Yazar "Esme, Ugur" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • [ X ]
    Öğe
    Corrosion behavior of a dissimilar Inconel 625 superalloy and AISI 316L stainless steel weld
    (Walter De Gruyter Gmbh, 2025) Dokme, Fatih; Kulekci, Mustafa Kemal; Engin, Kaan Emre; Esme, Ugur
    Corrosion significantly impacts the welding of dissimilar components, leading to a decrease in the lifespan of products. The primary aim of this research is to examine the corrosion behavior of the weld region in dissimilar welding of Inconel 625 and AISI 316L plates with a thickness of 20 mm. The plates are weld together by using continuous current gas tungsten arc welding (CCGTA) and pulsed current gas tungsten arc welding (PCGTAW) methods. The process employs ERNiCr-3, TIG 316L, and a twisted combination of both filler metals (ERNiCr-3+TIG 316L). Specimens with dimensions of 12 mm x 20 mm x 42 mm are obtained by cutting the weld samples for corrosion tests. The divided parts are each submerged in a 100 ml pool of sulfuric acid and are maintained for a combined duration of 240 h. A weight loss investigation is undertaken, in addition to metallurgical characterizations of the specimens. Energy Dispersive Spectroscopy (EDS) in conjunction with Scanning Electron Microscopy (SEM) are utilized to conduct metallurgical investigations. It is observed that twisted filler metal and CCGTA welding method results in the highest amount of mass loss. The least corroded sample is obtained by using twisted filler metal combined with PCGTA welding method.
  • [ X ]
    Öğe
    Effects of ultrasonic welding parameters for solar collector applications
    (Carl Hanser Verlag, 2019) Yeniyil, Emre; Boga, Cem; Esme, Ugur
    Today, ultrasonic welding is used in many different areas due to ease of application compared to other welding methods. Computer, electric, automotive and aerospace industries are the leading areas for these applications. With its ability to easily join materials like Al, Cu, Ni, ultrasonic welding has become a preferred method for use in the welding of solar collectors which are components in solar energy systems. The system parameters for welding solar collectors must of course be adjusted according to the properties of the materials used so that the heat transfer between specimens is not affected. In this study, the selective coated plate and the heat carrier pipes of solar collectors were welded using ultrasonic seam welding, and the optimum welding parameters were determined according to the Cu-DHP copper alloy used. For this purpose, copper specimens were welded using welding speeds of 4, 8, 12 and 16 m x min(-1) and amplitudes of 4, 5 and 6 mu m, while pressure and frequency values were fixed. The shear strength values of these welded specimens were calculated, and images of the weld areas were obtained with the help of a scanning electron microscope. Through hardness measurements made on the interfacial region of the welds, it was concluded that optimal welding performance was obtained at an amplitude of 4 mu m and a welding speed of 12 m x min(-1). At these parameters, a mean shear strength value of 0.1386 MPa and a mean hardness value of 112 HV were measured.
  • [ X ]
    Öğe
    Hybrid Taguchi Based Grey Algorithm for Multi Objective Optimization of Gas Metal Arc Welded DP1000 Steel
    (2021) Karatas, Murat; Bayramoglu, Melih; Esme, Ugur; Geren, Necdet
    Euro-6 norms for reduction of CO2emissions and ECE-R66-01 regulation for safer passenger transportation became legislative obligations for bus builders. These two adaptations increase the weight of a bus as nearly 600kg which also increases the fuel consumption nearly 1.5-3%. Dual phase (DP) steels can compensate these increases by decreasing the thickness of the components. Because, ferrite provides the steel with good formability and martensite increases the hardness and ultimate tensile strength in DP steels. This study focused on the multi response hybrid optimization of gas metal arc welding (GMAW) of DP1000 steel to determine the optimal parametric combination which gives the maximum ultimate tensile strength (UTS, MPa) and joint efficiency (JE) under minimum heat input (Q, kj/mm). Nine experimental trials which is based on the orthogonal array suggested by Taguchi method was carried out to investigate objective functions for optimization in the experimental range of GMAW parameters such as voltage (U, volt), welding speed (V, mm/min) and wire feed rate (f, m/min). The Taguchi method continued with Grey Relational Analysis (GRA) to overcome the multiobjective optimization model. Finally, Analysis of variance (ANOVA) method has been used to determine the significance of the welding parameters on the responses of UTS, JE and Q. This shows flexible applicability of Taguchi based GRA to find out the effect of each GMAW process parameters onto individual responses.
  • [ X ]
    Öğe
    INVESTIGATION OF MECHANICAL AND METALLOGRAPHIC PROPERTIES OF TWO DIFFERENT ALUMINUM ALLOYS JOINED WITH FRICTION STIR WELDING METHOD USING DIFFERENT WELDING PARAMETERS
    (Yildiz Technical Univ, 2020) Ocalir, Seref; Esme, Ugur; Boga, Cem; Kulekci, Mustafa Kemal
    In this study two aluminum alloy materials of EN AW-5083-H111 and EN AW-6082-T651 were joined with Friction Stir Welding considering the parameters as the tool shoulder diameter, spindle speed and feed rate. The mechanical properties of the weld joints such as yield strength, tensile strength and micro-hardness and metallographic properties were investigated comparatively with the use of these welding parameters. The yield strength of the weld joints were determined to be between 136-217 MPa while the tensile strengths were between 159-230 MPa and the percent elongations were between 2.28-5.44 %. The hardness values measured in weld areas were higher in the EN AW-6082 base metal side compared with EN AW-5083 base metal side.
