经过试验及生产实践,证明了灰铸铁共晶转变时因析出石墨而产生体积膨胀力,它是造成灰铸铁膨胀裂纹的主要原因。在生产中,采取了降低碳当量、降低浇注温度、提前打箱、改变浇冒口位置、利用冷铁以及合金化等措施可防止这种缺陷的发生。 After tests and production practices, it is proved that the volume expansion force is caused by the precipitation of graphite during the eutectic transformation of gray cast iron, which is the main reason for the expansion crack of gray cast iron. In production, taken to reduce carbon equivalent, reduce the pouring temperature, pre-boxing, changing the location of pouring riser, the use of cold-iron and alloying measures to prevent such defects.