Yazar "Yildirim, Mehmet Serkan" seçeneğine göre listele

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    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.
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    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.
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    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.
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    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.