Browsing by Publisher "Carl Hanser Verlag"
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Item Fracture behavior of overmatched ductile iron weldment(Carl Hanser Verlag, 2007) Cetinel H.The fracture behavior of welded ductile iron is discussed by means of experimental and theoretical studies. Ferritic nodular cast irons were joined by cold arc welding in order to obtain over-matched weldment in which the yield strength of the weld metal is higher than that of the base metal. As a result of the welding process, various regions with different mechanical properties formed in the welded specimens. In the experimental part of the study, the mechanical properties of the different regions in the welded specimens were identified and J-Integral toughness values were determined by fracture toughness tests for different crack locations including the base metal, the heat affected zone and the weld metal. In the numerical part of the study, finite element analyses were conducted by fixing 3-D models precracked at different locations for different crack lengths. In these models, after stress-strain analysis, stress triaxiality and plastic deformation characteristics around the crack tip were determined for each crack location and different crack sizes. It was found that stress triaxiality values increase with growing crack length. Different regions with different strength levels in the weldment affect the extension of plastic deformation in the models. Hindrance to the extension of plastic deformation at the heat affected zone and diffusion line causes an extra increase in stress triaxiality at the crack tip.Item Fracture behavior of overmatched ductile iron weldment(Carl Hanser Verlag, 2007) Cetinel H.The fracture behavior of welded ductile iron is discussed by means of experimental and theoretical studies. Ferritic nodular cast irons were joined by cold arc welding in order to obtain over-matched weldment in which the yield strength of the weld metal is higher than that of the base metal. As a result of the welding process, various regions with different mechanical properties formed in the welded specimens. In the experimental part of the study, the mechanical properties of the different regions in the welded specimens were identified and J-Integral toughness values were determined by fracture toughness tests for different crack locations including the base metal, the heat affected zone and the weld metal. In the numerical part of the study, finite element analyses were conducted by fixing 3-D models precracked at different locations for different crack lengths. In these models, after stress-strain analysis, stress triaxiality and plastic deformation characteristics around the crack tip were determined for each crack location and different crack sizes. It was found that stress triaxiality values increase with growing crack length. Different regions with different strength levels in the weldment affect the extension of plastic deformation in the models. Hindrance to the extension of plastic deformation at the heat affected zone and diffusion line causes an extra increase in stress triaxiality at the crack tip.Item Investigation of the influence of the pre-aging process on the hardness of 6082 and 7075 aluminum alloys(Carl Hanser Verlag, 2012) Şahin S.; Durmu H.; Yüksel N.; Manisa M.In this study, the effect of pre-aging time and temperature on mechanical properties of aluminium alloys 6082 and 7075 has been investigated. Pre-aging has been applied at 50, 60, 70 and 80 °C for 24, 72, 144 hours after solution treatment process at 560 °C for 1 hour. Then these samples have been subjected to an aging process at 180 °C and 125 °C. The hardness of samples has been measured during aging process regularly. Eventually, it was determined that if pre-aging process is performed at low temperature, an increase of hardness occurs and hardness decreases with increasing temperature during aging. © Carl Hanser Verlag, München.Item Microstructural and mechanical properties of pure aluminunn, 5083 and 7075 alloys joined by friction stir welding(Carl Hanser Verlag, 2012) Yilmaz S.S.In this study, microstructural and mechanical properties of pure alu-minum, 5083 and 7075 alloys joined by friction stir welding were inves-tigated. Hardness, tensile, bending and impact tests were applied to the welded samples. In addition, optical and SEM tests were carried out. The effects of welding speed on microstructure and mechanical properties were investigated in these materials. Then, the optimal conditions for friction stir welding were determined for pure aluminum, 5083 and 7075 alloys. The maximum hardness was observed for 7075 while the minimum hardness was observed for pure aluminum. © Car Hanser Verlag, München.Item The effect of the retrogression process on the wear behaviour of a 7075 aluminium alloy(Carl Hanser Verlag, 2012) Durmus H.; Uzun R.O.; Şahin S.; Yüksel N.Retrogression and re-aging (RRA) process are applied in an attempt to enhance mechanical properties and corrosion resistance of 7075 aluminium alloys. In this study, retrogression and re-aging process have