Abstract: Steam turbine bucket covers have forward and aft clearance surfaces on a pressure side edge of the cover, a contact surface between the clearance surfaces and an undercut fillet between the forward clearance surface and the contact surface. The adjoining bucket cover has forward and aft clearance surfaces, a contact surface between the clearance surfaces and an outside radius between the forward clearance surface and the contact surfaces along the suction side edge of the cover. The undercut fillet includes two different radii to minimize or eliminate fretting damage caused by high stresses in the interference fit between the contact surfaces of adjacent covers.

Abstract: A new high-strength titanium-based alloy bucket specifically suited for use as the last stage buckets in steam turbine engines having vane lengths of about 40 inches or greater and the method for forming such bucket. Exemplary buckets according to the invention are formed from a titanium-based alloy containing up to about 6.25% aluminum; (b) about to 3.5% vanadium; (c) about 2.25% tin, (d) about 2.25% zirconium, (e) about 1.75% molybdenum, (f) about 2.25% chromium, (g) about 0.7% silicon; and (h) about 2.3% iron, with the balance being titanium. After forming, the bucket can be heat treated to provide stress relief and then machined in a conventional manner.

Abstract: A steam turbine blade includes a shank portion and an airfoil portion. The airfoil portion is formed with at least one pocket filled with a polymer filler material chosen as a function of natural frequency impact on the turbine blade or as a function of the damping characteristics of the filler materials. A steam turbine rotor wheel includes a plurality of blades secured about a circumferential periphery of the wheel, each blade having one or more pockets in the airfoil portion, the plurality of blades divided into two groups of blades. The pockets of one group of blades are filled with one or more polymer filler materials, and the pockets of the other group of blades filled with one or more polymer filler materials, wherein the polymer filler materials in the one group of blades creates different natural frequencies or damping characteristics in the blades of the one group than the polymer filler materials in the blades of the other group.

Abstract: A bucket for use on a steam turbine rotor wheel, the bucket comprising a shank portion and an airfoil portion, the airfoil portion having a radially outer tip with a tip cover adapted to be engaged, in use, by a similar tip cover on an adjacent bucket, wherein a radial step is formed in the tip cover and the airfoil portion along a leading edge of the airfoil portion.