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Öğe Investigate the effect of pre-drilling in friction drilling of A7075-T651(Taylor & Francis, 2014-04-28) Demir, Zülküf; Özek, CebeliFriction drilling is a non-traditional hole achieving method that is a clean, chip-less process, which is called thermal drilling, form drilling, flow drilling, and friction stir drilling. In this study pre-drilling friction drilling was investigated for improving the bushing shape of A7075-T651, which is a brittle cast material. During the process, surface roughness and bushing shapes were analyzed and generated frictional heat was measured by the virtue of thermocouples. Experiments were carried out to 4mm and 6mm in thicknesses of A7075-T651 aluminum alloy at 1200, 1800, 2400, 3000, and 3600 rpm spindle speeds, 20, 40, 60, 80, and 100 mm/min feed rates with using high-speed steel rotating conical tool, whose diameter is 8 mm. Consequently, the bushing shapes were advanced without cracks and petal formation in pre-drilling Friction drilling in comparison with without pre-drilling process. With increasing pre-drilled hole diameter the generated frictional heat was decreased. The achieved temperature was realized to be 1/2-1/3 of the melting temperature of the workpiece. Surface roughness values were decreased with decreasing or increasing both spindle speed and feed rate correspondingly.Öğe Effect of temperature, force, and vibration on fatigue strength of friction stir-welded AA7075 aluminum alloy joints(SpringerLink, 2021-01-04) Çelik, Yahya Hışman; Kılıçkap, Erol; Çetkin, EdipIn this study, the AA7075 alloy pairs were welded by friction stir welding method by using conical- and triangular-type stirrer pins. Welding forces and moments, vibration, and temperature values have been measured during the jointing depending on the welding parameters. Finally, microstructures were examined and mechanical tests were carried out. Results obtained from the experiments revealed that at low spindle speed and welding feed rates, the temperatures formed on the surface of the alloy pair were high, the vibrations were low, and the welding force and moments were partially high. When the microstructures of the welded areas are examined, it was determined that the conical mixing pin has a better microstructure than the triangular mixing pin. In addition, it was determined that the mechanical properties of welded joints having a good microstructure were quite good. As a result, it was observed that forces during welding, temperature of welding, and vibration values have an effect on microstructure and mechanical properties.Öğe Effect of climate change on some meteorological data: Batman example(ISITES, 2015) Karakaya, Hakan; Kallioğlu, Mehmet Ali; Yılmaz, AdemIncreasing Energy need in the global economy and tendency to utilization of poor quality fossil fuels have led to significant changes in world climate in recent years. Nowadays, global climate change has started taking part in the upper parts of the agenda. Human health, ecosystems even climate change evaluated as a problem to cause threat in terms of maintaining the human race have come forefront as basic ıssue of scientists and governments especially in recent years. In this study, an evaluation has been carried out about meteorological data of Batman Province, which has been developing rapidly in recent years and is located in the Southeastern Anatolian Region where climate change is felt severely. Within this context, meteorological data belonging to the years between 1993 and 2013 were provided by State Meteorology Affairs General Directorate. At twentyyear time, monthly average alterations of data in solar radiations, in wind power and in the amount of precipitation and temperature relations among them have been investigated by means of statistical analyses. As a result of the study, some significant changes in meteorological data of the region searched have been found and suggestions on solutions have been proposed.
