Process for manufacturing a hollow turbine blade and device used for on-going hot twisting

摘要

The procedure consists of forging, machining and welding components made by a computer-aided system, followed by inflation under pressure and superplastic moulding. The required twist in the blade, made from a titanium alloy such as TA6V, is produced by heating the blade to 700 deg C and applying a torsion to it through rotary bars (5) acting on yokes previously attached to the blade. The twisting process can be applied to the individual components of the blade or to assembled blades and uses a cylindrical electric furnace (2) with slits (24) for the bars. The furnace is surrounded by a circular frame (6), and jaws (3, 4) hold the two ends of the blade while it is being twisted.