  • [ X ]
    Öğe
    Microstructural and Mechanical Characterization of Dissimilar Metal Welding of Inconel 625 and AISI 316L
    (Mdpi, 2018) Dokme, Fatih; Kulekci, Mustafa Kemal; Esme, Ugur
    This study investigated the microstructure of the dissimilar metal welding of Inconel 625 and AISI 316L using Continuous Current Gas Tungsten Arc Welding (CCGTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) processes with ERNiCr-3, TIG 316L and twisted (ERNiCr-3 and TIG 316L) fillers. Microstructure examinations were carried out using an optical microscope and Scanning Electron Microscopy (SEM)/Energy Dispersive X-Ray (EDAX). The results of the study showed the existence of a partially melted zone (PMZ) on the AISI 316L side. Weld zone (WZ) analysis showed the existence of a multi-directional grain growth on the 316L side in all specimens, although less growth was found on the Inconel 625 side. Grain growth almost disappeared using PCGTAW with twisted fillers. SEM/EDAX investigations indicated that secondary deleterious secondary phases were tiny and white in five experiments. However, a meager amount of precipitates occurred in PCGTA welding with twisted fillers. Moreover, these were particularly innocent precipitates, represented by black dots in images, whereas other tiny white secondary phases are known to be brittle. As a result, PCGTA welding with twisted fillers exhibited the best metallurgical properties.
  • [ X ]
    Öğe
    Multi Response Optimization of Friction Stir Spot Welding Process
    (2021) Er, Onur; Kulekci, Mustafa Kemal; Esme, Ugur; Boğa, Cem
    Friction stir spot welding (FSSW) is a solid state welding method mainly used to join non-ferrous metalsand their alloys. When opposed to other welding processes, FSSW has the benefits of being pollution-freeand having no filler material. In this study an attempt was made for multi response optimization offriction stir spot welded EN AW 5005 aluminum alloy using Taguchi method and Grey relational analysis(GRA). Pin height (h, mm), tool rotation (S, rpm), and welding time (t, s) were used as input parameterswhile tensile shear strength (TSS, MPa) and joint efficiency (JE, %) were used as multi responseparameters. Therefore, Taguchi’s L8 orthogonal design matrix was used in order to plan the experiments.GRA was then applied to determine the optimum condition which gives the higher grey relational degree.Analysis of Variance method (ANOVA) was also carried out in order to show the most significantparameter. Finally, confirmation test was applied to confirm the results and determine the improvement ingrey relational grade throughout this method. The best results were obtained with parameters such as2.6 mm pin height, 1500 rpm tool rotation and 10 s welding time with 122.16 MPa TSS and 111.05 JE. Asignificant improvement of 0.310 was obtained in the optimal parameter in grey relation grade.
  • [ X ]
    Öğe
    Optimization of Friction Stir Welded Dissimilar Aluminum Alloys EN AW-5083-H111 and EN AW-6082-T651 using Hybrid Taguchi-Based Grey Relation Analysis
    (2022) Esme, Ugur; Öcalır, Şeref; Kulekci, Mustafa Kemal
    Friction Stir Welding (FSW) which is a kind of solid state welding process used essentially for joining nonferrous metals and their alloys. Involving pollution free and no filler material are the advantages of FSW when compared to other welding methods. The present work was focused on the multi objective optimization of friction stir welded EN AW-6082-T651 and EN AW-5083-H111 aluminum alloys using Taguchi based Grey relational analysis (GRA) method under different parameters of shoulder diameter (SD, mm), tool rotation (TR, rpm) and welding speed (WS, mm/min) on tensile strength (TS, MPa), percent elongation (E, %) and joint efficiency (JE). Taguchi related experiments were performed using L27 Orthogonal Array. The grey relational analysis which relates between the FSW parameters and the responses applied to find the optimum condition. Additionally, the Analysis of Variance (ANOVA) approach was used to identify the most important factor and its impact on the multiple response. The results of the obtained tests were then verified using the confirmation test.
  • [ X ]
    Öğe
    Optimization of the Effect of Processing Parameters on Surface Roughness and Cutting Energy in CNC Milling of Al-7075 Material
    (2020) Pınarbaşı, Ali Talip; Külekçi, Mustafa Kemal; Esme, Ugur; Boğa, Cem
    In this study, it is intended to determine the most suitable process parameters for surface roughness and cutting energy of the 7075 series aluminum material in dry environment conditions by using Taguchi method in CNC milling. The process parameters were determined as, cutting speed, feed rate and cutting depth and the effects of these parameters on surface roughness, current flow through the grid and the energy consumed were examined. As a result, optimum process parameters were determined and the results were analyzed by graphs. It was observed that the most effective parameter on the surface roughness was the feed rate, while the most effective parameter on the current drawn from the network was the cutting depth. As a result of the experiments, the best surface roughness value was found to be 0.39 μm and the lowest current value was 0.9 A. In addition, considering the determined current amount and processing time, the lowest energy amount consumed was calculated as 7089.28 J.