COMPOSITE TURBOMACHINE COMPONENT AND RELATED METHODS OF MANUFACTURE AND REPAIR

Various aspects include a composite turbomachine component and related methods. In some cases, a method includes: identifying a location of potential or actual structural weakness in a body of a turbomachine component, the body including a first material having a first thermal expansion coefficient; forming a slot in the location of the body, the slot extending at least partially through a wall of the turbomachine component; and bonding an insert to the body at the slot to form a composite component, the insert including a second material having a second thermal expansion coefficient differing from the first thermal expansion coefficient by up to approximately ten percent, the second material consisting of a nickel-chromium-molybdenum alloy, wherein after the bonding the insert is configured to reduce the potential or actual structural weakness in the body.

FIELD OF THE INVENTION

The subject matter disclosed herein relates to manufacturing and repair of components. More specifically, the subject matter disclosed herein relates to approaches of manufacturing and/or repairing components to manage material stress.

BACKGROUND OF THE INVENTION

During operation, turbomachine components, such as turbomachine blades and nozzles, are subjected to high temperatures, pressures and/or stresses over extended periods. In many cases, particular portions of these components can be subject to differential stresses due to their geometry and location relative to a working fluid (e.g., gas or steam). For example, a blade platform or tip, or a nozzle sidewall, can be subject to different warmup and cool down rates than the airfoil of that same blade or nozzle. This differential thermal inertia can cause tensile stress at or near the platform and/or tip (or sidewall). These tensile stresses may contribute to cracking or other material fatigue, and ultimately can require repair and/or maintenance.

BRIEF DESCRIPTION OF THE INVENTION

Various aspects of the disclosure include a composite turbomachine component and methods of forming such a component. In a first aspect, a method includes: identifying a location of potential or actual structural weakness in a body of a turbomachine component, the body including a first material having a first thermal expansion coefficient; forming a slot in the location of the body, the slot extending at least partially through a wall of the turbomachine component; and bonding an insert to the body at the slot to form a composite component, the insert including a second material having a second thermal expansion coefficient, the second thermal expansion coefficient differing from the first thermal expansion coefficient by up to approximately ten percent, the second material consisting of a nickel-chrome-molybdenum alloy, wherein after the bonding the insert is configured to reduce the potential or actual structural weakness in the body.

A second aspect of the disclosure includes a composite turbomachine component having: a body including: a wall; and a slot extending at least partially through the wall, wherein the body includes a first material having a first thermal expansion coefficient, the first material including at least one of: steel, at least one nickel-chromium superalloy, at least one cobalt-based superalloy or at least one nickel-based superalloy; an insert substantially filling the slot, the insert including a second material having a second thermal expansion coefficient, the second thermal expansion differing from the first thermal expansion coefficient by up to approximately ten percent, the second material consisting of a nickel-chromium-molybdenum alloy; and a weld or braze joint coupling the insert to the body at the slot.

DETAILED DESCRIPTION OF THE INVENTION

The subject matter disclosed herein relates to manufacturing and/or repair. More specifically, the subject matter disclosed herein relates to composite components with materials of distinct thermal expansion coefficients, and methods of forming those components.

In contrast to conventional approaches, various aspects of the disclosure include a composite turbomachine component, and methods of forming such a component. In various embodiments, the composite turbomachine component has a body and an insert filling a slot in the body, where the location of the slot is determined based upon an expected or actual amount of material fatigue in that portion of the body. The insert can be welded to the body at the slot, but in some cases, the insert could also be brazed to the body at the slot. In various embodiments, the body of the turbomachine component is formed of steel or an alloy, such as at least one nickel-chromium superalloy, at least one cobalt-based superalloy or at least one nickel-based superalloy (e.g., Inconel-738, Inconel-939, Udimet 500 and Udimet 700, from Special Metals Corp., New Hartford, N.Y.; or GTD-111, GTD-222, GTD-241, GTD-741 or GTD-141 (from the General Electric Company, Boston, Mass.); or FSX-414). In various embodiments, the insert can include a material having a distinct thermal expansion coefficient from the material of the body, e.g., approximately 0.9 to approximately 1.1 times the thermal expansion coefficient of the body. In some cases, the insert can include a nickel-chromium-molybdenum alloy (e.g., Nimonic 263, from the Special Metals Corp or Haynes 230, from Haynes International, Inc., Kokomo, Ind.), and in some particular cases, the insert can consist substantially entirely (e.g., given nominal other materials) of a nickel-chromium-molybdenum alloy. The location of the slot (and insert) is determined based upon a model (e.g., a finite element analysis model) of the turbomachine component, or an observed wear on the turbomachine component (e.g., via human operator inspection, or with an optical inspection system, florescent inspection system, infra-red inspection system). The slot (and insert) may be located within a portion of the platform, in the case of a turbomachine blade, or a sidewall, in the case of a turbomachine nozzle. In some other cases, the slot (and insert) can be located proximate the tip of the airfoil, e.g., in a “Z-notch” region of the blade. The composite turbomachine component may be stronger than conventional turbomachine components formed of a uniform or substantially uniform material composition.

