Thermal analysis of nodular and lamellar eutectic cast iron under different cooling rates
2003 (English)In: International Journal of Cast Metals Research, ISSN 1364-0461, Vol. 16, no 03-jan, 53-58 p.Article in journal (Refereed) Published
Thermal analysis was performed on neareutectic nodular and lamellar cast iron,alloys under different cooling rates. In a DTA setup, cooling rates from 0.08 K/sec to 0.35 K/sec were used, while in a mirror furnace setup cooling rates up to 55 K/sec were reached. At low cooling rates, the solidification behaviour was analyzed by interrupting the process through quenching. The volume fraction of each phase and substructure was evaluated together with the latent heat at different solidification times. It was observed that the growth rate of the nodules decreases with time. Measurements on the number of nodules indicate that the nucleation rate is constant through the solidification process. The measured latent heat of fusion varies along the solidification process for nodular cast iron but not for lamellar cast iron. This difference in the solidification behaviour may be explained by different diffusion kinetic laws. It was also found that the measured latent heat of fusion decreases when the cooling rate increases. Alloys with nodular graphite showed lower latent heat in comparison with the alloys with lamellar graphite at high cooling rates. This effect is explained by means of thermodynamics of lattice defects, such as vacancies, formed in the austenite and graphite phase during solidification.
Place, publisher, year, edition, pages
2003. Vol. 16, no 03-jan, 53-58 p.
eutectic cast iron, thermal analysis, solidification process, alloys
IdentifiersURN: urn:nbn:se:kth:diva-22941ISI: 000186431800011OAI: oai:DiVA.org:kth-22941DiVA: diva2:341639
QC 201005252010-08-102010-08-10Bibliographically approved