Effects of Initial Forming Temperature on Primary Alpha Evolution during Radial-axial Ring Rolling for TA15 Titanium Alloy

The volume fraction of primary alpha, which is the key microstructure parameter and determines the mechanical properties of the titanium alloy ring, is strongly affected by the initial forming temperature in the radial-axial ring rolling of titanium alloy. In this paper, a primary alpha evolution model is implemented into the 3D-FE model of radial-axial ring rolling process to model the primary alpha evolution of the TA15 titanium alloy ring. Both transferring and deforming stages of the process are considered in the FE model. By FE simulations, it is found that the volume fraction of primary alpha of the rolled ring is mainly determined by the transferring stage, and decreases with the increase of initial forming temperature. Consequently, the reasonable range of the initial forming temperature has been determined for the radial-axial ring rolling of TA15 titanium alloy.