Modeling of microstructure and residual stress in cast iron calendar rolls
A comprehensive mathematical model based on the commercial finite-element (FE) code ABAQUS has been developed to predict the evolution of temperature, microstructure, and residual stresses in cast iron castings. The thermal component of the model, applied in stage one of the analysis, is capable of simulating the formation of microstructure over a broad range of cooling conditions, including the formation of columnar white iron as well as equiaxed gray iron. To test the model, it has been evaluated against thermocouple and microstructural data collected from a reduced-scale calendar roll test casting. The model has been demonstrated to be able to predict the transition from columnar white iron to equiaxed gray iron which occurs approximately 20 mm below the outside surface of the roll test casting. In addition, the model is shown to be able to satisfactorily reproduce the evolution of temperature recorded from thermocouples embedded at various locations in the test casting. An elastic-plastic stress analysis, applied in the second stage of the analysis, was performed using the temperature history and the volume fraction of white and gray iron obtained with the thermal/microstructural model. The results were verified against residual stress measurements made at various locations along the outer-diameter (OD) surface of the roll. The elastic-plastic model accounts for the temperature-dependent plastic behavior of white and gray iron and the thermal dilatational behavior of white and gray iron, including volumetric expansion due to austenite decomposition and dilatational anisotropy in columnar white iron. The results of the mathematical analysis demonstrate that the residual stress distribution in full-scale calendar thermorolls cannot be deduced simply from knowledge of the microstructural distribution and basic dilatometric considerations, as is currently the practice in industry.
- Research Organization:
- Univ. of British Columbia, Vancouver, British Columbia (CA)
- OSTI ID:
- 20050552
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 31, Issue 4; Other Information: PBD: Apr 2000; ISSN 1073-5623
- Country of Publication:
- United States
- Language:
- English
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