Influence of austempering temperature on microstructure and fracture toughness of a high-carbon, high-silicon and high-manganese cast steel

An investigation was carried out to examine the influence of austempering temperature on the microstructure and mechanical properties of a high-carbon (1.00%), high-silicon (3.00%) and high-manganese (2.00%) cast steel. Cylindrical tensile specimens and compact tension specimens were prepared from this cast steel according to ASTM standards and were given four different austempering heat treatments to produce different microstructures. The tensile properties and fracture toughness of these materials were studied at room temperature in ambient atmosphere. Test results indicate that maximum fracture toughness is obtained in this steel when the microstructure contains very high austenitic carbon (XγCγ).