Numerical Simulation of Hot Tears Initiation and Growth in Castings

Abstract

Hot tearing is a common defect encountered with casting process. Current experimental means can only analyze the final hot tearing morphology of castings, and the initiation and growth of hot tears are difficult to observe. In order to predict the initiation and propagation of hot tears, the thermo-mechanical simulation of casting process was conducted by using a thermal elastoplastic finite element model. A new prediction method of hot tearing based on isothermal strain on high temperature was proposed, and the tearing initiation location of the casting was determined. Based on the results of thermal stress field of the casting, the growth of the hot tearing was simulated by the extended finite element method (XFEM) combined with the adaptively refined meshing and sub-model technology. The simulation results show that hot tears tend to occur at the isolated liquid boundary of the casting, and propagate along the solid-liquid interface. The predicted tearing is consistent with the hot tearing observed in the actual casting, both in terms of location and morphology, which proves the reliability of the numerical simulation of hot tears initiation and propagation.