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    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.
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    Flux cored arc welding on 30MnB5 steels used in agricultural mechanisation: microstructure evolutions and mechanical properties
    (Springer India, 2021) Cevik, Bekir; Sahin, Omer; Gulenc, Behcet
    30MnB5 steel has taken its rightful place among the materials used in agricultural mechanisation industry due to its excellent mechanical properties. 30MnB5 steel is widely used especially in structural parts requiring hardness, strength and wear resistance. The increasing importance of economic factors in today's industry requires the production of long-lasting agricultural machineries in agricultural mechanisation. Agricultural machinery systems are set-up by assembling the materials used in agricultural mechanisation industry with each other. Therefore, it is important to apply welding process to this steel used in agricultural mechanisation. The number of studies on the use of various welding methods and consumables (electrode, welding wire, shielding gas, etc.) in welding of steels used in agricultural mechanisation continues increasingly today. Flux-cored arc welding technology is one of welding methods that have been mostly studied in recent years and are applied on various metals. In this study, 30MnB5 steel sheets were flux-cored arc welded using rutile and basic flux-cored wires in 100% CO2 atmosphere. Bending, impact, and hardness tests and metallographic examinations were carried out in order to determine the mechanical and microstructural properties of the welded samples. As a result of the microstructure studies, structures such as grain boundary ferrite, widmanstatten ferrite, acicular ferrite, bainite, and martensite were determined in the weld metal and HAZ. As a result of the hardness test, hardness distribution in the form of M was determined in the weld zones. The bending and impact tests indicated that the highest mechanical properties were obtained from the weld seams welded with basic flux-cored wire.
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    Manual metal arc welding of dissimilar 30MnB5 and S 235 low alloyed steels for agricultural applications
    (Walter De Gruyter Gmbh, 2021) Cevik, Bekir
    In agricultural mechanization industry, different types of materials are assembled with each other to establish agricultural machine systems. However, the necessity of joining dissimilar materials used in the same machine system may cause some problems. Joining two different materials by welding and selecting the most appropriate weld metal ( electrode) for this is a very difficult problem. The increasing importance of the economic factors in today's industry requires both the use of dissimilar materials in agricultural mechanization and the production of longer-lasting agricultural machines, thus making it necessary to use dissimilar steels in agricultural mechanization systems. Therefore, it is important to apply a welding process to dissimilar steels used in agricultural mechanization. In this study, 30MnB5/S235 steel pairs were joined by the manual metal arc welding (MMAW) method using different covered electrodes. In order to determine the mechanical properties of the welded samples, hardness, bending, and impact tests were carried out. In addition, visual inspection to the weld seams, liquid penetrant testing, and metal-lographic examinations to determine the microstructural properties were conducted. As a result of the microstructure studies, structures such as grain boundary ferrite, Widmanstatten ferrite, acicular ferrite, bainite, and martensite were determined in the weld metal and HAZs. As a result of the hardness test, the highest hardness values were determined in HAZs on the side of 30MnB5 steel. As a result of the bending test, the highest mechanical properties were obtained in the weld seams made with basic flux-cored wire. As a result of the notch impact test, the highest mechanical properties were obtained in the weld seams made with basic flux-cored wire, after the base metals.
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    Production and characterization of waste walnut shell powder that can be used as a sustainable eco-friendly reinforcement in biocomposites
    (Walter De Gruyter Gmbh, 2024) Cevik, Bekir; Avsar, Yuecel
    The rapid depletion of natural resources and the increase of environmental problems due to production-related waste necessitate sustainable waste management. In particular, reintroducing by-products and waste generated by agricultural activities into the economy is critical to reduce environmental pollution, solve the storage problem, and promote sustainability. Agricultural wastes such as fiber, husks, cobs, stalks, straw, dust, and particles are recyclable and can be innovatively reused in various sectors. One of the innovative fields where sustainable agricultural waste management can be implemented is the development of biocomposites. One of the most important steps in the production of biocomposites reinforced with agricultural waste is processing the waste biomass and making it usable as a reinforcing element. This study investigated the production of powder reinforcements for biocomposite material from the biomass of walnut shells using a ring mill. The walnut shells, mechanically reduced in size, were first dried at 100 degrees C for 3 h and ground at four different grinding times (10, 20, 30, and 40 min). Afterward, the waste walnut shell powders were subjected to sieve analysis and precise weight measurements. Then, the waste walnut shell powders, which were dried at 100 degrees C for 3 h and ground for 40 min, were subjected to a second drying process at 100 degrees C (60, 180, and 300 min) and ground again for 40 min. Then, the resulting waste walnut shell powders were subjected to sieve analysis, precision weight measurements, and microscopic, and SEM analyses to determine the characterization of the powders.
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    Weldability of dissimilar stainless steels by MIG welding with different gas combinations
    (Springer India, 2023) Acar, Ismail; Cevik, Bekir; Gulenc, Behcet
    Stainless steels have been increasingly used for agricultural and food processing, biogas, architecture, automotive, machine-manufacturing, biomedicine, chemical, and petrochemical industry due to their corrosion resistance and sanitary qualities. Dissimilar stainless steels may need to be utilized together in various fields due to their different properties. Therefore, it is important to weld dissimilar stainless steel, which are employed in these fields, with strong mechanical properties. However, the requirement to join many metals, each of which has different properties, on the same construction may result in the emergence of some problems. The properties of the weld zone as well as the quality of the welded joints depend on the selection of the optimal welding parameters and the kind of shielding gas. Therefore, estimating the quality and service life of dissimilar stainless steel joints requires to understand the weld zone's properties better. Therefore, it is important to investigate the effect of shielding gases and gas combinations on the welding of dissimilar stainless steels in the welding process. In this study, AISI 316 austenitic stainless steel and AISI 430 ferritic stainless steel were joined utilizing the metal inert gas (MIG) welding with different shielding gas combinations. In welding processes, 100% Ar, 97% Ar+3% H-2, and 93% Ar+7% H-2 gas combinations were used. The welded sheets were subjected to hardness, tensile, and bending tests in addition to metallographic testing. The effects of the shielding gas combinations on the mechanical and microstructural properties of AISI 316 austenitic and AISI 430 ferritic stainless steel connections were investigated through these tests.