【摘要】 在铸态高韧性球墨铸铁QT400-18凝固过程中进行电脉冲处理，电脉冲参数为电压2 600 V,频率0.88 Hz,电容200μF,处理时间15 min。施加脉冲电流后，石墨球圆整度改善，数量增加，粒径减小。同时运用固体与分子经验电子理论(EET)计算了价电子结构，从电子结构层次看，球墨铸铁在非平衡凝固中受相结构中最强共价键上的共用电子对数n_A控制，其表征原子间结合力的强弱或相分解或重构的难易程度。电脉冲作用球墨铸铁熔体相比未进行电脉冲处理的相同熔体过冷度增加12 K,同时根据“类拖曳效应的价电子理论模型”,电脉冲的施加加强了熔体中n_A较大的团簇的“类拖曳效应”,增大了平衡与非平衡共晶温度间隔，使得石墨更易形核，因此脉冲电流作用熔体具有促石墨化作用。更多还原

【Abstract】 The solidification process of as-cast high toughness ductile iron QT400-18 was treated by electric pulse. The parameters of electric pulse were voltage 26 00 V, frequency 0.88 Hz, capacitance 200 ΜF, and treatment time 15 min. After applying the pulse current, the roundness of the graphite ball was improved, the number was increased, and the particle size was reduced. At the same time, the valence electron structures were calculated by empirical electron theory of solids and molecules(EET). At the level of electronic structure, the non-equilibrium solidification of ductile iron was controlled by the shared electronic logarithm n_A of the strongest covalent bond in the phase structure. It characterized the strength of the binding force between atoms or the ease of phase decomposition or reconstruction. The undercooling of spheroidal graphite cast iron melt treated by electric pulse increased by 12 K compared with the same melt without electric pulse treatment. According to the“Model of valence electron theory of drag-like effect”, the“Drag-like effect” of larger n_A clusters in the melt was strengthened by electric pulse, and the temperature interval between equilibrium and non-equilibrium eutectic was increased, it made graphite easier to form nucleation, so pulse current had the effect of promoting graphitization.更多还原