NEAR NET SHAPE FORGING OF TITANIUM-ALLOY TURBINE BLADE

The isothermal forging process has been developed to produce turbine blades made of near beta Ti-alloy Ti-10V-2Fe-3Al. It is important to set the preform at the optimum position of the die in order to get a high precision product. The deformation analysis by using FEM is effective to determine the optimum position. And also it is necessary to avoid buckling induced by the restriction of axial elongation of the material. As a result, Ti-10V-2Fe-3Al blades could be formed precisely by using only one stage of forging, and machining was needed only at the root. The thickness of the oxide layer induced on the surface of the forged blade was only 70-mu-m. The mechanical properties of Ti-10V-2Fe-3Al blades after forging and annealing were superior to those of Ti-6Al-4V blades and were nearly uniform across the length of the blades.