G/R^(1/2)法在球铁件缩孔缩松预测中的应用研究

Application of G/R Method to Prediction of Shrinkage Cavity and Porosity in Ductile Iron Castings

浇注了一系列的球墨铸铁件，解剖铸件，测定铸件缩孔体积。对铸件开展了凝固过程三维温度场数值模拟，并应用Ｇ／Ｒ法对铸件进行了缩孔缩松预测。结果表明，空间步长、时间步长、计算Ｇ／Ｒ值的评价温度以及判断缩孔缩松的临界值均影响Ｇ／Ｒ值，从而影响缩孔缩松预测的准确程度，Ｇ／Ｒ法不适用于球墨铸铁件缩孔缩松的预测。

Abstract A series of ductile iron sample castings were poured and dissected to determine the volume of shrinkage cavity of sample castings.The numerical simulation of 3D temperature field of castings during solidification process was carried out and the shrinkage cavity and porosity of sample castings were predicted using G/R method.The results showed that the G/R value are influenced by space increment,time increment,evaluation temperature of the computed G/R value and the critical value of predicting shrinkage cavity and porosity in castings,thus impairing the accuracy of its prediction.G/R method is not suitable for the prediction of shrinkage cavity and porosity of ductile iron castings.