Towards an accurate description of hot die forging-quenching-aging residual stress in GH4169 turbine disc

Hot die forging-quenching-aging (FQA) of superalloy turbine discs is a complex process with multi-field coupling constraints, which makes the accurate prediction of residual stress (RS) become an urgent challenge to be solved. In this study, hot compression tests of GH4169 with initial state (IM) and forged state (FM) and creep tests with FM and aged state (FAM) were performed. Comprehensive consideration of the influence of strain, strain rate, and temperature, a modified Arrhenius model was established to predict the deformation behaviors of IM. Considering the difference in deformation trend of FM over a wide temperature range from 600 to 1050 °C, a segmented model was established. During the creep tests of FM, an accelerated creep stage occurs at 500 MPa. The properties and creep threshold stress of the FAM increase due to the precipitation of strengthening phases at 720 °C/8 h, resulting in the creep strain at 620 °C close to 0. Thereby, a finite element model (FEM) for predicting the evolution of RS in the whole process was established, considering the temperature-dependent heat transfer coefficient in quenching process and deformation behaviors of GH4169 in three states. Using the verified FEM, the RS formation, transfer, superposition, influencing factors, evolution, and distribution uniformity in FQA process of turbine disc were clarified. The methods of this study could aid in controlling the RS of turbine disc during forming.