SEM). EDS graphs and diffusion maps of the interface were obtained by carrying out line and elemental analyses. The shearing tests revealed that increasing welding temperature and holding time increased the shearing strength of joined parts. The hardness tests indicated that hardness values increased with increasing distance from titanium to the interface and decreased with increasing distance from the interface to the copper. EDS analyses showed that different reaction areas took place in the welded parts depending on the temperature and holding time.
Investigation of Copper-Aluminium Composite Materials Produced by Explosive Welding
(Mdpi, 2018) Kaya, Yakup
Aluminium and copper are two metals frequently used in the automotive and aerospace industries due to their properties of lightness and high conductivity. In this study, copper and aluminium plates were joined using the explosive welding method. The effects of the explosive ratio on the properties of the bonding interface were investigated. Results of the experimental studies showed that the bonding interface changed from a slightly wavy structure to a completely wavy structure as the explosive ratio was increased. It was found that due to the cold deformation resulting from the collision of the flyer and parent plates during the explosion, there was an increase in the hardness values near the bonding interface and on the outer surfaces of the plates. The increase in deformation hardening along with the increasing explosive ratios led to the reduced impact toughness of the composites. In the results of the tensile-shear and bending tests, no separation or fracturing was seen in the bonding interfaces at any of the explosive ratios. As a result, it was seen that the explosive welding method can be used in combining copper and aluminium materials.
An Investigation of Joinability of S235JR and S355JR Construction Steel by MAG Welding Method with Cored Wire Electrode
(Gazi Univ, 2018) Kaya, Yakup
In this study, S235JR and S355JR construction steel plates with 3 mm thickness both were joined using cored wire electrode type filler metal by MAG welding method. Joined materials between themselves (S235JR-S235JR, S355JR-S355JR) and different (S235JR-S355JR) were carried out in three different combinations including. Welding operations of these steels was carried out in 3 different combinations with each other (S235JR-S235JR, S355JR-S355JR) and with each other (S235JR-S355JR). The mechanical and microstructure properties of the welded samples were investigated. As a result of tensile tests, fracture occurred on main materials for S235JR-S235JR and S355JR-S355JR joints and occurred on S235JR side for S235JR-S355JR joints. No crack or separation was observed in all joined samples during 180 degrees bending tests in both directions. As a result of the microhardness tests, it was measured from the highest hardness weld metal in all joining combinations, followed by ITAB and main material. In the microstructure studies, it was determined that the whole of the samples came to the grain growth from the main material to the welding metal.
Investigation of The Joining Interface of Copper-Titanium Bimetallic Composite Materials Manufactured Using Explosive Welding Method
(Gazi Univ, 2024) Yildirim, Mehmet Serkan; Kaya, Yakup
In this study, copper (Cu) and titanium (Ti)plates were joined by explosion welding method using different explosive rates and Cu-Ti bimetallic composite materials were produced. The effect of explosive rate on the bonding interface of the produced Cu-Ti bimetallic composite materials was invistigated by microstructure studies and mechanical tests. Optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) methods were used for the joining interface characterization. In order to determine the mechanical properties of the joining interface, tensile-shear, notch impact, bending, twisting tests and microllardness studies were carried out. As a result of the microstructure investigations, it was determined that as the exposive rate increased, the fluctuation at the bonding interface increased and accordingly, the wavelength and amplitude increased. In addition, it was determined that Cu4Ti and Cu4Ti3 intermetallic phases were formed at an explosive rate of R=3, and intermetallic phases of Cu3Ti2, Cu4Ti3, CuTi2 and CuTi3 at an explosive rate of R=3.5. As a result of the mechanical tests, it was determined that there was no visible welding defect at the bonding interface.
Investigation of the Microstructural, Mechanical and Corrosion Properties of Grade A Ship Steel-Duplex Stainless Steel Composites Produced via Explosive Welding
(Springer, 2017) Kaya, Yakup; Kahraman, Nizamettin; Durgutlu, Ahmet; Gulenc, Behcet
Grade A ship-building steel-AISI 2304 duplex stainless steel composite plates were manufactured via explosive welding. The AISI 2304 plates were used to clad the Grade A plates. Optical microscopy studies were conducted on the joining interface for characterization of the manufactured composite plates. Notch impact, tensile-shear, microhardness, bending and twisting tests were carried out to determine the mechanical properties of the composites. In addition, the surfaces of fractured samples were examined by scanning electron microscopy (SEM), and neutral salt spray (NSS) and potentiodynamic polarization tests were performed to examine corrosion behavior. Near the explosion zone, the interface was completely flat, but became wavy as the distance from the explosion zone increased. The notch impact tests indicated that the impact strength of the composites decreased with increasing distance from the explosion zone. The SEM studies detected brittle behavior below the impact transition temperature and ductile behavior above this temperature. Microhardness tests revealed that the hardness values increased with increasing distance from the explosion zone and mechanical tests showed that no visible cracking or separation had occurred on the joining interface. The NSS and potentiodynamic polarization tests determined that the AISI 2304 exhibited higher corrosion resistance than the Grade A steel.