In some particular cases, the slot is machined from the body, e.g., by cutting, sanding or otherwise abraded the location in the body for the insert. After the insert is placed in the slot, it may be welded, brazed or otherwise heat-treated to bond with the body and fill the slot. After bonding the insert to the body at the slot, the surface of the insert and the body may be machined, e.g., grinded, sanded, or otherwise planarized to form a surface profile consistent with the original design of the blade.

In various embodiments, the composite component can include a refurbished component, e.g., where the body is an original part having gone through field use and the insert is a replacement portion of the component. In other cases, the composite component can include two original parts (either having gone through field use, or not) joined at an interface, and in other cases, the composite component can include two replacement parts joined at an interface.

FIG. 1shows an example set of turbomachine components2. In some cases, turbomachine component2can include a gas turbomachine blade10. However, as discussed herein, turbomachine component2can include turbine nozzles, guide vanes, etc., subject to high thermal stresses during operation. As shown, in some cases, a plurality of turbomachine components2(e.g., blades10) can be coupled with a turbomachine disc14(rotor disc), forming part of a turbine stage12. Each blade10can include a platform16, an airfoil18connected with and radially extending from platform16, and a shroud20connected airfoil18. Platform16is coupled with base22of airfoil18, and shroud20is coupled with tip24of airfoil18. Adjacent shrouds20in a stage12can include complementary interfaces, also referred to as a Z-notch25, for linking the blades10in the same stage12.

FIG. 2illustrates a first process in a method of forming a composite turbomachine component according to various embodiments of the disclosure.FIGS. 3 and 4show close-up schematic depictions of a portion of a turbomachine component2(such as blade10, a nozzle, a guide vane, or other turbomachine component), undergoing additional processes in forming a composite turbomachine component410(FIG. 4) according to embodiments of the disclosure.FIG. 5is a flow diagram illustrating processes shown and described with reference toFIGS. 2-4.

With reference toFIGS. 2-5, according to various embodiments, a method can include:

Process P1: identifying a location100of potential or actual structural weakness in a body110of turbomachine component2. In various embodiments, body110includes a first material having a first thermal expansion coefficient. That is, in some cases, body110of component2is composed entirely, or approximately (e.g., within 1-3 percent) entirely of, a first material, which has a first thermal expansion coefficient. In some cases, the first material includes steel. It is understood that the first material or second material may include impurities to the extent acceptable in conventional turbomachine components. In some particular cases, the first material can include a steel or an alloy such as at least one nickel-chromium superalloy, at least one cobalt-based superalloy or at least one nickel-based superalloy (e.g., Inconel-738, Inconel-939, Udimet 500 and Udimet 700, from Special Metals Corp., New Hartford, N.Y.; or GTD-111, GTD-222, GTD-241, GTD-741 or GTD-141 (from the General Electric Company, Boston, Mass.); or FSX-414). In various embodiments, the thermal expansion coefficient of the first material (at an example temperature of approximately 815 degrees Celsius (1500 degrees Fahrenheit)) is approximately 8×10−5in/(in F). The location100of potential or actual structural weakness in body110can be identified according to various embodiments. In some cases, location100can be identified by a user120, e.g., a user such as a human user, robotic user or other machine. In some cases, user120can include, or work in conjunction with, an inspection system130for analyzing turbomachine component2to detect one or more location(s)100of potential or actual structural weakness. In some cases, inspection system130can include at least one of an optical scanner, an infrared scanner or a fluorescent inspection system. Inspection system130can include conventional scanning/inspection components such as laser-based detection components, infrared sensors, transmitters, receivers, transducers, etc. Where user120is a human user, that human user may visually inspect turbomachine component2to detect one or more location(s)100of potential or actual structural weakness. It is understood that user120and/or inspection system130may be particularly useful in detecting location(s)100of actual structural weakness, e.g., locations of visible or physically detectable cracks, deformations, material fatigue, etc. In some particular cases, a user120(e.g., human user) can use an inspection system130, such as a fluorescent inspection system or a blue-light scanner to visually inspect component2to detect one or more locations100of structural weakness.

