Model for the solid state phase transformation and transformation plasticity during casting in grey cast iron GJL350

Abstract

The development of stresses and distortions in solidifying metallic components during casting processes is not only influenced by the temperature field created across the mould but can also be strongly influenced by the transformation kinetics occurring in the solidifying metal. It is challenging to apply numerical methods which are strictly based on a coupled thermo-mechanical model because the models do not account for the inhomogeneous distribution of alloying elements, particularly carbon. Therefore a viable model has to take into account some preselected difference by heated states using short-time austenitizing, which includes a carbon gradient in order to understand the influence of carbon on thermomechanical properties. The aim of the present work is to identify high temperature parameters for a lamellar cast iron GJL-350 in order to include them into a material model. The transformation kinetics for non-isothermal transformations are determined from measured isothermal TTT-diagrams at differently heated states. Doing so, it was also possible to determine the isothermal TTT-diagrams as a function of the carbon content in the matrix. © 2010 IOP Publishing Ltd.