作者从铸铁件收缩量的不确定性和收缩速度的可变性出发,通过对铸件收缩和膨胀的动态叠加,冒口与铸件接触热节的分析,提出了均衡凝固理论与有限补缩原则。指出:铸铁件表观收缩时间就是冒口补缩作用中止时间。为此,冒口不必要晚于铸件凝固,冒口不应该放在铸件的热节上。 Based on the uncertainty of shrinkage of cast iron and the variability of shrinkage speed, the author proposed the principle of equilibrium solidification and the principle of finite shrinkage through the dynamic superposition of shrinkage and expansion of castings and the analysis of riser contact with the hot section of castings. Pointed out: cast iron apparent shrinkage time is the role of feeder riser suspension time. For this reason, riser does not need to be solidified later than casting, riser should not be placed on the hot section of casting.