Results and Discussions
3.1 As-cast state The typical as-cast microstructures of test specimens with three C contents are respectively shown in Fig. 2. All specimens show hypoeutectic structure consisting of austenite dendrite and eutectic. The eutectic carbides are mainly granular or string-like MC and plate-like or lamellar M2C that appears at the boundary region of austenite dendrite. The amount of eutectic carbide increases with increasing C content. Matrix of all specimens is mostly austenite with small amount of martensite.