本文主要研究了在化学成分相同而石墨球大小和分布不同的两种铁素体球铁的断裂机理。在室温下进行机械试验,通过金相分析来完成。球径粗大的1号铸铁成分为C 3.42%;Si 2.53%;Mn 0.10%;S 0.005%;P 0.02%;Mg 0.04%;Sb 90ppm;球径细小的2号铸铁成分为C 3.4%,Si 2.53%;Mn 0.085%;S 0.005%;P 0.02%;Mg In this paper, we mainly study the fracture mechanism of two kinds of ferrite ductile iron with the same chemical composition and different size and distribution of graphite balls. Mechanical tests were conducted at room temperature and metallographic analysis was performed. The coarse cast iron No. 1 has a composition of C 3.42%; Si 2.53%; Mn 0.10%; S 0.005%; P 0.02%; Mg 0.04%; Sb 90 ppm; 2.53%; Mn 0.085%; S 0.005%; P 0.02%; Mg