Relationship between specific volume, chemical composition, and fraction of austenite, graphite and cementite during eutectic reaction of cast iron

A method for calculating the specific volume of austenite is presented in which the influence of chemical composition on the lattice parameter of austenite is considered. The specific volume of cementite is also calculated by the same method. Based on the principle of mass conservation, the relationship between specifc volume, composition and the fraction of austenite, graphite and cementite in cast iron during the eutectic transformation has been deduced as follows: spv iron = spv cem. f cem. (1 − g) + spv γ (f γ + f cem. g(0.9332 + C as /100)) + spv Gr f cem. g(0.0668-C as /100). The calculational results predict that the amount of silicon dissolved in austenite affects the specific volume of austenite and cast iron significantly. In addition, the fraction of the different phases in the microstructure exerts an considerable influence on the spv of cast iron. The calculation result has been compared with the published experimental results