Simulation of Shrinkage Porosity Formation During Alloy Solidification
Simulation of Shrinkage Porosity Formation During Alloy Solidification
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DOI：
10.1007/s11661-020-05699-z
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发表时间：
2020-03-10
影响因子：
2.8
通讯作者：
Beckermann, Christoph
中科院分区：
文献类型：
--
作者：
Khalajzadeh, Vahid;Beckermann, Christoph
由凝固收缩引起的缩松是金属铸造中的一大难题。这会导致低成品率和增加生产成本，并限制在役铸件的性能。通过在铸造过程模拟中可靠地预测气孔，可以最大限度地减少或消除气孔。本文提出了一种新的模拟凝固过程中缩松形成的模型。该模型是基于最近的一项发现，即缩松在铸件固相分数最低的区域形核和长大。在考虑冷却和凝固过程中密度变化的同时，计算了液体中的进料流量和压力分布。它预测铸件中所有类型缩松的位置、程度和数量，包括冒口管道和大内孔、表面下沉和分布的微缩孔。对于简单的铸件几何形状和较复杂的锰钢实验铸件，给出了孔隙率预测。与实验铸件中的观察结果的比较表明，该模型能够准确预测各种类型的缩松。数值研究考察了预报对不同模型参数的敏感性。
Porosity due to solidification shrinkage is a troublesome defect in metal casting. It results in low yields and increased costs in production and limits the performance of cast components in service. By reliably predicting porosity in casting process simulation, porosity can be minimized or eliminated. Here, a new model for simulating the formation of shrinkage porosity during solidification is presented. The model is based on the recent discovery that shrinkage porosity nucleates and grows in regions of a casting where the solid fraction is the lowest. It calculates the feeding flows and pressure distribution in the liquid while accounting for the density variation during cooling and solidification. It predicts the location, extent and amount of all types of shrinkage porosity in a casting, including riser pipes and large internal holes, surface sinks, and distributed micro-shrinkage. Porosity predictions are presented for simple casting geometries and for a more complex Mn-steel experimental casting. The comparisons to the observations made in the experimental casting demonstrate the capability of the model to accurately predict the various types of shrinkage porosity. Numerical studies are performed to investigate the sensitivity of the predictions to various model parameters.