Effect of Microsegregation and Bainitic Reaction Temperature on the Microstructure and Mechanical Properties of a High-Carbon and High-Silicon Cast Steel

Bainitic microstructures obtained in high-carbon (HC) and high-silicon (HSi) steels are currently of great interest. Microstructural evolution the bainitic transformation kinetics a cast steel held at 280, 330, 380 °C was analyzed using dilatometry, X-ray diffraction, optical scanning electron microscopy, backscatter diffraction (EBSD). It is shown that heterogeneous distribution silicon (Si), manganese (Mn), chromium (Cr) associated to microsegregation during casting has impact on final microstructure. The starts dendritic zones where there lower Mn concentration then expands interdendritic ones. As reduces carbon activity, areas with higher enriched (C), thus, these contain greater amount retained austenite plus martensite, resulting Higher temperatures promote amounts residual poor thermal/mechanical stability presence martensite microstructure, which detrimental effect mechanical properties. Tensile tests revealed ultra-fine microstructure developed by 280 promotes very high values both tensile yield stress (?1.8 GPa 1.6 GPa, respectively), but limited ductility (?2%).