been applied to a 7075 aluminium alloy at 170 °C for 5, 40, 80 min and wear resistance of RRA applied samples have been investigated by ball-on-disc wear test apparatus. Sliding distance has been chosen as 300 meters. Re-aging procedure has been carried out at 125 °C for 10, 20 and 30 hours. Minimum wear loss has been obtained by retrogression for 40 min and aging for 30 hours. © Carl Hanser Veriag, München.Item Investigation of the element diffusion in friction welded X53CrMnNiN219 and X45CrSi93 steels(Carl Hanser Verlag, 2014) Uzkut M.; Un̈lü B.S.; Yavuz M.; Akdag M.In this study, high alloyed steel bars with a diameter of 12.30 mm made up of 1.4871 (X53CrMnNiN219) and 1.4718 (X45CrSi93) steels were used as experimental material for friction welding. Metallographie and X-ray diffraction investigations as well as microprobe sampling were performed on the samples. Mechanical orientation of particles caused by plastic deformation and carbide scattering has been observed. The diffusion behaviour has been investigated for the elements Cr, Ni, Mn, and Si, respectively. The existence of (Cr,Fe) 7C3 carbides in the welding region was also observed. © Carl Hanser Vpriai' GmhH & Co. KG.Item Mechanical properties of hot forged ANS11050 steel(Carl Hanser Verlag, 2014) Çavdar U.In this study, two different heating methods have been used for the hot forging process of ANSI 1050 steel. Some specimens were heated by induction generator at 250 kW, 3.2 kHz up to a temperature of 1250 °C ± 5 °C in 5 minutes under ambient conditions via a continuous conveyor belt system. Other steel specimens were heated continuously in a conventional furnace up to a temperature of 1230 °C ± 40 °C at ambient conditions in 30 minutes. All specimens were subjected to Charpy, three-point bending, fracture strain, and hardness tests (surface and cross-section measurements). Almost all mechanical test results were better for the specimens heated by the induction generator and also appeared as more stable than those for the specimens heated by conventional furnace which varying some showed results. Grain growing was found in the microstructure of the conventional heated specimens. Induction heated specimens were heated more homogenously than the conventional heated specimens which is the reason for more stable results. © Carl Hanser Verlag, München Materials Testing.Item Effects of surface finishing on the mechanical properties of induction welded iron based sintered compacts(Carl Hanser Verlag, 2014) Çavdar U.; Yalamac E.; Gülsahin I.In this study, iron based sintered parts were welded by high frequency induction welding. The effects of surface roughness on the mechanical properties of induction welded samples were investigated. Polished and unpolished samples were welded and mechanically tested by three point bending test. The hardness of the samples increased from the base material towards the weld metal. The weld metal, heat affected zone and the base material of the samples were investigated by light microscopy. In contrast to the polished samples, corrosion attack was registered in the welded region of unpolished samples. According to the results, the welding duration affects the mechanical properties. However, the surface finishing process was the dominant factor for the bending strength of the welded samples. © Carl Hanser Verlag GmbH & Co. KG.Item Effects of ferroboron and ferrochromium powder addition on abrasive wear resistance of fe-based hardfacing coatings(Carl Hanser Verlag, 2014) Yüksel N.; Şahin S.Ferrochromium is used in hardfacing alloys as carbide former. In this study, ferroboron was used with ferrochromium to investigate the effect on microstructure and wear resistance. Five different hardfacing alloys (50 % massive welding wire + 50 % powder mixture) were produced by open arc welding on AISI 1020 steel. Microstructure, SEM and XRD analysis, hardness test, and dry sand/rubber wheel abrasion test were carried out. According to the test results, as the amount of ferroboron increased, wear rate decreased. Minimum wear rate was obtained in 100 % ferroboron powder added sample. © Carl Hanser Verlag GmbH & Co. KG.Item Investigation of mechanical properties and impact strength depending on the number of fiber layers in glass fiber-reinforced polyester matrix composite materials(Carl Hanser Verlag, 2014) Turkmen I.; Koksal N.S.In this study, glass fiber-reinforced composite materials were produced by hand lay-up with different number of layers of glass fiber, and tensile, flexural and impact fatigue strength of composite materials were investigated. The samples were also metallographically characterized. Depending on the number of fiber layers of samples mechanical properties and impact fatigue strength were examined. Due to the increase in the number of fiber layers, the mechanical properties of the samples were found to be improved. © Carl Hanser Verlag GmbH & Co KG.Item The effect of aging parameters and roughness on the wear properties of aluminum alloy 6082(Carl Hanser Verlag, 2014) Cetinel H.; Ayvaz M.The aim of this study was to investigate the influence of aging