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

Abstract

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 = LRG1.5 < Mcritical, 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 Mcritical 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.