Numerical Simulation Of Ta15 Alloy Forging Process

TA15 alloy is a near-α titanium alloy. The deformation of the TA15 alloy is difficult because of narrow process window, local overheating and high resistance of deformation, To understand the deformation behavior and the effect of process parameters on deformation of the TA15 alloy during high temperature forming and decrease wasting of time, man power and cost, It is well known that FE technology is a perfect method and has played important part in the study on the metal forming processes, which can provide scientific foundation for predicting whether defects occurring or not and determining the optimal process parameters.In this paper, the high temperature deformation behavior has been investigated and the processing map of TA15 alloy has been established according to dynamic materials modeling, which can make certain the optimal parameters during the isothermal deformation. Based on the characteristics of the stress-strain curves of the TA15 alloy during high temperature deformation, a flow stress model of TA15 alloy during high temperature deformation has been established by the isothermal compression. In the flow stress model, the effect of these thermomechanical parameters on temperature, strain rate and strain has been taken into account. Furthermore, it is capable of revealing effectively the high temperature deformation behavior during isothermal forging processes. Meanwhile, the present model is checked. The comparison of the calculated results with the experimental of the test samples shows that the average error of flow stress is not more than 7.65%, which is proofed that present constitutive relationship has a good reliability and can offer the essential prerequisites for improvement of numerical simulation precision of metal forming processes.Integrating the constitutive relationship into the FE code, a coupled simulation of deformation with heat transfer has been carried out for the connecting piece isothermal forging of TA15 alloy. The effect of process parameters, including the deformation temperature, the punch velocity, the round radius and friction on the stress, strain and temperature raise during isothermal forging has been studied and load-journey curves with different thermomechanical parameters has been calculated. The results investigated show that punch velocity and deformation temperature have significant effect on the workpiece forming. Moreover, the effect of different deformation wayson the deformation process of TA15 alloy connecting piece has been given out. This work provides the theory and technique foundation for implementing process optimized design and quality control scheme of TA15 alloy connecting piece isothermal forging process.