Browsing by Author "Uzkut M."
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Item Investigation of joining steel hard metal tips used in boring machines; [Sondaj matkaplarinda kullanilan sert metal uç-çeli̇k çi̇fti̇ni̇n bi̇rleşebi̇li̇rli̇ǧi̇ni̇n i̇ncelenmesi̇](1999) Uzkut M.; Köksal N.S.; Şahin S.The use of boring machines under highly varying working conditions for long periods requires a successful joining of material couples. If the joining is not performed successfully, hard metal tips will shorten the life of the boring machine by breaking off from the steel body. In addition, these broken hard metal tips deposited in the bore will affect later boring work negatively. For this reason, the quality of joining has a great significance from the economy and efficiency point of view. In this study, joining by brazing of 0.4% C steel with 9% Co bonder mixed wolfram carbide based hard metal tip used in boring machines is investigated. Joining by brazing of wolfram carbide based hard metal tip with 0.4% C steel is made under suitable temperature and pressure using suitable dekapan. The microhardness and metalographic investigation of steel, braze, and hard metal tip has been done in the joining region. In the metalographic investigations, it has been observed that, in the internal structure and hardness values of solder, diffusion from steel to solder and from solder to steel occurs. Also element diffusion from hard metal tip to solder layer takes place.Item Mechanical and metallurgical properties of brazed SAE 1040 and tungsten carbide(2002) Meric C.; Uzkut M.; Sahin S.[No abstract available]Item Investigation of effect of boronising on welding zone(2002) Meric C.; Sahin S.; Uzkut M.In the present study, AISI 1040 and AISI 8620 steels are joined by arc welding and gas metal arc welding, and then subjected to a solid boronising process at 850, 900, 950, and 1000°C using EKabor HM (tradename) for 4 h. The microhardness and thickness of the boride layers produced on the surfaces of the air cooled specimens are measured and the microstructures are photographed using optical microscopy. The effect of boronising in and around the welding zone is investigated.Item The determination of element diffusion in connecting SAE 1040/WC material by brazing(2005) Uzkut M.; Köksal N.S.; Ünlü B.S.This paper examines the element diffusions that take place in material when SAE 1040-WC materials are connected by brazing. During the brazing process, oxyacetylene fire was used and connected parts were cooled in air. On the connection zone, microhardness measurements and microprobe analyses were made. The hardness distribution in microhardness measurements on this zone shows the existence of element diffusion. Having performed line and surface micro probe analyses of various zones, postbrazing diffusions of Co and Ni elements were determined. © 2005 Published by Elsevier B.V.Item Residual stress analysis snd expansion of plastic zone in simple supported and clamped supported woven Ni-Cr reinforced thermoplastic matrix composite laminated plates(2007) Aykul H.; Uzkut M.In this study, a residual stress analysis is carried out on symmetric cross-ply and angle-ply thermoplastic simple supported and clamped supported laminated plates for transverse loading. Low density polyethylene thermoplastic matrix (LDPE) and woven NiCr fibers are used to produce the composite plates by using molds. First order shear deformation theory and nine nodes Lagrangian finite element are used. Mathematical formulation is given for the elasto-plastic stress analysis of a laminated plate for small deformations. Yield points and stresses are obtained for symmetric simple supported and clamped supported laminated plates. Residual stresses in thermoplastic plates are given in the tables. The expansion of plastic zones is illustrated for 50, 100 and 150 loading steps. Yield points and the expansion of plastic zones are compared for different plates. Mechanical properties of a layer are obtained experimentally. © 2007 SAGE Publications.Item Tribological behaviors of polymer-based particle-reinforced PTFE composite bearings(2010) Ünlü B.S.; Uzkut M.; Atik E.In this study, tribological behaviors of polymer-based particle-reinforced PTFE bearings have been investigated and evaluated. Tribological properties of these particle-reinforced PTFE composite bearings have improved two- or three-fold. © 2010 SAGE Publications.Item Determination of optimum welding parameters in connecting high alloyed X53CrMnNiN219 and X45CrSi93 steels by friction welding(Indian Academy of Sciences, 2011) Uzkut M.; Ünlü B.S.; Akdağ M.In this study, different welding parameters were applied to two different steels with high alloys and mechanical and metallographical investigations are performed. Thus, the optimum welding parameters were determined for these materials and working conditions. 12·30 diameter steel bars made up of 1·4871 (X53CrMnNiN219) and 1·4718 (X45CrSi93) steel were used as experimental material. The material loss increased with increase in friction and rotating pressure. No fracture at the welding region was observed and the highest fracture energy was identified in B5 group. Based on micro hardness investigation; the hardness profile reached its minimum value at the welding region. © Indian Academy of Sciences.Item Abrasive wear behaviour of SiCp-reinforced 2011 al-alloy composites(2013) Uzkut M.In this study, the abrasive wear behaviour of aluminium-alloy (Al-2011) SiC-particle-reinforced composites was investigated and compared with that of the matrix alloy. The experimental variables were the SiC-particle proportion, sliding distance and abrasive grit size. Al-2011 reinforced composites containing volume fractions (7, 14 and 21) % SiCp were fabricated with the vortex method. Sliding-wear tests were carried out using a pin-on-disc abrasive-test machine where a sample slides against a SiC abrasive of different grit sizes at a fixed speed, under the load of 4 N at room conditions. The results show that the wear resistance of the composites was significantly larger than that of the Al-2011 alloy; it increased with the increasing SiC-particle proportion and decreased with the increasing abrasive grit size.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 Microstructural properties of particle-reinforced polytetrafluoroethylene composite bearings after wear(Springer New York LLC, 2015) Ünlü B.S.; Uzkut M.; Pinar A.M.; Özdin K.High-performance engineering polymers that ensure the desired properties of journal bearings and give good wear results are investigated. We determine the microstructural properties of polymer-based particle-reinforced polytetrafluoroethylene composite bearings by analyzing the optical and SEM surface wear images. © 2015 Springer Science+Business Media New York.