In some other embodiments, identifying location(s)100can include performing a finite element analysis on a data file140representing turbomachine component2. In these embodiments, data file140can include a computer-aided design (CAD) file or other data model representing turbomachine component2. In some cases, data file140can be used to form turbomachine component2or another similar component. In various embodiments, a turbomachine component analysis system (analysis system)150can be used to analyze data file140to identify location(s)100in turbomachine component2of potential or actual structural weakness. In particular cases, turbomachine analysis system150can be configured to identify locations(s)100of potential structural weakness in turbomachine component2, e.g., based upon a modeled response of turbomachine component2to expected operating conditions such as particular temperature ranges, pressure ranges, fatigue cycles, warmup/cooldown cycles, etc. In various embodiments, turbomachine component analysis system150can be stored or otherwise deployed by a conventional computer system200having a processor (PU)210, memory220, storage device230and an input/output (I/O) device240. Turbomachine component analysis system150can include one or more logic engines (or modules)250for executing commands to analyze data file140according to various embodiments described herein. In particular cases, data file140can include a three-dimensional (3D) model of the component2, and analysis system150can include a software program for analyzing low-cycle fatigue and/or crack propagation in the 3D model, such as conventional simulation software (e.g., ANSYS Mechanical, from ANSYS, Inc., Canonsburg, Pa.).

According to various embodiments, where turbomachine component2includes a blade10, location100may be within platform16or tip shroud20, proximate airfoil18.FIG. 2illustrates several locations100, within platform16and tip shroud20, which shown in phantom to demonstrate that one or more locations100can be identified according to various embodiments. In some particular cases, location100can be proximate the aft (downstream) side of platform16, for example, at the suction side of airfoil18.

Process P2: after identifying location100, according to various embodiments, the process can further include forming a slot300(FIG. 3) in location100of body110, where slot300extends at least partially through a wall310of turbomachine component2. In some cases, slot300can be formed by cutting turbomachine component2proximate location100. In various embodiments, as shown inFIG. 3, slot300can be formed in an area substantially surrounding location100(e.g., at border of location100or slightly outside the border of location100). In some embodiments, turbomachine component2can include an original equipment component not yet deployed in operation. In some particular cases, forming slot300in body110includes cutting or otherwise machining turbomachine component2, e.g., with a saw or other machining tool. In other cases, turbomachine component2can be formed as an original component, including slot300, via conventional molding, casting, etc., or via additive manufacturing techniques further described herein.

Process P3: after forming slot300in component2, bonding an insert400(FIG. 4) to body100at the slot300to form a composite component410. In various embodiments, insert400includes a second material (distinct from first material of body100), having a second thermal expansion coefficient. The second thermal expansion coefficient can differ from the first thermal expansion coefficient by approximately +/−10 percent (e.g., approximately between 0.9-1.1 times the first thermal expansion coefficient of body100material). In some cases, insert can consist of, or substantially (e.g., 95% or greater) consist of the second material, which can include at least one nickel-chromium-molybdenum alloy (e.g., Nimonic 263, from the Special Metals Corp or Haynes 230, from Haynes International, Inc., Kokomo, Ind.), and in some particular cases, the insert can consist substantially entirely (e.g., given nominal other materials) of a nickel-chromium-molybdenum alloy. According to various embodiments, insert400is welded to body110at slot300according to conventional welding techniques. In some other cases, insert400is brazed to body110at slot300according to conventional welding techniques. In either case, insert400is bonded to body110with a weld or braze joint420. In some cases, welding can be used to bond insert400to body110at slot, e.g., at a current of approximately 40-50 Amperes, with an arc voltage of approximately 10-15 volts. As noted herein, after bonding to body110, insert400is configured to reduce the potential or actual structural weakness in body110.

Process P4(optional post-process): in some cases, after bonding insert400to body110of component2, an additional process can include planarizing an outer surface430of body110and insert400proximate slot300. In various embodiments, planarizing can include conventional machining processes such as sanding, grinding, polishing or otherwise smoothing outer surface430of body110and insert400proximate slot300.

As shown inFIG. 4, processes P1-P3(and optionally process P4), can be used to form composite turbomachine component410which is configured to reduce potential or actual structural weakness in a turbomachine component2. That is, according to various embodiments, turbomachine component410is designed to include insert400at a strategically placed location100in order to reduce actual or potential structural weakness in the base turbomachine component2.

It is understood that the processes described herein can be performed in any order, and that some processes may be omitted, without departing from the spirit of the disclosure described herein.

One or more portions of composite component410(FIG. 4) may be formed in a number of ways. In one embodiment, as noted herein, at least a portion of composite component410may be formed by conventional manufacturing techniques, such as molding, casting, machining (e.g., cutting), etc. In one embodiment, however, additive manufacturing is particularly suited for manufacturing at least a portion of composite component410(FIG. 4), e.g., turbomachine component2and/or insert400. As used herein, additive manufacturing (AM) may include any process of producing an object through the successive layering of material rather than the removal of material, which is the case with conventional processes. Additive manufacturing can create complex geometries without the use of any sort of tools, molds or fixtures, and with little or no waste material. Instead of machining components from solid billets of metal (e.g., alloy) or other material such as plastics and/or polymers, much of which is cut away and discarded, the only material used in additive manufacturing is what is required to shape the part. Additive manufacturing processes may include but are not limited to: 3D printing, rapid prototyping (RP), direct digital manufacturing (DDM), selective laser melting (SLM) and direct metal laser melting (DMLM). In the current setting, DMLM can be beneficial.

