脉冲电压对低过热过共晶高铬铸铁熔体凝固组织的影响

Effects of Pulsed Voltage on Solidified Microstructure of Low Overheat Melt of Hypereutectic High Chromium Cast Iron

对1360℃低过热过共晶高铬铸铁熔体冷却到液相线过程施加脉冲电流,研究了脉冲电压对其凝固组织的影响。结果表明,脉冲电流能够细化低过热过共晶高铬铸铁熔体凝固组织,初生碳化物由长杆状转化成规则的六边形块状或颗粒状。脉冲电流频率为45 Hz、脉宽为10μs、电压为500 V时,可以获得分布均匀,尺寸细小的初生碳化物,且其形貌均一,主要呈现为颗粒状。经脉冲电流处理后,合金共晶团的碳化物片层厚度和间距较未经处理时减小。

In the process of low overheat hypereutectic high chromium cast iron （HCCI） melt cooling from 1360 ℃ to liquidus, the pulsed current was applied and the effects of pulsed voltage on solidified microstmcture were analyzed. The results show that the pulsed current can refine the solidified the microstructure of low overheat melt of hypereutectic HCCI, the primary carbides transform from long rod into tiny fine hexagonal or granular carbides. When the pulsed current frequency is 45 Hz, the pulse width is 10μs, and the voltage is 500 V, the primary carbides with uniform distribution and small size can be obtained, and the morphology ofthe primary carbides is uniform, and it mainly presents as granular carbide. After pulsed current treatment, the eutectic carbides of the alloy are refined, and the thickness and spacing of carbides in eutectic clusters of the alloy decrease compared with those without treatment.