Optimization In Design And Control In Production Of Isothermal Forging Processes For Titanium Alloy

Some important parts of aero-engine, such as turbine disk, force bearing disk, turbine blades and so on, are made of aerial materials difficult to deformation, like titanium alloy or high-temperature alloy. However, due to the shortage of design methods and methods of production, as-forged microstructure and property of forgings are instability but also the rate of finished products is low, so that it is very waste of human forces and materials.Based on the system study of deformation characters of Ti-6Al-4V alloy and virtual orthogonal experiments, taking the as-forged microstructure and property of isothermal disk-forging as objective function, the die isothermal forming process and the integrated technology of design and control of Ti-6Al-4V alloy in isothermal forming process have been analyzed with thermodynamic coupled FEM numerical simulation. The main research findings and new outlooks are as follows:(1) Based on a new constitutive equation of parallel model and mathematic theory of statistics, the relationship of as-forged recrystal microstructure distribution and technological parameters of forging was developed, providing a scientific basis for the optimum design of isothermal forming process of Ti-6A1-4V alloy.(2) Taking the as-forged microstructure uniformity as optimum objective function, the die isothermal forming process of Ti-6Al-4V alloy has been analyzed with the virtual orthogonal experiment that combined with FEM numerical simulation and orthogonal experiment, then its technological parameters was optimizing that is different with traditional ones, therefore, it provided a sound basis for the implemention of technological parameters and improvement of as-forged quality in forming process.(3) Based on the virtual orthogonal experiment results, technological parameters of Ti-6Al-4V alloy was further optimizing with regressive model and simplex method, a kind of optimizing algorithm, optimizing results have indicated that optimizing effect was obvious, then a new optimizing viewpoint that including virtual experiments, regression model and optimum design for technological parameters of Ti-6Al-4V alloy in isothermal forming process.(4) Based on an integrated method combined with thermodynamic simulation, microstructure simulation and computer numerical simulation and sensitivity analysis of linear program, taking the as-forged microstructure stability as control objective, the control of isothermal forming process of Ti-6Al-4V alloy was studied and with a three-layer control strategy, an new integrated technology of design and control based on PID control mode or sensitivity theory was proposed, thus,modernization updating control of forming process was realized, which has very obvious theoretical meaning and engineering application value in actual production.