Mechanical Properties of Austempered Fe-2.0wt.%Si-0.3wt.%Mn Steel with various Carbon Contents

Abstract

In this study, we investigated the effect of carbon on mechanical properties with different austempering conditions of high car-bon(0.7~1.3wt.%C)-2.0wt.%Si steels. The specimens were austenitized at 850, 925 and 1020 o C, and austempered at 260, 320 and 380 o C for the various period of time from 3 min to 300 min. After heat treatment, the evolution of stage I and stage II was iden-tified with optical microscope, XRD and hardness test. When the austempering temperature was 260 o C, the microstructure consisted of the lower ausferrite while the upper ausferrite micro-structure was formed at 380 o C. As the austempering temperature increases from 260 to 380 o C, the tensile strength decreases and elongation increases. In addition, when carbon content increases, tensile strength and elongation decrease.