本文认为采用冷却面积扩大法设计外冷铁方法简单、实用,数值计算法从铸件凝固角度揭示了铸件内部组织和缺陷形成的本质,计算精度高.如将两者结合起来,可成为一种较完整的既可靠又实用的外冷铁工艺设计技术.通过实验数据阐明了诸工艺因素,如铸件-冷铁间挂砂层厚度、冷铁厚度、铸件壁厚、铸件与冷铁间接触条件等,对冷却面积扩大系数K和铸件-冷铁间界面换热系数h两个参数的影响及规律. In this paper, it is considered that the method of expanding outer cooling iron by the method of cooling area expansion is simple and practical, and the numerical calculation method reveals the nature of the formation of internal structure and defects of the casting from the solidification point of the casting and has high calculation accuracy. A complete reliable and practical design technology of external cooling iron technology.Experimental data show that the process factors such as the casting - the thickness of the sand between the cold iron, the thickness of the cold iron, the wall thickness of the casting, the contact condition between the casting and the chill iron, etc. , On the cooling area expansion coefficient K and the cast - chill iron interface heat transfer coefficient h two parameters and the law.