Effect of austempering variables on the mechanical properties of spheroidal graphite Iron

Austempering variables such as time and temperature have been taken in to consideration for the present investigation with respect to tensile properties and characterization of graphite morphology. Two types of spheroidal graphite (SG) cast iron samples with different weight percentage of copper were austempered at four different temperatures. The austempering temperatures were 250˚C, 300˚C, 350˚C and 400˚C.The influence of austempering process on the mechanical properties of spheroidal graphite iron was investigated as a function of austempering time and temperature. The cooling rate and the quenching technique adopted play an important role for the property development of spheroidal graphite iron. The tensile properties have been correlated with the graphite morphology for both the grades of ADI. SEM micrographs have been taken from the fractured surface of the tensile specimens under different austempering conditions. It has been found from the result that ADI having the alloying element (Cu), achieved significant mechanical properties as compared to other grade (M1) throughout the different austempering process adopted in this study.