Browsing by Author "Kurt, Bulent"
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Item Influence Ferrite Grain Size on the Development of Discontinuons Flow at Lowcarbon Steel(Nevsehir University, Turkey, 2021) Vakulenko, Igor A.; Kurt, Bulent; Erdogdu, Ahmet Emrah; Asgarov, KhangardashENG: On example of low-carbon steel, it is shown that development of strain hardening processes, starting from the moment initiation of plastic deformation, determines nature behavior of the metal at all subsequent stages of loading. The conditions formation of deformation bands and reasons for the disappearance of intermittent yield section on the deformation curves are considered. The use of the dependence characteristics of strain hardening on the size ferrite grain made it possible to explain evolution structure of low-carbon steel at region of intermittent flow.Item Influence of Plastic Deformation Carbon Steel on the Process of Burning lectric ARC(Silesian University of Technology, Poland, 2021) Vakulenko, Igor A.; Plitchenko, Sergey; Kurt, Bulent; Askerov, Hangardas; Proydak, Svetlana V.; Erdogdu, Ahmet EmrahEN: 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%.Item Influence Structure on the Plasticity of Carbon Steel of the Railway Wheel Rim in Operation(Silesian University of Technology, Poland, 2022) Vakulenko, Igor A.; Vakulenko, Leonid I.; Bolotova, Dariy M.; Kurt, Bulent; Asgarov, Hangardash; Çölova, ÖmerENG: Summary. When simulating the operating conditions of the rim of a railway wheel, an analysis of change in the structural state from the possible degree of plastic deformation and the heating temperature of steel near the rolling surface was carried out. The development processes of spheroidization and coalescence of cementite during heating of the cold-worked steel change its ability to strain hardening. Substructure changes during heating to temperatures of 500-550°C deformed steel are accompanied by a simultaneous decrease in its ability to strain hardening and the level of plasticity. When heated above 500-550°C, the development of ferrite recrystallization processes provides a gradual transition of the metal from substructure hardening to hardening from grain boundaries with large angles of disorientation. It is shown that regardless of the nature of the main structural element, the ability of steel to strain hardening and the level of plasticity after heating are related by a proportional relationship.Item Structural Changes at Metal of a Railway Wheel Along Rolling Surface(Nevsehir University, Turkey, 2021) Vakulenko, Igor A.; Kurt, Bulent; Bolotova, Daria M.; Colova, O.ENG: As a result rolling of the hardened carbon steel without slipping, only due to normal loading, a decrease in hardness is observed. The observed decrease in hardness is due to the development of softening processes during plastic deformation. Additional slippage at the contact points of the samples accelerates development of softening effects in the hardened metal. It has been found that softening during rolling of a quenched metal is accompanied by a refinement of the coherent scattering regions, increase in internal stresses, and increase at number of crystal structure defects.Item Structural Transformation at Friction Stir Welding of Aluminum Alloy(Nevşehir Hacı Bektaş Veli Üniversitesi, 2020) Vakulenko, Ihor O.; Plitchenko, Serhii; Kurt, BulentEN: On example of aluminum alloy AMg6 the questions concerning development processes of structure formation during friction stir welding are considered. From analysis changes in technological parameters of welding process, a qualitatively different nature of the temperature change is determined when approaching conditions of the super plastic deformation. In accordance with determined heating temperatures, effect grain size of solid solution on hardness in micro volumes of the alloy after forming weld joint was analyzed. From analysis dependence of micro hardness on grain size, it is determined that as the temperature increases, contribution to achieving conditions of super plastic flow from the grain boundaries with large angles of disorientation increases, and effect from solid solution state are decreases.Item Transformation of Structure During Friction Stir Welding(Silesian University of Technology, Poland, 2021) Vakulenko, Igor A.; Plitchenko, Sergey; Kurt, Bulent; Proydak, Svetlana V.; Askerov, HangardasEN: 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.Item Сauses of Structural Heterogeneity Low-Carbon Sheet Steel and its Elimination(Nevsehir Hacı Bektaş Veli University, Kızılcahamam, Ankara, Turkey, 2019) Askerov, Khangardas; Cug, Harun; Kurt, Bulent; Vakulenko, Ihor A.; Proydak, Svetlana V.EN: Abstract. Based on the analysis of mechanism development of ferrite recrystallization processes, on example of lowcarbon hot-rolled sheet steel, measures are proposed reduce heterogeneity of structure rolled products. Creating a certain gradient in distribution defects of crystalline structure over the thickness of sheet lowcarbon steel allows after annealing