Residual Stress Evolution during Heat Treatment and Machining of Forged Ti-6Al-4V Turbine Engine Parts - Computational Simulation in Comparison to Experimental Investigations

摘要

Residual stresses resulting from the different hot-forming operations and intermediate heat treatments play an important role during manufacture as well as operation of complex shaped structures. An understanding of the residual stress evolution during the manufacturing process from the starting ingot material to the final part allows to predict possible machining problems and distortions that can occur. This paper is devoted to residual stress analysis of a forged high performance turbine engine part after heat treatments and machining. Based on an extensive material database the residual stress evolution during the production of a Ti-6Al-4V shaft is simulated. The numerical simulations are accompanied by stress measurements using neutron diffraction. Once the results of the simulations are verified, it can be used to optimize the forging process and the pre-form geometry. The current results show that the used heat treatments produce an almost stress-free final part. According to the experimental results, the employed simulation gives an excellent description of the physical processes occurring during manufacture.