Abstract: Turbine vane segments having outer and inner bands and a vane extending therebetween are welded one to the other by E-beam welding along their adjoining margins and from the outside of the bands. The adjoining margins on the hot gas path sides of the outer and inner bands are chamfered, TIG-welded and machined to provide a smooth, continuous gas path surface. The aft hook of each segment is cut back to provide inset faces in a radially projecting flange and a flange extending axially from the radial flange. A filler piece having a body shaped to correspond to the shape of the space between the inset faces of the radial flange is E-beam welded to the radial flange. Gaps between a tongue on the filler piece and the inset faces of the axially extending flange are provided with weld filler material and TIG-welded to complete the welding of the aft hook.

Abstract: A turbine stator vane includes outer and inner walls each having outer and inner chambers and a vane extending between the outer and inner walls. The vane includes first, second, third, fourth and fifth cavities for flowing a cooling medium. The cooling medium enters the outer chamber of the outer wall, flows through an impingement plate for impingement cooling of the outer band wall defining in part the hot gas path and through openings in the first, second and fourth cavities for flow radially inwardly, cooling the vane. The spent cooling medium flows into the inner wall and inner chamber for flow through an impingement plate radially outwardly to cool the inner wall. The spent cooling medium flows through the third cavity for egress from the turbine vane segment from the outer wall. The first, second or third cavities contain inserts having impingement openings for impingement cooling of the vane walls. The fifth cavity provides air cooling for the trailing edge.

Abstract: A steam-cooled second-stage nozzle segment has an outer band and an outer cover defining a plenum therebetween for receiving cooling steam for flow through the nozzles to the inner band and cover therefor and return flow through the nozzles. To measure the temperature of the buckets of the stage forwardly of the nozzle stage, a pyrometer boss is electron beam-welded in an opening through the outer band and TIG-welded to the outer cover plate. By machining a hole through the boss and seating a linearly extending tube in the boss, a line of sight between a pyrometer mounted on the turbine frame and the buckets is provided whereby the temperature of the buckets can be ascertained. The welding of the boss to the outer band and outer cover enables steam flow through the plenum without leakage, while providing a line of sight through the outer cover and outer band to measure bucket temperature.

Abstract: A post-cast EDM process is used to remove material from the interior surface of a nozzle vane cavity of a turbine. A thin electrode is passed through the cavity between opposite ends of the nozzle vane and displaced along the interior nozzle wall to remove the material along a predetermined path, thus reducing the thickness of the wall between the cavity and the external surface of the nozzle. In another form, an EDM process employing a profile as an electrode is disposed in the cavity and advanced against the wall to remove material from the wall until the final wall thickness is achieved, with the interior wall surface being complementary to the profile surface.

Abstract: Turbine vane segments having outer and inner bands and a vane extending therebetween are welded one to the other by E-beam welding along their adjoining margins and from the outside of the bands. The adjoining margins on the hot gas path sides of the outer and inner bands are chamfered, TIG-welded and machined to provide a smooth, continuous gas path surface. The aft hook of each segment is cut back to provide inset faces in a radially projecting flange and a flange extending axially from the radial flange. A filler piece having a body shaped to correspond to the shape of the space between the inset faces of the radial flange is E-beam welded to the radial flange. Gaps between a tongue on the filler piece and the inset faces of the axially extending flange are provided with weld filler material and TIG-welded to complete the welding of the aft hook.

Abstract: A post-cast EDM process is used to remove material from the interior surface of a nozzle vane cavity of a turbine. A thin electrode is passed through the cavity between opposite ends of the nozzle vane and displaced along the interior nozzle wall to remove the material along a predetermined path, thus reducing the thickness of the wall between the cavity and the external surface of the nozzle. In another form, an EDM process employing a profile as an electrode is disposed in the cavity and advanced against the wall to remove material from the wall until the final wall thickness is achieved, with the interior wall surface being complementary to the profile surface.