Influence of Austempering Processing on Microstructure and Mechanical Property of Austeniticbainitic Cast Steel

Influence of austempering heat treatment parameters (homogenized temperature, austempering temperature, austempering time, etc.) on the microstructure and mechanical properties of cast steel was studied systemically. The results showed that austeniticbainitic structure with freecarbide could be obtained in a designed high carbon (075%) and high silicon (24%) cast steel by proper austempering processing range from 280℃ to 360℃, with the rise of austempering temperature, the bainite morphology changed from needle lower bainite to feather upper bainite. The results also showed that the influence of austempering processing on mechanical property was intricate, an optimal combination of mechanical properties could be achieved with homogenized temperature and time at 900℃×120min and austempering temperature and time at 320℃×120min.