| TC27 titanium alloy is the domestic independent research and development of a new type of high strength, high toughness and high hardenability near-β titanium alloy. It can be used prospect in aviation, spaceflight and tracked vehicle structure. TC27 titanium alloy forgings internal inevitably existing deformation of the defective tissue by its forging process, it is hard to obtain the high quality forgings.In this paper, the method integrated with DMM and FEM technology was adopted on simulating and predicting the microstructure during forging process, based on intrinsic workability and state-of-stress workability. This method can be used in the predicting of microstructure, and further optimizing process parameters in the TC27 titanium alloy forging process of the balance elbow. The research result has a great significant guiding significance and practical application value, for obtaining good performance forgings without defects.According to processing map technology and Prasad criterion TC27 titanium alloy under different strain of instability, and determine the thermodynamic parameters window of instable microstructure: in the temperature ranges and the strain rate ranges of 700℃~850℃ and 0.25s-1~70s-1, 850℃~900℃ and 0.6s-1~70 s-1, 900℃~1000℃and 1s-1~70s-1,1000℃~1080℃and 0.5s-1~70s-1, 1080℃~1200℃and 0.3 s-1~70 s-1。The boundary conditions of thermodynamically parameters of instable microstructure, which were determined by instable map and power dissipation map respectively have been introduced into finite element model through the secondary development of Deform3 D commercial finite element software. Use it, the evolutions of instable microstructure for hot compression process of titanium alloy TC27 had been simulated and predicted under the deformation parameters of 900℃/0.1s-1, 900℃/1s-1 and 900℃/10s-1. The results as follow: when the compression parameters was 900℃/0.1s-1, it was stable microstructure during whole hot compression process, when the compression parameters was 900℃/1s-1, the instable microstructure Successively appeared in the center of mid part and the external circumference of terminal part, then the instable microstructure gradually expand to most parts of sample; when the compression parameters was 900℃/10s-1, it was instable microstructure during whole hot compression process.The Forgings forging process of TC27 alloy had been simulated by using the secondary development of Deform3 D commercial finite element software, The change of geometry, evolution law of the temperature field、strain field、stress field、force Load and instable microstructure in forging process of forging were studied. The results as follow: the instable microstructure first appeared in corner part, with the increase of loading step, the instable microstructure gradually expand to other parts, the external circumference of terminal part and bridge section of flash tank appeared the instable microstructure.In this paper, a L16 orthogonal experiment is designed based on the analysis of the type slot filling quality, instable microstructure, Load force on process parameters. How much factors as billet shape size, friction factor, initial forging temperature, speed of hydraulic press influence on type slot filling quality, instable microstructure, Load force are studied. The results show that billet shape size is primary factors affecting to type slot filling quality, speed of hydraulic press influences instable microstructure most, and initial forging temperature had a significant impact on Load force.According to the optimization design, the optimal parameters are obtained as follows: the billet shape size is s4, friction factor is 0.3, initial forging temperature is 910℃, speed of hydraulic press is 1mm/s. |
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