The relationship between stress, strain, strain rate and temperature of materials is its inherent property. There are many studies on the constitutive equation of materials. The most direct and effective way is to use dynamic impact equipment. This method can truly reflect the relationship between macro stress, strain, strain rate and temperature, and accurately describe the relationship between stress, strain, strain rate and temperature, It is the key to establish the material constitutive equation and improve the accuracy of cutting simulation.

There is little research on the constitutive relationship of vermicular cast iron. In the cutting simulation of vermicular cast iron, the default constitutive equation of software or the constitutive equation of similar materials are mostly used. In this chapter, the JC constitutive equation of vermicular cast iron is fitted by analyzing the dynamic mechanical behavior of vermicular cast iron.

The dynamic mechanical behavior of compacted graphite cast iron gjv450 was studied, the constitutive equation of gjv450 was established and verified by experiments.

(1) The dynamic mechanical behavior of gjv450 in the range of sooos-moooos-1 strain rate at 20 ° C, 200 ° C, 400 ° C and 600 ° C was studied by Hopkinson compression bar experiment. The results show that gjv450 material has obvious thermal softening effect, and the thermal softening law corresponding to different strain rates remains unchanged; At different temperatures, there are strain rate strengthening effect and strain rate softening effect, and the regularity of the effect of strain rate on mechanical properties is not strong.

(2) The J-C constitutive equation of gjv450 at high temperature and high strain rate is established. The cutting simulation experiment is carried out to verify the effectiveness of the constitutive equation.