The effects of Si content, graphite volume fraction and pearlite volume fraction on the thermal conductivity of ductile iron were studied based on theoretical model analysis. Calculated results showed that the thermal conductivity of ductile iron was more sensitive to Si content compared with the volume fractions of pearlite and graphite. The key method to design and develop high thermal conductivity ductile iron was to control the Si content. Within 0.9–2.2 wt.% Si content, experimental results showed that with the increase in Si content, the thermal conductivity of ductile iron decreased dramatically, and the yield strength and tensile strength of ductile iron almost linearly increased, but the elongation remained almost unchanged. The dependence of thermal conductivity of ductile iron on temperature changed from monotonic decreasing to increasing first and then decreasing. Finally, we broke the common composition range of ductile iron and designed a new high C (≥ 3.9 wt.%) and low Si (1.0–1.4 wt.%) ductile iron with super-high thermal conductivity and elongation. Its thermal conductivity exceeded 40 W/(m K) within 27–300 °C, and maintained at 35–40 W/(m K) at 500 °C. The elongation was over 25%, and the tensile strength was more than 300 MPa.

在理论模型分析的基础上，研究了硅含量，石墨体积分数和珠光体体积分数对球墨铸​​铁导热系数的影响。计算结果表明，与珠光体和石墨的体积分数相比，球墨铸铁的热导率对Si含量更为敏感。设计和开发高导热率球墨铸铁的关键方法是控制Si含量。在0.9–2.2 wt。％的Si含量范围内，实验结果表明，随着Si含量的增加，球墨铸铁的导热系数急剧下降，球墨铸铁的屈服强度和拉伸强度几乎呈线性增加，但伸长率几乎保持不变。球墨铸铁的导热系数对温度的依赖性从单调降低到先升高再降低。最后，我们突破了球墨铸铁的常规组成范围，并设计了一种具有超高导热率和伸长率的新型高C（≥3.9 wt。％）和低Si（1.0–1.4 wt。％）球墨铸铁。它的热导率在27–300°C时超过40 W /（m K），在500°C时保持在35–40 W /（m K）。伸长率超过25％，抗拉强度超过300MPa。