Computer simulation of shrinkage related defects in metal castings – a review

Simulation of shrinkage related defects in shape castings has been extensively studied because of its potential contribution to quality improvement of cast products. Although the location of macroshrinkage can be estimated rather easily by present solidification models, it is still difficult to quantify its size. In spite of concentrated efforts and numerous claims of success, microporosity prediction is still a subject looking for a solution. After a succinct analysis of the physics of the problem, this paper reviews the various approaches to modelling macro- and micro-porosity evolution, from simple thermal models and criterion functions, to channel and porous medium models based on hydrogen diffusion, and finally to a most recent model based on oxide entrapment.