Thermo-elasto-plastic finite element analysis of warping deformation during casting of gray cast iron

Warpage defect is a crucially important difficulty, especially for large or long iron castings. Thermal stress analysis via computer aided engineering (CAE) is an effective means of predicting warpage defect. Nevertheless, no report of the relevant literature has described a study investigating the mechanism of warping deformation by comparison of in-situ measurements of warpage deformation in an iron casting during cooling with results of thermo-elastic-plastic analysis. This study measured warping deformation of a gray cast iron casting composed of thick and thin parts during sand casting. Then the deformation process was elucidated experimentally. Subsequently, based on the experiment results, this study used thermo-elasto-plastic analysis and simulated warping deformation in iron casting. Then the simulation results were compared with actual measurements, which revealed that the analytically obtained results agreed qualitatively with the experimentally obtained measurements of warping deformation. Results demonstrated that the warping deformation of the casting can be predicted with error of not more than 26%. The temperature difference that existed when the whole casting had haven strength caused different thermal contraction of thick and thin parts during cooling, which produced warping deformation of the iron casting.