脉冲磁场-机械振动复合处理对H62黄铜凝固组织和硬度的影响

Effect of Compound Treatment of Pulsed Magnetic Field and Mechanical Vibration on Solidification Structure and Hardness of H62 Brass

对比研究了未处理、脉冲磁场处理、机械振动处理和脉冲磁场-机械振动复合处理条件下H62黄铜的凝固组织的变化,并考察了复合处理条件下磁场参数和冷却条件对合金凝固组织和硬度的影响。结果表明:经脉冲磁场-机械振动复合处理后,初生α相由粗大、发达的树枝晶变成短小的棒状枝晶,且细化效果好于单一的脉冲磁场或机械振动处理;随着脉冲电压或频率的增加,初生α相逐渐退化,且硬度随之提高;随着浇注温度或铸型温度的增加,复合处理后,初生α相不断细化,硬度逐渐提高,但当铸型温度达到1 000℃时,初生α相有所粗化,硬度下降。

Solidification structure of H62 brass without treatment, with pulsed magnetic field treatment, mechanical vibration treatment and compound treatment of pulsed magnetic field and mechanical vibration were studied comparatively. The influences of parameters of magnetic field and cooling condition on solidification structure and hardness of the alloy with compound treatment were investigated. The experimental results show that solidification structure of H62 brass can be refined greatly by compound treatment during the course of solidification. Primary α phase is changed from coarse and well-developed dendrites to short and rod-shaped dendrites, which is more efficient than the refining effect of pulsed magnetic field or mechanical vibration treatment. With the increase of the pulse voltage or frequency, primary a phase degrades and hardness increases. Primary α phase refines gradually with the increase of pouring temperature or mold temperature with compound treatment. However, primary α phase is coarsened and hardness decreases when the mold temperature reaches to 1 000 ℃.