To illustrate an example of an additive manufacturing process,FIG. 6shows a schematic/block view of an illustrative computerized additive manufacturing system900for generating an object902. In this example, system900is arranged for DMLM. It is understood that the general teachings of the disclosure are equally applicable to other forms of additive manufacturing. Object902is illustrated as a double walled turbomachine component; however, it is understood that the additive manufacturing process can be readily adapted to manufacture at least a portion of composite component410(FIG. 4), e.g., turbomachine component2and/or insert400. AM system900generally includes a computerized additive manufacturing (AM) control system904and an AM printer906. AM system900, as will be described, executes code920that includes a set of computer-executable instructions defining at least a portion of composite component410(FIG. 4) to physically generate the object using AM printer906. Each AM process may use different raw materials in the form of, for example, fine-grain powder, liquid (e.g., polymers), sheet, etc., a stock of which may be held in a chamber910of AM printer906. In the instant case, at least a portion of composite component410(FIG. 4) may be made of metal(s), alloy(s), plastic/polymers or similar materials. As illustrated, an applicator912may create a thin layer of raw material914spread out as the blank canvas from which each successive slice of the final object will be created. In other cases, applicator912may directly apply or print the next layer onto a previous layer as defined by code920, e.g., where the material is a polymer. In the example shown, a laser or electron beam916fuses particles for each slice, as defined by code920, but this may not be necessary where a quick setting liquid plastic/polymer is employed. Various parts of AM printer906may move to accommodate the addition of each new layer, e.g., a build platform918may lower and/or chamber910and/or applicator912may rise after each layer.

AM control system904is shown implemented on computer930as computer program code. To this extent, computer930is shown including a memory932, a processor934, an input/output (I/O) interface936, and a bus938. Further, computer930is shown in communication with an external I/O device/resource940and a storage system942. In general, processor934executes computer program code, such as AM control system904, that is stored in memory932and/or storage system942under instructions from code920representative of at least a portion of composite component410(FIG. 4), described herein. While executing computer program code, processor934can read and/or write data to/from memory932, storage system942, I/O device940and/or AM printer906. Bus938provides a communication link between each of the components in computer930, and I/O device940can comprise any device that enables a user to interact with computer940(e.g., keyboard, pointing device, display, etc.). Computer930is only representative of various possible combinations of hardware and software. For example, processor934may comprise a single processing unit, or be distributed across one or more processing units in one or more locations, e.g., on a client and server. Similarly, memory932and/or storage system942may reside at one or more physical locations. Memory932and/or storage system942can comprise any combination of various types of non-transitory computer readable storage medium including magnetic media, optical media, random access memory (RAM), read only memory (ROM), etc. Computer930can comprise any type of computing device such as a network server, a desktop computer, a laptop, a handheld device, a mobile phone, a pager, a personal data assistant, etc.

Additive manufacturing processes begin with a non-transitory computer readable storage medium (e.g., memory932, storage system942, etc.) storing code920representative of at least a portion of composite component410(FIG. 4). As noted, code920includes a set of computer-executable instructions defining outer electrode that can be used to physically generate the tip, upon execution of the code by system900. For example, code920may include a precisely defined 3D model of outer electrode and can be generated from any of a large variety of well-known computer aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3D Max, etc. In this regard, code920can take any now known or later developed file format. For example, code920may be in the Standard Tessellation Language (STL) which was created for stereolithography CAD programs of 3D Systems, or an additive manufacturing file (AMF), which is an American Society of Mechanical Engineers (ASME) standard that is an extensible markup-language (XML) based format designed to allow any CAD software to describe the shape and composition of any three-dimensional object to be fabricated on any AM printer. Code920may be translated between different formats, converted into a set of data signals and transmitted, received as a set of data signals and converted to code, stored, etc., as necessary. Code920may be an input to system900and may come from a part designer, an intellectual property (IP) provider, a design company, the operator or owner of system900, or from other sources. In any event, AM control system904executes code920, dividing at least a portion of composite component410(FIG. 4) into a series of thin slices that it assembles using AM printer906in successive layers of liquid, powder, sheet or other material. In the DMLM example, each layer is melted to the exact geometry defined by code920and fused to the preceding layer. Subsequently, the portion(s) of composite component410(FIG. 4) may be exposed to any variety of finishing processes, e.g., minor machining, sealing, polishing, assembly to other part of the igniter tip, etc.