Influence of Austempering Temperature on Microstructure and Mechanical Properties of Cast Fe-Si-Mn-VSteel

The present investigation was carried out to examine the
influence of austempering temperature on the micro-structure and mechanical properties of a low carbon, high silicon (C-0.13%, Si-1.2%, Mn-1%, V-0.08%) cast steels. The Induction melted casting block was homogenized at 1000°C for 6 hrs. The samples for microstructure and the tens-ile specimens were prepared from the cast steel block according to ASTM standards and were imparted three diff-erent austempering heat treatments to produce different microstructure. The samples are austenitisation at 900°C for 30 minute and then rapidly quenched to a salt bath maintained at temperature 350/400/450°C for 10 minute and then finally air cooled. The microstructure were observed under optical and TEM microscopy. show that UTS decreases
but % El increases with increasing apstempering tempe-rature. The 400°C austempering temperature exhibited the best combination of UTS and %EI at room temperature (UTS-663 MPa, EL-26%) with revealing microstructure of bainite and retained austenite.