Process for manufacturing forged titanium compressor wheel

A process for manufacturing a titanium centrifugal compressor wheel (1), said wheel including a hub with a hub axis and a plurality of backswept aerodynamic blades carried on the surface of the hub and defining air passages between adjacent blades, said process comprising:

• preparing a quantity of titanium or titanium alloy stock shaped to fit within a cavity in a segmented zero draft die and having a volume approximately equal to that of a forged part to be manufactured in the die;
• applying a protective coating to said stock;
• heating said coated stock and said segmented zero draft die while separated to approximately a predetermined optimum forging temperature for said stock at least as high as about 1200° F.;
• coating all segments of said die with a lubricant before positioning the stock therein;
• positioning the heated stock in the heated die;
• heating the die and contained stock further after assembly together and as necessary to give the combination said forging temperature;
• applying forging force to said heated segmented die to deform the heated stock toward the shape of said cavity to form a near net shape forged compressor wheel stock;
• separating the sections of said segmented die and removing the near net shape forged stock therefrom;
• finish machining the near net shape forged stock to the desired net shape including machining undercut areas and optionally blade leading edges.