As the power density of an engine increases

so does the temperature and stress that the cylinder head is subjected to during operation. Therefore

creep damage prediction needs to consider accurate creep constitutive models and parameters. Aiming at the wide range of temperature and stress working conditions of the compacted graphite cast iron (CGI) cylinder head

CGI creep test was carried out at 450-550 °C and 100-300 MPa. The comparative study of creep constitutive models to characterize the minimum creep rate of CGI under a wide range of temperature and stress was carried out. The research shows that compared with a smaller range of temperature and stress

CGI is more prone to creep damage under wide conditions. and temperature can promote the creep deformation of CGI more than stress. Based on the Norton-Bailey power law model

the Garofalo hyperbolic sine model

and the deformation mechanism-based true stress (DMTS) model respectively

combined with the multi-objective optimization method

the CGI creep constitutive model was constructed. Among them

73% of the predicted values of the CGI creep model based on the DMTS model are within twice the error range

and the coincidence effect is the best among the three models.