低压脉冲磁场对纯Al凝固组织和缩孔的影响

Effect of Low-voltage Pulsed Magnetic Field on Solidification Structure and Shrinkage of Pure Aluminum

研究了不同的脉冲磁场电压、脉冲频率及铸型预热温度对纯铝凝固组织和缩孔的影响。研究结果表明:低压脉冲磁场可使纯铝晶粒细化,等轴晶比例增加,缩孔深度减小;随着脉冲电压、脉冲频率或铸型预热温度的增加,纯铝的等轴晶比例逐渐增大,但当铸型预热温度达到700℃时,等轴晶比例略有减小;同时纯铝的中心缩孔深度逐渐减小,但当脉冲频率超过2.5Hz或铸型预热温度超过500℃时,中心凸起代替中心缩孔。

The effects of different pulse voltage, pulse fi＇equency of low-voltage pulsed magnetic field and preheating temperature of mold on solidification structure and shrinkage of pure aluminum were investigated. The results show that the grains of pure aluminum can be refined evidently by low-voltage pulsed magnetic field, the ratio of equiaxed grains increases and the depth of shrinkage reduces greatly. With the increase of pulse voltage, pulse frequency and preheating temperature of mold, the ratio of equiaxed grains of aluminum increases gradually, but when the preheating temperature of mold increases to 700℃, the ratio of equlaxed grains decreases slightly, at the same time, the depth of shrinkage reduces gradually, but when pulse frequency exceeds 2.5 Hz or preheating temperature of mold exceeds 500 ℃, the protuberance replaces the shrinkage.