Application of θ projection method in analysis of creep deformation of turbine disc

The creep deformation of direct aging ZSGH4169 turbine disc was studied. Firstly, a θ projection model with 16 parameters was established to characterize the creep behavior of the ZSGH4169 superalloy at different temperatures and loads. Secondly, the corresponding user subroutine combined with the general finite element program was developed, and the calculation precision was also validated. Thirdly, the model was used to simulate the creep deformation of the turbine disc. The calculated results show that the model can describe three stages of creep behaviors of ZSGH4169 under 650℃ and 700℃. Compared with the conventional models such as Norton rate model, the model had greater modeling capability and higher accuracy, so it could be used particularly in case of the change of the loading and temperature. Furthermore, the long-time creep deformation and stress relaxation of the turbine disc at the center hole and bolt hole were obtained, providing a guidance for the engineering design.