中文摘要：

将亚共晶高铬铸铁铸态试样和半固态试样加热至液固温度区间保温，研究了保温过程中初生奥氏体形态和尺寸的演变过程。结果表明。两种试样保温过程中奥氏体晶粒都经历了粗化并趋于球化的发展过程，其粗化是由于溶质原子迁移和晶粒合并所导致。原始奥氏体形态决定其球化速度，含颗粒状奥氏体的半固态试样中奥氏体经历了简短的长大而球化过程。含枝晶状奥氏体的铸态试样中奥氏体先形成网状结构，然后经过复杂的熔断、长大过程，奥氏体球化速度极其缓慢。

英文摘要：

Cast samples and semi-solid samples of hypoeutectic high Cr cast iron were heated to a temperature between liquidus and solidus. The evolutions of primary austenite morphology and size during the course of the sample insulation were studied. The results show that the austenite grains in the course of the two kinds of samples insulation experienced the process of grain coarsening and globalization trend, and the grain coarsening is due to solute atoms migration and grain merging. Original austenitic shape determines its globalization speed. Austenite experienced a brief process of growing up and globalization in the semi-solid samples with particulate austenite. In the as cast samples containing austenite dendrites, the austenite mesh structure were formed firstly, then a complex process of fusing and growing is passed. Globalization speed of austenite is extremely slow.