It is known that hot tearing tendency increases with the increase in the cooling rate of casting during solidification. As the direct control factors of hot tearing, the cooling rate dependences of the temperature field of the casting and mechanical properties of alloys in the semi-solid state have been suggested. However, quantitative evaluation has yet to be carried out to clarify which parameters are more important for predicting hot tearing tendency.
In this study, through thermal stress analysis using the cooling rate-dependent temperature fields of casting and cooling rate-dependent creep parameters in the semi-solid state, hot tearing tendency was predicted for an Al-Mg alloy during solidification. For the prediction, the maximum principal creep strain accumulated during the solidification was used as an indicator of hot tearing tendencies. Then, the hot tearing tendencies were compared with experimental results. As a result, in the cooling rate range of this study which corresponded to gravity die casting, it was found that temperature fields are relatively more critical for predicting hot tearing tendency than the creep parameters.
