Constitutive Relationship Of TC18Titanium Alloy And Its Application In Isothermal Die Forging Of Disc Component Using Finite Element Method

Some crucial disc components of aero-engine, such as turbine disk, force bearing disk and so on, are made of difficult-to-deformation materials like titanium alloy or high-temparature alloy by forging process. However, forging process is a highly nonlinear and complicated aggregation. Due to the shortage of design methods, it will have a negative effect on the stability of forgings and the rate of finished products is also low. Therefore, investigation into the influence of defomation parameters on the formability of disc through deformation-heat transfer simulation have some theoretical significance and practical value for the development of forging process.Based on the system study of deformation characters of TC18alloy, a Arrhenius constitutive relationship was obtained from thermal simulation compression experiments. Then, a series study of numerical simulation and experiments of one-passroller and muti-pass rolling process at different deformation conditions for TC18plate have been carried out by applying the constitutive equation to the software of DEFORM-3D. The simulated and experimental results have been compared to prove the reliability of the constitutive equation, either. The rule of isothermal die forging process for reduced-scale TC18disc have been taken into account through systemically investigating the influence of different conditions, and finally guided the real experiment. The main research findings and new outlook are as follows:(1) Constitutive equation during hot simulation deformation have been established and verified through the experimental data under the condition of800-950℃and0.01-10s-1, the error between the equation and experimental data is smaller than10%.(2) Simulation are well presented the rule of formability, the laws of crack formation and dimensional change of TC18rolling process. The suitable rolling temperature is above800℃;0.68is the critical damage value of crack formation; The error in spreading width and rolling length between simulating and experimental results are less than1%and5%at each lane, respectively.(3) Process parameters of isothermal die forging for reduced-scale TC18disc are optimized by analyzing the simulated results. The suitable height-diameter ratio is between0.26-1.18, deformation temperature is840℃, deformation rate is0.1mm/s, and friction factor is0.03by using glass lubricant. The reduced-scale TC18disc is successfully fabricated under the suitable conditions, which is in accordance with the simulating results.