parameters and initial roughness on the wear properties of the aluminum alloy AA 6082 (Al-Mg-Si). For this purpose, various heat treatments were carried out. Afterwards, the solutionized samples and artificially aged samples (at 185 °C for 3 and 6 h) were prepared in terms of two different average surface roughnesses via various grades of grinding. The wear behavior of the samples was investigated by a pin-on-disc wear test apparatus under four different applied loads (5,10, 15 and 20 N) and five different sliding distances (250, 500, 750, 1000, 1250 and 1500 m). The sliding velocity was 30 cm × s-1. After the wear tests, the mass loss was measured for all samples and the worn surfaces were examined by scanning electron microscopy (SEM). The wear test results clearly show that with increasing hardness, the mass loss decreases, and the mass loss of the worn surfaces increases with increasing sliding distance, test load and initial roughness. © Carl Hanser Verlag GmbH & Co. KG.Item Wear behavior of fe-c-cr based hardfacing alloys dependent on ferrovanadium and ferrotungsten addition(Carl Hanser Verlag, 2014) Kapali G.; Şahin S.; Yüksel N.; Sargin F.; Yaman B.The aim of this study is to investigate the effect of vanadium and tungsten on wear behavior of Fe-C-Cr based hardfacing alloys. The wear behavior of hard-facing layers was determined by dry sand/rubber wheel abrasion tests according to ASTM G-65. The results of the abrasion tests were interpreted by metallographic examinations, SEM and EDX analyses as well as hardness measurements. According to the results of the experimental studies, the effect of W and V addition was discussed. © Carl Hanser Verlag GmbH & Co.Item Effects of coil design on induction welding of sintered iron based compacts(Carl Hanser Verlag, 2014) Çavdar U.; Kusoglu I.M.Sintered iron based compacts were welded by applying a high frequency induction process. The cross-sections of the compacts were square in shape so two different coil shapes, cylindrical and square, were studied with respect to the effect of magnetic flux. The effect of welding duration on the macrostructural changes and mechanical properties of the induction welded compacts were investigated for welding durations of 3, 5 and 10 minutes. © Carl Hanser Verlag GmbH & Co. KG.Item Microstructure and mechanical properties of aa 5083 and aa 6061 welds joined with aisi5 and aisi12wires(Carl Hanser Verlag, 2014) Cetine H.; Ayvaz M.Aluminum alloys are used in various industries including marine, defense, automotive, transportation and aerospace. Common to all of these industries is the need to join aluminum parts using fusion based welding processes. However, there are some difficulties in welding aluminum alloys, such as, for instance, hot cracking. In this study, the aluminum alloys 5083 and 6061 were welded using the TIG process and two filler wires (AlSil2 and AlSi5). Six different alloy combinations were investigated, i.e., 5083-AlSi5-5083, 5083-AlSi 12-5083, 6061-AJSi5-6061, 6061-AlSil2-6061, 5083-AlSi5-6061 and 5083-AlSi 12-6061. The mechanical properties of the samples were evaluated by microhardness scans, tensile tests as well as Charpy and three point bend tests. In addition, mi-crostructural investigations were performed by optical microscopy. © Carl Hanser Verlag GmbH & Co.Item Mechanical properties of dissimilar and similar cold metal transfer welded galvanized steel 1314 and aluminum aa1050(Carl Hanser Verlag, 2014) Irizalp A.O.; Durmus H.; Yüksel N.; Turkmen I.; Uzun O.This study aims to investigate the weldability of 1050 aluminum alloy (AA1050) and galvanized 1314 steel by the cold metal transfer (CMT) pro-cedur, comparing it with respective welding of similar aluminum sheets. Mechanical properties of welded specimens were determined by tensile testing and hardness measurements. The study was completed by microstructural analysis. The results showed that CMT welding can be applied successfully to join aluminum and steel. © Carl Hanser Verlag GmbH & Co.Item Effects of burnishing parameters on the quality and microhardness of flat die surfaces(Carl Hanser Verlag, 2015) Müftüoʇlu H.S.; Malyer E.In this study, the burnishing process is recommended as finishing operation of flat die surfaces for improving not only surface quality but also mechanical properties of milled die surfaces. This technique can be applied after milling operations in CNC milling centers with a single fastening that increases the accuracy of the die geometry. To determine both the usability of the process on flat die surfaces and the influence of process parameters, a simple burnishing tool with a fixed deformation element was designed and constructed. The CNC milling center was used for burnishing operations. The burnishing process was employed using a constant spindle speed on a flat surface. Burnishing feed rate, stepover, penetration depth, the number of passes, burnishing direction and coolant were chosen as process parameters. First, optimum parameters were stated, then macro and microstructure of the burnished surfaces were examined, and roughness and hardness measurements