Research Initiation: Application of Thermal Analysis to Numerical Simulation of Solidification and Shrinkage Prediction in Ductile Iron Castings

该项目致力于开发用于预测近共晶和近共晶商业球墨铸铁件缩松缺陷的有限元凝固模拟软件。要实现这一目标，必须解决两个根本性问题。首先，共晶合金的凝固过程本质上是在恒温条件下发生的，其凝固过程比冻结区间合金的凝固过程更难模拟，这是因为在焓-温度关系中存在不连续性。其次，球墨铸铁的凝固行为可能是常见铸造合金中最复杂的，它对冶金工艺条件极其敏感，因此根本不适合根据基本考虑进行建模。这两个问题可以通过一种新的应用冷却曲线数据的牛顿分析来克服，以获得直接解释冶金加工实践中给定合金独特的凝固特征的热产生函数，该函数可以有效地并入有限元凝固模拟程序，以逼真地模拟凝固过程中的潜热释放。这项工作预计将对整个铸造行业产生重大影响，并首次在基于数值模拟的计算机辅助设计和基于热分析的铸造过程控制之间建立了直接联系。

The project deals with the development of finite element solidification simulation software for the prediction of shrinkage defects in near and near-eutectic commercial ductile iron castings. In order to accomplish this goal, two fundamental problems must be solved. First, the solidification of eutectic alloys which occurs essentially at constant temperature is inherently more difficult to simulate than that of freezing range alloys because of the discontinuity in the enthalpy-temperature relationship. Secondly, the solidification behavior of ductile iron, perhaps the most complex of the common casting alloys, is extremely sensitive to metallurgical processing conditions and hence not at all amenable to modeling on the basis of fundamental considerations. It is proposed that both problems may be overcome by a novel application of Newtonian analysis of cooling curve data to obtain a heat generation function that directly accounts for unique solidification characteristics of a given alloy attributable to metallurgical processing practice which can be efficiently incorporated into finite element solidification simulation code to realistically model the liberation of latent heat during solidification. A significant impact on the foundry industry as a whole is anticipated from this work, and for the first time provides a direct link between computer-aided design based on numerical simulation and process control in the foundry based on thermal analysis.