Browsing by Author "Akkaş M."

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    Computer aided design, analysis and manufacturing of hot rolled bulb flat steel profiles; [Sıcak haddelenmiş çelik hollanda profillerinin bilgisayar destekli tasarımı, analizi ve imalatı]
    (TUBITAK, 2020) Akkaş M.; Onder B.; Sevgi E.; Çulha O.
    In this study, roll-pass designs were designed and controlled rolling simulations were realized by using of Simufact Forming simulation tool based on finite element method for acquiring an asymmetrical profile with low carbon-micro alloyed steel used in ship buildings. Simulation aided manufacturing studies have been realized for eliminating the manufacturing defects and obtaining stress-strain curves, forces acting on the rollers and torque requirements at the inlets and the outlets of the rolling stands. Optimization studies of the production parameters to improve the final product mechanical properties. Mechanical tests and metallurgical tests have been applied to the production samples obtained by ensuring that the production parameters obtained in simulated support activities are used in prototype productions and the improvement of the mechanical properties of the profile with asymmetric section is provided. © 2020, TUBITAK. All rights reserved.
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    An investigation on the reasons of emerging iron oxides in different colors than normal in alloyed steel profiles produced by hot rolling; [Sıcak haddeleme ile üretilen alaşımlı çelik profillerde normalden farklı renkte oluşan demir oksitlerin ortaya çıkış sebeplerinin incelenmesi]
    (TUBITAK, 2020) Akkaş M.; Çulha O.
    The red scale formation in hot rolled steel profiles is a chemical iron oxide reaction that disrupts the natural color of the surface of the steel. Tempering temperature, atmosphere, time and rolling temperature, silicon content in the chemical composition of the raw material affect this formation. In this study, red scale formation on the surface, which is a very rare case in steel profiles produced by hot rolling method, was investigated. Samples were taken from a production which appeared in the forms I and U in the produced profile types. The profiles in which red scale formation is observed are as follows; visual inspection, spectral analysis, XRD analysis and microstructure analysis. According to the findings of the analysis and literature, it was found that the red scale formed in this case has no correlation with the ratio of silicon element. It has been found that the red scale formation of different density in I and U profiles depends on the accumulation of water depending on the rolling position of the profile during rolling. In general, it has been found that hematite scales cause red scales due to cooling effect. © 2020, TUBITAK. All rights reserved.