The mechanical modelling of components made of grey cast iron is a non-trivial task, especially when subjected to non-isothermal thermo-mechanical loading conditions. Hence, elasto-plastic deformations as well as time-dependent creep processes have to be taken into account in the simulation in order to accurately model the mechanical stress-strain relationship. Consequently, a methodology to simulate the complex deformation behaviour based on a damage modified viscoplastic constitutive model is introduced. This methodology also contains a semi-automated parameter optimization strategy featuring a genetic algorithm. The correspondingly conducted cyclic mechanical simulation runs match well with the experimental data. Only marginal deviations in the evaluated stress-strain hysteresis can be found at quite high temperatures.