空心管坯电磁离心过程的数值模拟

Numerical simulation on the electromagnetic centrifugal casting of tube blank

用有限元法模拟了铸造合金的流动和热量传输过程中瞬态速度场和温度场的分布,研究了电磁场 强度和离心机转速对电磁铸造空心管坯的影响．结果表明,电磁搅拌引起的熔体相对运动是凝固过程中晶粒 细化的主要原因．最优的电磁搅拌条件:转速1200 r／min,磁场强度为O．08 T,磁场持续加载25 s．在 一定的转速和磁场强度条件下电磁离心铸造的温度场和凝固时的温度梯度对凝固组织有重要的的影响．合 金液的外层,温度梯度达到最大值,铸件的温度下降得快,容易形成细小的等轴晶．

The effect of the electromagnetic intensity and the rotation speed of centrifugal machine on the electromagnetic centrifugal casting tube blank process were examined. The distribution of the instantaneous fields of velocity and temperature in centrifugal casting process were simulated. The results showed that a combination of fine structure and good property can be obtained if the electromagnetic field and rotation speed are suitable, and the relative flow of the molten alloy caused by the stirring of electromagnetic field is the main reason for grain refinement. If the rotation speed and electromagnetic intensity at the electromagnetic centrifugal casting process kept changeless, the temperature distribution and temperature grads were very important to the solidification structure. The fine equiax crystals were gotten at outer layer of molten alloy where the temperature grad got its minus maximum and the temperature decreased rapidly.