A Simplified Hot-Tearing Criterion for Shape Castings Based on Temperature-Field Simulation

Current hot-tearing predictions for shape castings are suitable for well-investigated alloys with complete mechanical property databases, but are not applicable to newly developed alloys. This study proposed a simplified hot-tearing criterion for shape casting based on the hot-tearing sensitivity to strain rate during solidification. The criterion is simplified to a specific form: M = LRG^1.5 < M_critical, based on the constrained rod casting method that is used to evaluate the hot-tearing susceptibility of Mg alloys, where L (length of the constrained rod), R (the cooling rate), and G (the temperature gradient) can be calculated by numerical simulation, while M_critical can be determined by comparison of simulation and experimental results in the constrained rod casting. The prediction of the hot-tearing criterion for a 14-inch (0.35 m) Mg wheel casting was in good agreement with the experimental results, confirming its practicability. The proposed hot-tearing criterion is suitable for newly developed alloys without need of consideration of their mechanical properties.