Eutectic cell and nodule count in grey and nodular cast irons

Abstract

In the present work the predictions of a proposed analytical theory were compared with the experimental outcome on metallographic determinations of eutectic cell count N and nodule count Nn. Accordingly, processing of flake graphite and ductile cast irons was carried out under various inoculation conditions in order to achieve a range of physicochemical states for the experimental melts. In addition, plates of various wall thicknesses s were cast and the resultant eutectic cell and nodule counts were established. Moreover, thermal analysis was employed for determinations of the maximum degree of undercooling for the graphite eutectic ΔTm. A relationship was found between the eutectic cell N or the nodule count and ΔTm. In addition, it was found that N and Nn can be related to the casting modulus M and hence to s in plate shaped castings. Finally, the present work provides insights into the effect of technological factors such as the melt chemistry, the inoculation practice and the holding temperature and time on the resultant N and Nn values. In general, it was found that the predictions of the present analysis are in good agreement with the experimental outcome.