3D Coupled Thermo-mechanical FEM Simulation In Precision Forging Process Of Blade

A blade is one of the most important mechanical components in an aero-engine. Precision forging of blade is a tendency for development of blade-forging technology. However, precision forging process of blade is high temperature and large deformation, there is heat transfer on billet - die interface, simultaneously plastic work and frictional work turn to heat, all these factors make temperature filed of billet continually change, the change of temperature field will affect deformation behavior of billet, furthermore affect the mechanical capability and microstructure of blade. Therefore, it is important to using 3D coupled thermo-mechanical FEM numerical simulation to research on precision forging process of blade for the optimization of precision forging technology and the development of its precision forging. A brief introduction to the project and its main results are as follows:The key technical problems of 3D coupled thermo-mechanical rigid-viscoplastic FEM simulation of blade forging process are studied systematically. Formulations to determine relaxation factor β are firstly established for rigid viscoplastic FEM adopting penalty function method, an improved cubic factor rapid algorithm derived from these formulations is proposed by combining with the advantage of advance and retreat search method. The results show that the algorithm can obviously improve convergence stability and reduce iteration steps.Based on 3D-PFS (3D Plastic Forming Simulation) system developed in our laboratory, a simulation system, 3D-CTM (3-Dimensional Coupled Thermo-mechanical Forming Simulation), for precision forging of the blade is developed. By applying 3D-CTM to cylinder upsetting, the results show that the system is reliable.A 3D thermal-mechanical coupling FEM simulation model corresponding to reality is set up for the precision forging process of the blade with tenon. By using the 3D-CTM system, the law of the blade precision forging process is revealed, and an important function of temperature in forming process is indicated. The influence ofdifferent deforming velocity, friction factor, die temperature and forging temperature of billet on the forming laws of precision forging process of blade is obtained.Based on a model which can be used to predict grain size of forging TC4 titanium alloy, gram size of the precision forging process of blade with tenon is computed by 3D-CTM system with different deformation parameters (deforming phases, velocity, friction factor and die temperature), and the influence of these deformation technological parameters on grain size is studied.