An Investigation on Joinability of Grade A Ship Steel Through Shielded Metal Arc Welding Method in Underwater and Atmospheric Conditions
(Gazi Univ, 2018) Imdat, Kadir; Kaya, Yakup; Kahraman, Nizamettin
In this study, Grade A ship steel was joined at both the atmospheric conditions and underwater at various depths through shielded metal arc welding method using paraffin coated shielded rutile type electrode conforming to E 6013 standard. In order to determine the mechanical properties of welded joints hardness and tensile tests were carried out. In addition, microstructural examinations were performed on the welded specimens in order to observe structural the changes and transformations occurring in the welding zone. The hardness test results showed that the highest hardness values are seen for the weld metal and these are followed by heat affected zone (HAZ) and base material. After the tensile tests, it was seen that all the specimens fractured at the meld metal and that strength of the joints lower than that of base material. It was observed from the microstructural examinations that first passes are fine grained isotropic while the last passes are fine grained columnar. In addition, martensitic transformation due to rapid cooling was seen in the specimens joined at underwater. When the experimental results are generally evaluated, it is seen that the specimens joined through underwater arc welding method exhibited 30 % lower elongation and 12 % lower tensile strength than those joined at the atmospheric conditions.
AN INVESTIGATION ON JOINABILITY OF THE AISI 304 AND AISI 430 STAINLESS STEEL BY TIG, MIG AND SHIELDED METAL ARC WELDING METHODS
(Gazi Univ, Fac Engineering Architecture, 2010) Kaya, Yakup
In this study, AISI 430 ferritic stainless steel and AISI 304 austenitic stainless steel sheets with 3 mm thickness were joined by Tungsten Inert Gas (TIG), Metal Inert Gas (MIG) and shielded metal arc welding methods. Mechanical properties of the welded samples were investigated in terms of tensile strength, notch impact strength, microhardness and microstructure. The results of the tensile test indicated that fracture occurred at the HAZ of the ferritic stainless steel side in the all samples. The highest tensile strength in welded samples were obtained in the samples joined with TIG welding. According to the notch impact test, impact energy of the samples joined with TIG and MIG is higher than that of the samples joined with shielded metal arc welding. Microhardness test showed that the highest hardness was obtained in the HAZ at the AISI 430 stainless steel for all welding condition used in this work. According to microstructure investigation, it was observed that grain growth occurred in the HAZ of the AISI 430 ferritic stainless steel.
Joining of pressure vessel steels using MAG welding method and investigation of mechanical properties
(Gazi Univ, 2024) Yalcin, Ferhat; Yildirim, Mehmet Serkan; Kaya, Yakup
In this study, P265GH and P355NH steels, which are mostly used in pressure vessel production, were joined by MAG welding. Visual (VT), radiographic (RT) and ultrasonic (UT) examinations, as well as optical microscope, microhardness, tensile, notch impact and bending examinations were carried out in the welding areas of the obtained joints. No errors out of tolerance were detected in visual inspection practices. In addition, no discontinuity was detected in the welded samples during radiographic and ultrasonic examinations. In the microstructural examinations, the formation of large and columnar-shaped weld metal grains oriented in the direction of heat flow was observed. In addition, in the microhardness measurements, the highest hardness value was obtained in the weld metal, followed by HAZ and the main material, respectively. In all tensile tests, ductile necking and rupture occurred from the main material. In the notch impact tests performed, it was determined that the impact toughness value of the HAZ region was higher than that of the weld metal. In bending tests, no visible defects were detected in the welded samples.
Joint properties and microstructure of diffusion-bonded grade 2 titanium to AISI 430 ferritic stainless steel using pure Ni interlayer
(Springer London Ltd, 2016) Yildiz, Aydan; Kaya, Yakup; Kahraman, Nizamettin
Diffusion welding/bonding has been successfully used to joint dissimilar metals widely. In this study, pure Ti and AISI 430 ferritic stainless steel plates were joined through diffusion welding using a Ni interlayer at various temperatures (800, 825, 850 and 875 A degrees C), holding times (15, 30, 60 and 120 min) and under a constant pressure (3 MPa) under argon shielding media. The welded joints were subjected to tensile-shear tests and hardness tests in order to determine their interfacial strength. In addition, microstructural properties of the joined interface were examined using optical and scanning electron microscope (SEM). The tensile-shear test results showed that the fractures occurred mostly in the interface of the Ni-ferritic stainless steel web at lower temperatures. It was seen from the hardness results that the highest hardness value was obtained for the titanium side and the hardness values increased with increasing welding temperature and holding time. SEM/EDS examinations showed that the diffused atoms and diffusion distance increased depending on the increasing temperature and holding time.
Mechanical Properties and Corrosion Behaviour of Copper/Titanium Composite Plates made by Explosive Welding after Heat Treatment
(Springer India, 2024) Yildirim, Mehmet Serkan; Kaya, Yakup
Copper and titanium plates were used in the studies. These plates were joined together by explosive welding using different amounts of explosives. The resulting composite plates were heat-treated at different temperatures. In microstructural studies, it was observed that the joints with the least rate of explosive used had an almost flat joint interface and as the explosive rate increased, a wavy structure was formed. Hardness values were found to increase as the rate of explosives increased, but hardness values decreased after heat treatment. It was observed that notch impact strength decreased with increasing explosive rate, but there was an increase in impact toughness values after heat treatment. Torsional testing of all specimens revealed no visible defects. Neutral salt spray tests showed that the copper surfaces of the composite plates corroded, but there was no corrosion on the titanium side.

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