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Turbine Components Corporation

Ralph T DeMusis

Salvatore J Cretella

Matthew Bernardo

A method of restoring the shroud of a turbine blade which has become worn, and particularly those edges of the shroud in the vicinity of what is commonly known as the Z-notch, which comprises the steps of grinding down the shroud in the vicinity of said notch to an accurately predetermined dimension with respect to the original geometry of the shroud, placing the blade in a fixture having a masking member with a slot in it, such that the Z-notch of the blade is disposed substantially in alignment with the slot, and depositing, by means of a plasma spray, a metal alloy onto those edges in an amount just sufficient to build up the same essentially to their original dimensions. Following the plasma spraying, the built-up edges are sintered at a temperature on the order of 1900.degree. F. or more, to more firmly bond the built-up layer to the base metal. The blade is then cooled. The resulting edges conform so closely to the original geometry of a new blade that no additional refinishing or grinding operations are normally required after the sintering.

Method of restoring the shrouds of turbine blades

A method of restoring the shroud of a turbine blade which has become worn, and particularly that edge of the shroud in the vicinity of what is commonly known as the Z-notch, which comprises the steps of grinding down the shroud in the vicinity of said notch to an accurately predetermined dimension with respect to the original geometry of the shroud, placing the blade in a fixture having a masking member with a slot in it, such that the Z-notch of the blade is disposed substantially in alignment with the slot, and depositing, by means of a plasma spray, a metal alloy onto the edge in an amount just sufficient to build up the same essentially to its original dimension. Following the plasma spraying, the built-up edge is sintered at a temperature on the order of 1900.degree. F. or more, to more firmly bond the built-up layer to the base metal. The blade is then cooled. The resulting edge conforms so closely to the original geometry of a new blade that no additional refinishing or grinding operations are normally required after the sintering.

The method of restoring the worn edge surfaces of the shroud portion of a turbine component, such as a blade of the type having a ribbed mounting base at one end, which involves the steps of applying welding material to the worn edges of the shroud portion so as to build up the same beyond the dimensions of the shroud of a new component, and thereafter clamping the blade by its base in a fixture having a reference surface with a fixed position-relationship with respect to one edge of the shroud of a new blade of the type being refurbished when said new blade is similarly clamped in the fixture, and grinding off the added or overlay metal from the one edge of the built-up shroud until such edge is restored and duplicates the fixed relationship with respect to the reference surface. Thereafter the blade is clamped in a second fixture which has a supporting surface so arranged as to back up the one restored edge and thereby accurately position the blade with respect to the fixture, and then a remaining one of the built-up edges is restored. Finally, the blade is clamped in a third fixture having multiple surfaces backing up respectively the one restored edge and the remaining restored edge, while a third edge of the shroud is resurfaced. The method is characterized by high accuracy and good repeatability; excellent uniformity between successive units being refurbished thereby results.

Method of restoring worn turbine components

A refurbished turbine vane or blade. Used turbine vanes and blades are cleaned, annealed and in some cases slotted adjacent their ends, after which any cooling passages are welded closed and all cracks welded over, on both leading and trailing edges. The trailing edge, for a vane or blade having a short chord, is built up by welding along its full length with an alloy wire, after which any slots that were cut adjacent the ends are closed, also by welding. Then the worn surfaces of the vane or blade are built-up by a plasma spray process, using a metal powder with added silica, to a thickness as great as 30 to 40 thousandths of an inch. The built-up vane or blade is then sintered and thereafter surface finished to conform to the original contour of the component when new. Any cooling holes are finally recut, and the vane or blade polished as required and inspected.

Refurbished turbine components, such as vanes or blades

A machine for resurfacing the air-foil surfaces of turbine vanes and the like, comprising a base and a carriage movable over the base toward a work-performing station thereof. The base carries a power-driven abrasive belt which extends past the work-performing station, for engagement with the air-foil surface of the vane to be resurfaced. The latter is rotatably mounted on the carriage so as to be capable of turning during its engagement with the belt. The movement of the carriage over the base is governed by a cam and cam follower on the two parts, respectively, and a linkage is provided for effecting simultaneous synchronous turning of the cam and the vane. The arrangement is such that the position of the carriage with respect to the base is determined by the rotary position of the cam, and thus the contour of the latter affects the amount of resurfacing of the vane which occurs.

Turbine vane air-foil surface grinder

A method for repairing turbine vanes and the like which have become worn or cracked after extended periods of use. The method embraces the steps of applying molten metal containing a predetermined quantity of silicon to the cracks, and overall to the worn or eroded areas of the vane to build up the same beyond its original surface, sintering the vane in a furnace at a temperature of over 2,000.degree. F thereby burning off some of the silicon, allowing the vane to cool, and thereafter placing it in a high pressure furnace and subjecting it simultaneously to heating to a temperature in excess of 2,000.degree. F and a pressure in excess of 15,000 PSI to drive the build-up material into all of the cracks of the vane and simultaneously effect a densification of the material as well as improving the bond to the original eroded surfaces. Thereafter the vane is removed and allowed to cool, and the built-up surface of the vane is ground down so as to restore the dimensions of the piece substantially to those of a new part.

