Prediction of Hot Tear Defects in Steel Castings Using a Damage Based Model

Caterpillar has been collaborating with suppliers to analyze steel castings for the tendency to form hot tears using a newly developed damage-based model. The implementation and application of the damage-based hot tear model is presented. The implementation is through an uncoupled simulation of the solidification and deformation problems using commercial software with a user-defined constitutive model. However, the liquid feeding and shrinkage porosity information is coupled to the solid deformation constitutive model to calculate the material damage. Hot tears should then initiate at locations where significant damage is predicted. Two industrial case studies are presented that demonstrate the effectiveness of the hot tear model at predicting the locations where hot tears form. Good correlation with indications on castings is observed. Using this new model and collaborating with foundries, part geometry can be modified or casting process changes can be identified before designs are finalized and production begins, reducing the likelihood of hot tear issues occurring.