Microstructure and Mechanical Properties of Medium-Carbon Si-Rich Steel Processed by Austempering after Intercritical Annealing

In the present paper, medium-C Si-rich steel with a quenched martensite microstructure was heated to intercritical annealing temperatures at 750 °C, 760 °C and 770 after warm rolling deformation obtain ferrite varying volume fractions. Subsequently, bainite/ferrite multiphase microstructures were attained via austempering near Ms temperature. The of test different heat treatments characterized by scanning electron microscopy, transmission microscopy backscatter diffraction, corresponding tensile impact properties tested. results showed that, increase temperature, austenite content increased, which limited growth grains, grain size decreased from ~1.6 μm ~1.4 μm. addition, degree recrystallization almost complete. At same compared above Ms, prior athermal (PAM) obtained below effectively refined bainite lath. Moreover, increased austempering, resulting in yield strength, strength energy. contrast, while decrease led significant uniform elongation. constant slightly, property improved Ms.