脉冲电流参数对过共晶高铬铸铁近液相线熔化后凝固组织的影响

Effect of electric current pulse parameters on the solidification microstructure of hypereutectic high-chromium cast iron near-liquidus melted

  • 摘要: 对过共晶高铬铸铁近液相线溶化后的凝固过程进行脉冲电流处理,研究了脉冲电流参数(脉冲电压和频率)对凝固组织的影响.发现脉冲频率和电压的增大都有助于过共晶高铬铸铁凝固组织中碳化物的细化和粒化.脉冲频率的增大促进大量细小颗粒状初生碳化物的析出,离异共晶现象变得更加明显,层片状共晶碳化物减少.脉冲电压的增加促进初生碳化物细化和粒化,片状共晶碳化物变短.过高的电压也促进离异共晶,导致更多的初生碳化物的形成.

     

    Abstract: Solidification of hypereutectic high-chromium cast iron samples near-liquidus melted was treated with electric current pulse (ECP). The effects of ECP parameters such as electric voltage and pulse frequency on the solidification microstructure were investigated during the treatment. It is found that increasing the pulse frequency or electric voltage is helpful to carbide refinement and granulation in the cast iron. The increase of pulse frequency promotes the precipitating of a large number of fine granular primary carbides and the occurrence of a divorced eutectic reaction, which lead to the decrease in number of lamellar eutectic carbides. The increase of electric voltage contributes to the primary carbides refining and granulating as well as the lamellar eutectic carbides shortening. An excessive voltage value can also be favorable to the occurrence of a divorced eutectic reaction and the formation of additional primary carbides.

     

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