GH738高温合金热变形过程显微组织控制与预测 II．组织演化模型验证与应用

Microstructure evolution models of dynamic recrystallization, meta-dynamic recrys- tallization, static recrystallization and grain growth behavior for GH738 superalloy were implanted into finite element software MSC. SUPERFORM with FORTRAN language by means of the user subrou- tines, in order to add the function of predicting microstructure evolution during hot forging to MSC. SUPERFORM. Microstructure evolution models of GH738 superalloy and the feasibility of the redevel- oped MSC.SUPERFORM were verified by comparison between the simulated and experimental results on hot compression specimens and a turbine disc 250 mm in diameter. The numerical simulation of the forging turbine disc 1250 mm in diameter was carried out by the redeveloped MSC.SUPERFORM, showing that hot working window was in temperature range of 1040—1100 , strain rate range of 10— 25 mm/s. Comparison between simulated and actual forging results in the condition of 1080 , 10 mm/s showed that the simulated microstructure was in good agreement with the actual result. Besides, the numerical simulation of the forging turbine disk 1400 mm in diameter was also carried out using redeveloped MSC.SUPERFORM. Therefore, the construction of microstructure evolution models of GH738 superalloy and the feasibility of the redeveloped MSC.SUPERFORM are of great significance to accurate control and prediction of turbine disc microstructure.