Microstructure-informed creep model for 30CrMoNiV11-5 steel

30CrMoNiV11-5 is a high-strength rotor steel used in turbine shafts, where creep governs long-term performance under elevated temperature and stress. In this work, a physics-based mean-field creep (MFC) framework is developed, in which dislocation populations (mobile, immobile, and boundary) are coupled with precipitate-kinetics inputs and damage evolution arising from precipitate coarsening and cavitation. The precipitate state is obtained from thermo-kinetic simulations based on the alloy heat-treatment history. The model is calibrated against 7 standard creep tests at 550 °C over a stress range of 283–450 MPa. It successfully reproduces the primary–secondary–tertiary creep behaviour, captures the stress dependence of the minimum creep strain rate, and predicts rupture time with good fidelity. The predicted microstructural evolution is consistent with TEM and EBSD observations, and the model allows analysis of the respective roles of intragranular and boundary-related precipitates. The proposed framework provides a mechanism-based approach for creep-life assessment of 30CrMoNiV11-5 and related rotor steels.