球铁磨球凝固过程温度场的数值模拟

Numerical Simulation of Temperature Field in Ductile Iron Grinding Ball during Solidification Process

针对120mm球墨铸铁磨球的金属型铸造工艺,采用有限差分的方法,利用自主开发的模拟软件对磨球的凝固过程进行了温度场的数值模拟,预测了铸件在铸造中可能产生的缺陷位置,并对磨球内部产生缩孔的原因进行了分析。通过增加砂套,缩短内浇道,减小直浇道尺寸等对浇注系统进行了修改和优化,并对优化后的浇注系统进行了温度场的数值模拟。结果表明,优化后的浇注系统实现了顺序凝固,缩孔缺陷从磨球内部转移到了直浇道内,模拟结果与实际浇注结果相符合。

Based on the finite differential method, the temperature field in the solidification process of ductile iron grinding ball in permanent mold was simulated by employing self-developed simulation soft- ware. The possible defect position in the grinding ball was forecasted. The origination of shrinkage holes in the grinding ball was analyzed. The gating system was modified to optimize design by adding sand sleeves, shortening ingates and reducing the sprue size as well as other methods. The temperature field of the gating system optimized was simulated. The simulated results show that the optimized gating system can realize the sequential solidification, and shrinkage holes are transferred from the ball to the sprue. The simulated results are consistent with the actual casting ones.