本文采用定向凝固方法，对共晶灰铸铁的凝固界面形态及其控制因素片状石墨奥氏体共晶生长中的碳扩散，共晶铸铁中初生奥氏体枝晶及枝晶间共晶的凝固特点，铸铁中石墨形态的转变规律及铸铁中的石墨形态与凝固界面形态之间的关系等问题进行了研究，、结果表明，石墨和奥氏体两相导热率与生长机制的差异，凝固速度的大小，是共晶灰铸铁凝固界面形态的控制因素。片状石墨，奥氏体共晶的生长界面呈锯齿状且生长速度越小，锯齿长度越大，界面呈锯齿状的片状石墨奥氏体共晶的生长过程不仅受液相扩散的控制．还受固相扩散的控制。亚共晶灰铸铁中奥氏体枝品间共晶的凝固也具有这些特点。随凝固速度增加，亚共晶灰铸铁的共晶温度下降，初生奥氏体枝晶的数量和发达程度随之增加。亚共晶白口铁的共晶温度，初生奥氏体枝晶的数量和发达程度都基本，上不随凝固速度而变化。铸铁中各种石墨形态之间的转变是逐渐过度的，不存在突变现象。因石墨结构的变化，蠕虫状石墨铸铁的凝固界面呈，一种特殊的胞状形态，球状石墨铸铁的凝固界面极不规则-

With the unidirectional solidification technique, some fundamental problems on cast iron solidification were studied in this paper, such as morphologies of solid/liquid interface and controlling factors of eutectic gray iron, carbon diffusion in the growth of flake graphite/austenite eutectic with a saw tooth-like interface, solidification characteristics of proeutectic austenite dendrites and interdendritic eutectic of hypoeutectic cast iron, modes of transition of graphite morphology in cast iron, relationship of solidification interface morphology versus graphite morphology etc. The main conclusions made were as follows.The differences in thermal conductivity and growth mechanism between graphite and austenite, and the solidification rate are the controlling factors on the morphology of solidification interface of eutectic gray iron.The morphology of growth interface of flake graphite/austenite eutectic is saw tooth-like, and the smaller the growth rate, the larger the length of the saw teeth. The growth process of flake graphite/austenite eutectic with a saw tooth-like interface is controlled not only by the diffusion in the melt, but also by the diffusion in the solid. The solidification of interdendritic eutectic of hypoeutectic gray iron has the same characteristics as eutectic gray iron. With the increasing of solidification rate, the eutectic Temperature of hypoeutectic gray iron decreases, the amount of proeutectic austenite dendrites increases. The eutectic temperature and the amount of proeutectic austenite dendrites are essentially unchanged with the variation of solidification rates in hypoeutectic white iron. It is further determined that the transition of graphite from one form to another occurs by a gradual change and Doesn’t occur in an interrupted manner. Due to the change of graphite structure the solidification interface of vermicular graphite iron becomes cellular-like, and the solidification interface of nodular graphite iron is rather irregular.