Browsing by Author "Hocalar, C"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    The Effect of Heat Treatment on The Wear and Corrosion Behavior of AISI 440B Martensitic Stainless Steel in Different Environments
    Saklakoglu, N; Eyici, G; Aslan, N; Hocalar, C; Çimen, O
    This study demonstrates that the austenitization temperature of AISI 440B martensitic stainless steel crucially influences wear and corrosion resistance. As the austenitization temperature increases, Cr23C6 carbides dissolve, leading to increased Cr and C concentrations in the austenite matrix. Higher Cr content enhances corrosion resistance, while increased C content raises hardness. However, excessively high austenitization temperatures result in increased retained austenite due to lowered Mf temperatures and grain coarsening, which significantly reduces hardness. Electrochemical corrosion tests that have been done in wet wipe solution and NaCl solution have shown that a high carbon content can break the martensitic crystal lattice, destabilizing the protective oxide film and reducing corrosion resistance. This study identifies 1110 degrees C as the optimal austenitization temperature for AISI 440B martensitic stainless steel, balancing both wear and corrosion resistance effectively.
  • No Thumbnail Available
    Item
    Experimental evaluation and FE simulation of phase transformations and tensile stresses in hot forging and controlled cooling
    Hocalar, C; Saklakoglu, N; Demirok, S
    This paper encompasses the development of a microstructure-based numerical model (FEM) of the conveyor cooling process after the hot forging of industrial steel with accu-rate predictions of the volume fraction of phases as yield and tensile strengths. An experi-mental procedure for validating the FEM was conducted using optical and scanning electron microscopy and tensile tests. Results showed very good agreement between the phase predic-tions of the 3D FEM model and those obtained from direct measurement of forged parts, with an average error of about 3.6 and 6.9 % for ferrite and pearlite phases, respectively. Tensile test results were evaluated at a 90 % reliability level, and very good agreements were obtained with an error of about 3 and 5 % for the yield and tensile strengths. The methodology could predict the phase transformations, and the mechanical properties during cooling after the hot forging of the steel were investigated.