Yazar "Askerov, Hangardas" seçeneğine göre listele

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    THE CALCULATION OF STRESS INTENSITY FACTOR STEEL OF RAILWAY WHEELS
    (Fac Transport Silesian Univ Technology, 2020) Vakulenko, Igor; Proydak, Svetlana; Askerov, Hangardas
    From an analysis of the dependence complex of carbon steel properties on structural parameters, it was found that for an isostructural state, the influence of austenite grain size on impact strength exceeds the dependence on carbon content. As a result of explaining correlation relationships between individual mechanical characteristics, to evaluate critical stress intensity factor, a relationship is proposed based on the use of impact strength. The proportionality coefficient in proposed dependence is determined by ratio of elongation to narrowing at tensile test.
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    Effect of high temperature oxidation on Inconel 718 and Inconel 718/YSZ/Gd2Zr2O7
    (Iop Publishing Ltd, 2019) Doleker, Kadir Mert; Odabas, Okan; Ozgurluk, Yasin; Askerov, Hangardas; Karaoglanli, Abdullah Cahit
    Oxidation is an important phenomenon for materials used at high temperatures. Generally, nickel based superalloys are preferred as metallic materials due to their superior mechanical properties for high temperature applications. Inconel 718 has wide usage fields in high temperature applications. In present study, Inconel 718 and Inconel 718/Yttria (%8 Y2O3) Stabilized Zirconia (YSZ)/ Gd2Zr2O7 (GZ) was oxidized in open air atmosphere at 1000 degrees C for 8, 24 and 100 h. Isothermally oxidized samples were investigated using Scanning Electron Microscopy (SEM), x-ray Diffraction (XRD) and energy dispersive x-ray spectrometry (EDX)-SEM. Results show that Inconel 718 is not suitable for long periods at 1000 degrees C. Ceramic coated Inconel 718 exhibit better performance and it assist to see phase distributions in microstructure.
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    INFLUENCE OF PLASTIC DEFORMATION CARBON STEEL ON THE PROCESS OF BURNING ELECTRIC ARC
    (Fac Transport Silesian Univ Technology, 2021) Vakulenko, Igor Alex; Plitchenko, Sergey; Kurt, Bulent; Askerov, Hangardas; Proydak, Svetlana; Erdogdu, Ahmet Emrah
    During a study of the combustion process of a direct polarity electric arc, a directly proportional dependence of the electric current value on the degree of cold plastic deformation of carbon steel used as an electrode was found. To calculate the value of the electric current during arc burning, in the indicated ratio, it was proposed to replace the surface tension force of the liquid metal with the surface tension of ferrite of plastically deformed carbon steel. Calculation of the ferrite's surface tension value on the deformation degree of the steel under study through the size of the coherent scattering regions was used to explain the observed dependence of the electric current during arc burning. From the analysis of the considered correlation ratios, it was found that with an increase in the cold deformation degree, the refinement of the coherent scattering regions results in the ferrite's surface tension increase and consequently, to an increase in the electric current during arc burning. Comparative analysis of the obtained results of calculating the value of electric current during arc burning through the surface tension of ferrite of cold-deformed carbon steel showed a fairly good coincidence with experimental data. The differences did not exceed 9%.
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    INSIGHTS INTO FACTORS OF DAMAGE OF SURFACE ROLLING OF RAILWAY WHEELS DURING OPERATION
    (Fac Transport Silesian Univ Technology, 2019) Askerov, Hangardas; Vakulenko, Igor; Grischenko, Nikolaji
    The systematization results of microstructure studies of carbon steel has made it possible to explain the mechanism of formation of certain damages to the rolling surface of railway wheels during operation. The evaluation ability of metal to strain hardening was used to explain the nature of the influence compactly located non-deformable dispersed particles on the strength properties steel during cold plastic deformation. In the process of the interaction of a railway wheel with a rail, successively occurring heterogeneities in the distribution of the plastic flow metal are one of the main reasons for the formation of defects on the rolling surface of the wheel.
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    TRANSFORMATION OF STRUCTURE DURING FRICTION STIR WELDING
    (Fac Transport Silesian Univ Technology, 2021) Vakulenko, Igor Alex; Plitchenko, Sergey; Kurt, Bulent; Proydak, Svetlana; Askerov, Hangardas
    In comparison with low carbon steels, there is increased interest in the use of aluminium-based alloys as materials for the manufacture of welded structures rolling stock of railway transport. During friction stir welding aluminium-based alloy, against the background of the analysis structural transformations, issues of development hardening processes are considered. Under conditions of existence, a temperature gradient at zone of weld formation, shown degree approximation alloy to the conditions of superplastic flow and influence from presence particles of the second phase on grain size of matrix is estimated. Evaluation of the separate influence grain size of matrix and state of solid solution at total hardness of the weld showed dependence of their contributions on temperature of hot plastic deformation. As the temperature of plastic deformation of alloy at area of the weld increases, contribution to the total hardness from grain size increase and on state of the solid solution decreases.