Effect of Isothermal Transformation Treatment and Tempering on the Microstructure and Hardness of a Medium C and High Si Steels

This research work aims to study the effect of 2wt%Mo on bainitic transformation kinetics and bainite morphology in 0.6wt%C-1.2wt%Si-1.0wt%Mn-0.2wt%Cr steel. Specimens are austenitized at 950°C rapidly cooled salt bath isothermally treated between 200°C–300°C for different time intervals. Another set specimens oil after an austenitization treatment then tempered temperature range 200°C–550°C. In C–Mn–Si specimens, amount retained austenite increases with increasing but no is observed C–Mn–Si–Mo specimens. The tempering behavior alloy considerably than that Mo free alloy. a martensitic microstructure shows secondary hardening peak upon 500°C. examination would also contribute steels. do not show hardness softening retarded same range.