Phase Transformations of 5Cr-0.5Mo-0.1C Steel after Heat Treatment and Isothermal Exposure

This study consists of the experimental and numerical analysis phase transformations 5Cr-0.5Mo.0.1C steel after heat treatment. The microstructure as-received comprised ferrite bainite, which is in agreement with microconstituents predicted by Calphad-calculated TTT diagram. Calphad-based precipitation calculations show that cooling stage normalizing treatment did not cause carbide formation. In contrast, tempering at 700 °C for 15 min promotes intergranular Fe3C, M7C3 M23C6 carbides, consistent results. Aging 600 short periods caused both carbides; however, dominant prolonged aging. A rapid decrease hardness was observed aging, attributable to bainite transformation. Further reduction associated diffusion-controlled coarsening carbide.