Effect of Various Types of Chills on Mechanical Properties and Fracture Toughness of Hypoeutectic Cast Iron

Hypo-eutectic cast iron specimens were cast using chills that were sub zero water-cooled, water-cooled and graphite end chills. The solidification behavior, number of eutectic cells, grain size and the effects of these on the mechanical properties like strength and fracture toughness were recorded and analyzed and compared with specimens of the same chemical composition which were sand cast without chill. It is revealed from the above investigation that sub-zero and water cool chilled cast irons exhibit severe under-cooling compared to normal sand cast iron. Thus, it is concluded from the investigation that nucleation conditions are completely altered during solidification but growth conditions prevail as usual. Therefore, under-cooling during solidification is considered to be responsible for the water-cooled variation in eutectic cell size, grain size, and microstructure and hence, the mechanical properties of the cast iron.