Mathematical models have been developed for the purpose of predicting the evolution of microstructure and residual stress that develops during the manufacture of hypo-eutectic cast iron rolls for the paper industry. These include, a finite element based heat flow model to predict the evolution of temperature and microstructure, and a preliminary finite element based stress model to estimate the evolution of residual stress. Both models have been implemented in the commercial finite element code ABAQUS.

To characterize the evolution of solidified microstructure, specialized routines, employing relationships describing nucleation and growth of equiaxed primary austenite, gray iron and white iron, were formulated and incorporated into an ABAQUS thermal model through user-defined subroutines. These relationships have been adapted and extended from a number of investigations describing equiaxed cast iron solidification presented in the literature. In addition, a preliminary columnar growth model was also implemented and tested to describe white iron growth.

To describe the evolution of residual stress, a preliminary thermal stress model was developed to describe the evolution of stress and strain throughout the casting process. The preliminary stress model utilizes the temperature and microstructure predictions of the thermal model as input and incorporates phase and temperature dependent properties describing the elastic modulus, thermal dilatation, as well as, the strain rate independent, Von Mises, plastic deformation of the various phases.

In order to validate the various components of the overall model, a series of measurements involving two industrial castings - a Quik-cup casting and a reduced scale roll casting - were undertaken to provide thermal, microstructural, and residual stress data for use in 'fine-tuning' and validating the mathematical models. Comparison of the predicted and measured temperatures show good overall agreement for both casting geometries. Microstructure predictions for the Quik-cup casting agree with the observed microstructure. However, in the reduced scale roll casting, key microstructure phenomena were inaccurately predicted with the equiaxed microstructure model. Improvements in the microstructure predictions were observed after the white iron columnar growth model was implemented. Residual stress predictions for the reduced scale roll casting show good overall agreement with the OD surface measurements. The results of this analysis show the importance and usefulness of developing the ability to predict residual stress and microstructure evolution in cast iron rolls.