of surfaces were carried out. Results show that burnishing increased the surface quality and microhardness of flat milled surface. The penetra tion depth has the maximum and stepover has the minimum effect on surface quality. The coolant has the highest effect on microhardness. The burnishing direction has a significant effect on both microhardness and surface quality. It can be briefly stated that burnishing is an economic and feasible surface treatment process for finishing operations of die surfaces. © Carl Hanser Verlag, Münhen.Item Tribological properties of boronized ferrous based PM journal bearings(Carl Hanser Verlag, 2015) Ünlü B.S.; Yilmaz S.S.; Kurgan N.; Varol R.Ferrous based PM (powder metallurgical) materials are widely used in journal bearings since they provide a good tribological performance. These bearings are self-lubricating and can be used in places where lubricating is not possible. This also applies to the shaft material which shows adhesive wear. Tribological properties can be improved and adhesive wear can be decreased by boronizing. In this study, tribological properties of ferrous based boronized and non-boronized Fe-graphite, FeCu-graph-ite and CuSnFe-graphite bearings manufactured by PM method have been determined and compared. Boronizing treatment was carried out at 950°C for 4 hours. The SAE 1050 steel shaft was used as counter abrader. Experiments were carried out at 20 N loads and 1500 rpm every 30 minutes for 2.5 hours. © Carl Hanser Verlag, München. © Carl Hanser Verlag GmbH & Co. KG.Item Mechanical properties of conventionally and induction sintered Fe-based powder metal bushings(Carl Hanser Verlag, 2015) Çivi C.; Akpinar G.; Atik E.Mechanical properties of powder metal parts are directly related to the shape, distribution and the amount of pores. In this study, mechanical properties of induction sintered Fe based components were investigated dependent on the changing of sintering time and pore structures. For this purpose, compression tests were applied to sintered bushings and microstructural photographs were taken. The compression tests were accompanied by respective finite element analyses. The numerical values were compared to experimental results. It turned out that the micro-stress values were dependent on the amount and distribution of porosity. © Carl Hanser Verlag, München Materials Testing © Carl Hanser Verlag GmbH & Co. KG.Item Comparison of electrical energy consumption for different material processing procedures(Carl Hanser Verlag, 2016) Gokozan H.; Tastan M.; Taskin S.; Cavdar P.S.; Cavdar U.The aim of this study is to investigate the electrical energy consumption for different material processing methods. In these experiments, ferrous powder metals, bulk iron and bulk graphite materials are used. These different materials are heated, sintered and welded by using processes of ultra-high frequency induction heating (UHFIH), ultra-high frequency induction heating sintering (UHFIHS) and ultra-high frequency induction heating welding (UHFIHW), respectively. For all experiments, 2.8 kW, 900 kHz ultra-high frequency induction heating system is used. The experiments are conducted by LabVIEWTM based measurement and control system. Finally, all data are analyzed to show the energy efficiency of each process. © Carl Hanser Verlag GmbH &Co. KG.Item Corrosion resistance and mechanical properties of quenched and tempered 28MnCrB5 steel in two acidic environments(Carl Hanser Verlag, 2017) Yazici A.; Sadrettin Zeybek M.; Manisa; Güler H.; Izmir; Pinar A.M.; Tücer R.Korrosionwiderstand und mechanische Eigenschaften eines abgeschreckten 28MnCrB5-Stahles in zwei sauren Umgebungen. Die Mikrostruktur, die Härteverteilung, die Zugfestigkeit und das Bruchverhalten des angelassenen Stahles 28MnCrB5 wurden jeweils vor und nach Korrosionsversuchen untersucht. Das Korrosionsverhalten des angelassenen Stahles 28MnCrB5 wurde in zwei verschiedenen sauren Umgebungen analysiert, dabei wurde zum einen eine Salzsäurelösung mit einem 10 % molaren Anteil und zum anderen Döngemittel-haltige Erde verwendet. Die Proben wurden in beide Lösungen för 24, 48, 72, 96, 120, 144 und 168 Stunden und in die Döngemittel-haltige Erde zudem för 240 Tage getaucht. Es wurden die Korrosionsverluste mittels Gewichtsänderungsmessungen bestimmt und die entsprechenden Korrosionsraten berechnet. In der Probe des abgeschreckten Werkstoffes wurde vor und nach 168 Stunden in der Salzsäurelösung sowie in der Döngemittel-haltigen Erde duktiles Bruchverhalten beobachtet. Allerdings zeigte die Probe, die för 240 Tage der Korrosion in Döngemittel-haltiger Erde ausgesetzt war, sprödes Bruchverhalten und die Bruchoberfläche lies eine interkristalline Spaltbruchfläche erkennen. Nach dem 240-Tage-Korrosionsversuch in der Döngemittel-haltigen Erde nahm die Duktilität des Werkstoffes erheblich ab. Die Oberfläche der gehärteten Stahlproben wies am Ende des 168-Stunden-Korrosionsversuchs in Salzsäure Löcher, Risse und Abschälungen auf. Am Ende des 240-Tage-Tests in der Döngemittel-haltigen Erde zeigte die Oberfläche der Proben tiefe Abschälungen und Risse.