Investigation into the Microstructure and Mechanical Properties of Thin Wall Austempered Gray Cast Iron (TWAGI)

The main aim of this investigation is to assess the mechanical properties of thin wall (3 mm thickness) copper alloyed gray cast iron. Thin wall alloyed gray cast iron specimens are subjected to austempering heat treatment at six different temperatures for four different time periods. As a result, these samples develop an ausferrite matrix with excellent mechanical properties. The resulting microstructures have been evaluated and characterized by means of optical microscope and scanning electron microscope (SEM) and X-Ray diffraction analysis. The hardness and tensile properties of all these specimens are determined and correlated with the microstructure. The hardness, tensile strength and ductility initially increase, and thereafter it decreases on longer periods of austempering. On the other hand, hardness and tensile strength decreases with increasing austempering temperature, while ductility increases.