NUMERICAL MODELLING OF AUSTENITE-FERRITE TRANSFORMATION IN ADI

1 OLEJARCZYK-WOŻEŃSKA Izabela
Co-authors:
1 ADRIAN Henryk 1 MRZYGŁÓD Barbara 1 GŁOWACKI Mirosław
Institution:
1 AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, al. A. Mickiewicza 30, 30-059 Cracow, iolejarc@agh.edu.pl
Conference:
24th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, June 3rd - 5th 2015
Proceedings:
Proceedings 24th International Conference on Metallurgy and Materials
Pages:
810-815
ISBN:
978-80-87294-58-1
ISSN:
2694-9296
Published:
12th January 2015
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
44 views / 10 downloads
Abstract

The heat treatment process of ductile iron involves two stages: austenitising at temperatures in the range of 850-950oC with the following austempering of alloy in the temperature range of 250-380oC. The resulting microstructure contains ferrite saturated with carbon in a matrix of reacted high-carbon austenite with spheroidal graphite typical of ductile iron. This microstructure confers high mechanical properties to the alloy. The microstructure and mechanical properties of ADI depend on the kinetics of phase transformations during austempering.The kinetic model of phase transformations occurring during austempering of undercooled austenite in ADI was developed. The model is based on Fick’s diffusion laws. The differential equations were solved by the Finite Difference Method (explicit scheme) under the boundary conditions adequate for the austempering temperature. In calculations, the effect of carbon content in austenite on its diffusion coefficient was considered. The developed model and computer program enabled tracing the process of ausferrite growth. Using the developed computer program, the effect of isothermal annealing temperature on the growth rate of ferritic phase was investigated.

Keywords: Austempering, ADI, modelling of phase transformations

© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Scroll to Top