Method of refurbishing turbine vanes and the like

A method of refurbishing the air seal flanges of turbine blades which have become worn, comprising the steps of adding a bead of welding material to the opposite side portions and the edge portions of the flange so as to build up those areas which have been worn away, and thereafter removing controlled amounts of the built up areas so as to restore the piece to its original geometry. In the latter step, the blade is clamped in a first machine having a pair of abrasive belts and a pair of pivotally mounted pressure shoes engageable with the backs of the belts respectively, such that their abrasive surfaces can be brought into engagement with the opposite sides of the air seal flanges. Controlled quantities of the built-up flange can be removed, depending on the degree of advancement of the shoes. In another machine, the blade is placed on a slide which approaches an abrasive belt backed by a special curved contour shoe, whereby as the edge of the seal engages the abrasive surface of the belt, the latter yields an extent, conforming to the particular contour of the shoe. This has the effect of imparting a predetermined, desired profile to the flange. Following the welding and refinishing operations, the geometry and physical characteristics of the refurbished blade closely resemble those of a new blade. By the above method, considerably less expense is entailed over that involved with discarding the old blades and fabricating new ones.

Method of refurbishing turbine blade air seal flanges

A resurfacing machine and method for repairing turbine vanes and the like, the machine comprising a bed carrying a pair of supports which are capable of limited advancing and retracting movement with respect to one another. One of the supports is slidably carried on a pair of substantially parallel, coextensive guide bars mounted by the bed, and has a camming device engageable with a cam follower disposed on the other support. The latter is mounted for pivotal movement on the bed, and carries a motor driven sanding belt adapted to engage a workpiece clamped in place on a work-performing station of the first support. The movement of the first support is such that the workpiece is brought into engagement with the sanding belt as the support moves. Simultaneously, the cam follower is engaged by the cam, causing pivotal movement of the second support in such a way that the particular contour or shape of the cam is imparted to the workpiece. Means are provided for effecting automatic advancing and retracting movement of the first support on the bed, and for halting such movement when predetermined positions have been attained. Additional means are provided for adjusting the position of the cam with respect to the first support and workpiece, thus enabling variation in the degree of resurfacing of the particular vane being machined.

Machine for resurfacing turbine vanes

Disclosed is a machine for refinishing the side surfaces of air seal flanges which are located at the extremities of turbine blades and which have been resurfaced by welding. The machine comprises a pair of cutting belts arranged to have portions of their cutting surfaces juxtaposed and facing each other at a work-performing station, on a bench or table. The belts are power driven, and at the work-performing station pass between a pair of pivotally mounted pressure shoes which can be actuated by the machine operator to press against the back surfaces of the belts, so as to bring the belt cutting surfaces closer together. On the machine bench there is a movable slide, to which a turbine blade can be clamped in a manner to advance and place the built-up air seal flange thereof between the spaced-apart cutting belts at the work-performing station. A guide on the machine bench facilitates the positioning of the turbine blade seal between the belts. The pressure shoes are pivotally actuated by handles which are manipulated by the machine operator in a manner that the shoes can apply pressure to, and laterally shift the cutting belts against the opposite sides of the built-up air seal. This removes the excess metal from both sides of the seal simultaneously. Adjustable stops on the bench limit the extent of pivoting movement of the pressure shoes, and thus determine the amount of material which must be removed from the side surfaces of the seal flanges.

Turbine blade air seal, side grinder

A machine for refinishing edge portions of air seal flanges on the ends of turbine blades, comprising a bench or base, an abrasive belt carried by multiple pulleys mounted on the base, means for driving the belt, a contoured shoe carried by the base at a work-performing station thereon, and a slide movable over an upper surface of the base toward and away from the work-performing station, the slide being adapted to carry the turbine blade being refinished. Means are provided on the slide for releasably clamping the blade in a position such that the air seal flange thereof is movable toward and away from the cutting surface of the abrasive belt. The contoured shoe is disposed in a position wherein it backs up the belt at its point of contact with the air seal flange. In addition, adjustable stop means are provided on the base for limiting the advancing movement of the slide (and turbine blade) toward the belt, wherein the operator merely urges the slide slowly in one direction until the stop means become operative. Such an arrangement limits the amount of material which is ground from the air seal flange, and thus imparts a predetermined desired contour thereto. In addition, indicator means are provided, carried by the base, for enabling periodic measurements to be made of the remaining flange dimension. As a result, greatly improved resurfacing characteristics are realized, as well as a high degree of repeatability from one unit to another.

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North Branford, CT, United States of America

Ralph T DeMusis