A MODEL FOR THE GRAPHITE FORMATION IN DUCTILE CAST-IRON .2. SOLID-STATE TRANSFORMATION REACTIONS

In the present investigation, mathematical models have been developed to quantify the extent of carbon diffusion occurring in ductile cast i ron during cooling from the eutectic temperature. Computer calculation s show that small variations in the cooling conditions may significant ly alter the number density and size distribution of graphite nodules in the iron matrix, in agreement with experimental observations. This makes it difficult to compare microstructure data from various section size materials without allowing for differences in the kinetic streng th of the thermal cycles with respect to carbon diffusion.