球墨铸铁件凝固过程三维数值模拟

根据卡赛提出的球墨铸铁件补缩原理,本文对球墨铸铁件凝固过程中的体积变化进行直接数值模拟,将模拟结果换算整理成铸件表现密度与浇注结束后时间的关系曲线,按此曲线,可根据冒口颈封闭时间来判断收缩缺陷的有无及严重程度。数值计算中考虑了共晶前期的温度回升、铸件和铸型间的紧密接触、二次收缩和铁水回流等球墨铸铁件的特有现象。对于试样中的收缩缺陷的程度和位置,数值模拟结果与实验结果基本符合。

3-DIMENSIONAL NUMERICAL SIMULATION OF SOLIDIFICATION OF DUCTILE IRON CASTINGS

In light of the feeding principle for ductile iron castings proposed by S. I. Karsay, the numerical simulation of the volume variation of a ductile iron casting in solidification process was carried out. Using the results of simulation. a plot of the apparent density of the casting against the time after pouring was made. According to the plot, the degree of shrinkage defect could be evaluated from the time when the riser neck was frozen. The following special pheno- mena in solidification process of ductile iron castings were considered in the simu- lation: temperature recovery in the early stage of eutectic reaction, perfect con- tact between the casting and the mold, secondary contraction and extrusion of liquid iron from the casting to the riser. In the sight of degree and position of shrinkage defect in the casting, the results of the present numerical simula- tion coincided with those of the experiment basically.