(1) Modulus method: in 1986, when Lin Rui of Harbin University of science and technology was developing the large section ductile iron end cap, he poured the cube with the same modulus as the end cap casting under the same production conditions. By studying the solidification characteristics of the cube, he mastered the quality control measures of the end cap

(2) Solid dissection method: in order to test the structure and properties of 100 ton ductile iron nuclear spent fuel container produced in Japan in 1987, dissection tests were carried out at different thicknesses and heights.

(3) Physical simulation: under the same production conditions, a representative part of the casting is used to replace the casting, so as to master the quality control measures of the casting.

(4) Numerical simulation: use numerical simulation software to simulate the temperature field, filling and solidification process of castings, evaluate the location and types of defects, and then adjust the casting process, so as to improve the structure and properties of castings, save production costs and shorten the development cycle.

The module method is generally cubic block, which can not simulate the solidification process of castings well; the solid dissection method is suitable for small and medium-sized castings, which is neither realistic nor economical for large and heavy castings; the physical simulation has the problem of long production cycle in the development of heavy castings; although the numerical simulation can simulate the solidification process of castings, it needs experimental data to support. To sum up, this project adopts the method of combining numerical simulation with experiment.