采用砂型工艺制备了铁素体球墨铸铁件, 对比了不同硅含量下锑对球墨铸铁件心部碎块状石墨的抑制作用, 分析了相同硅含量下壁厚对其心部共晶凝固时间、抗拉强度、屈服强度、伸长率及－40 ℃冲击性能的影响。结果表明: 添加微量锑对碎块状石墨有明显地抑制作用, 当硅质量分数在1.8%~2.0%和2.0%~2.2%时, 分别添加0.005%和0.008%的锑, 基本能完全抑制碎块状石墨的产生, 可明显提高其力学性能, 特别是塑性; 在相同锑含量下, 随着铸铁件壁厚的增加, 其共晶凝固时间延长, 各项力学性能均呈下降趋势。

Ferrite ductile iron casting was prepared by sand moulding process. The inhibition effect of Sb on chunky graphite in the center of ductile iron casting with different Si contents was compared. The effect of wall thickness of the castings with same Si content on the eutectic solidification time in the center, tensile strength, yield strength, elongation and low temperature impact property at -40 ℃ was analyzed. The results show that tiny addition of Sb had obvious inhibition effect on the chunky graphite. When the Si content was 1.8wt%-2.0wt% or 2.0wt%-2.2wt%, adding 0.005wt% or 0.008wt% Sb could completely inhibit the formation of chunky graphite and improve the mechanical properties significantly, especially the toughness. With the same Sb content, the larger the wall thickness was, the longer the eutectic solidification time was, and the lower the comprehensive mechanical properties were.