低频电磁水平半连续铸造中磁场的分布及其对宏观偏析的影响

采用数值模拟的方法研究了低频电磁水平半连续铸造7075铝合金中不同强度及频率的磁场在熔体中的分布,并采用试验的方法研究了不同条件的磁场对铸锭宏观偏析的影响.将使用传统水平半连续铸造生产出的铸锭与低频电磁水平半连续铸造生产的铸锭进行了比较.研究结果表明:在传统水平半连续铸造工艺条件下,铸锭中易出现较严重的负偏析及重力偏析;然而,在低频电磁水平半连续铸造过程中,低频电磁场的存在明显削弱了铸锭中的宏观偏析.此外,磁场在熔体中的分布情况将直接影响其作用效果,提高磁场强度及适当降低磁场频率均有利于对宏观偏析的改善.

Distribution of Magnetic Field and Its Effects on Macrosegregation of Electromagnetic HDC Casting Aluminum Alloy

The distributions of electromagnetic fields with different intensities and frequencies in melt in electromagnetic HDC casting process were examined by numerical prediction, and the influences of low frequency electromagnetic field with different conditions on macrosegregation in HDC casting process were investigated experimentally. The ingots manufactured by conventional HDC and low frequency electromagnetic HDC casting were compared. The results show that the application of low frequency electromagnetic field can reduce macrosegregation in HDC casting process. Moreover, the distribution of magnetic field has great effect on the reduction of macrosegregation, and enhancing electromagnetic field density and reducing frequency properly are both benefit for the improvement of macrosegregation.