Title: Development and evaluation of a model for solid-state phase transformations during casting of ductile cast iron

Authors: Vincent Runser, Volker Schulze

Addresses: Department of Production and Component Behaviour, Institute of Material Science and Engineering I, University of Karlsruhe, Kaiserstrasse 12, 76131 Karlsruhe, Germany. ' Section Manufacturing Technology, Institute of Production Science (WBK); Institute of Material Science and Engineering I (IWK1), University of Karlsruhe, Kaiserstrasse 12, 76131 Karlsruhe, Germany

Abstract: Casting processes lead to complex states of residual stresses and distortions which are affected by constraints due to the moulds, heat flow and cooling conditions and microstructural evolution. This is especially pronounced in cast irons during cooling in the solid state. The prediction of residual stresses and distortions in the simulation of casting processes can only be successful if these phase transformations are fully described. The experimental determination of the kinetics of these phase transformations is a very challenging task because the casting process is severely transient and therefore the material state before the solid state transformation cannot be received by heating again. In this paper a model is developed for ductile cast iron GJS-600, which describes the phase transformations from an austenite-graphite state considering the inhomogeneity of the initial austenite. The paper deals with the model, the experimental procedure for the needed short time dilatometry and with the experimental results and their discussion.

Keywords: solid state phase transformation; short time austenitisation; ductile cast iron; casting; residual stress; kinetics; modelling; austenite; dilatometry; distortion.

DOI: 10.1504/IJMMP.2010.037614

International Journal of Microstructure and Materials Properties, 2010 Vol.5 No.4/5, pp.375 - 385

Published online: 20 Dec 2010 *

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