Patent Publication Number: US-2015086408-A1

Title: Method of manufacturing a component and thermal management process

Description:
FIELD OF THE INVENTION 
     The present invention is directed to processes of manufacturing and thermal management processes using the manufactured component. More specifically, the present invention is directed to manufacturing processes for forming components that include cooling features formed therein. 
     BACKGROUND OF THE INVENTION 
     Turbine systems are continuously being modified to increase efficiency and decrease cost. One method for increasing the efficiency of a turbine system includes increasing the operating temperature of the turbine system. To increase the temperature, the turbine system must be constructed of materials able to withstand elevated temperatures during continued use. 
     In addition to modifying component materials and coatings, one common method of increasing temperature capability of a turbine component includes the use of cooling channels. The cooling channels are often incorporated into metals and alloys used in high temperature regions of gas turbines. Manufacturing cooling channels in components can be difficult and time-consuming. One technique includes casting the channels in the components using complex molds. The complex molds are often difficult to position relative to the component surface near the hot gas path where cooling is required. Another technique includes machining the channels into components after casting, which then requires closing the open channels off at the surface of the component by welding or brazing insert and impingement plates to the surface. The final component is then coated using thermal spraying. Closing the cooling channels can often inadvertently fill the cooling channels blocking the flow of cooling fluids, such as air from a compressor section of a gas turbine. 
     Selective laser melting (or three-dimensional printing) is a relatively inexpensive process capable of manufacturing difficult to fabricate components. However, components printed by selective laser melting do not have the same temperature capability as cast high temperature superalloy materials. Thus, use in high temperature environments has been perceived as ill-advised. 
     A method of forming a component and a thermal management process that do not suffer from one or more of the above drawbacks would be desirable in the art. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to an exemplary embodiment of the present disclosure, a method of forming a component is provided. The method includes forming at least one portion of the component, printing a cooling member of the component, and attaching the at least one portion to the cooling member of the component. The cooling member includes at least one cooling feature. The at least one cooling feature includes a cooling channel adjacent to a surface of the component, wherein printing allows for near-net shape geometry of the cooling member with the at least one cooling channel being located within a range of about 127 micrometers (0.005 inches) to about 762 micrometers (0.030 inches) from the surface of the component. 
     According to another exemplary embodiment of the present disclosure, a method of thermal management of a component is provided. The method includes forming at least one portion of the component, printing a cooling member of the component, attaching the at least one portion to the cooling member of the component, and transporting a fluid through at least one fluid pathway defined by the at least one cooling channel within the component to cool the component. The cooling member includes at least one cooling feature. The at least one cooling feature includes at least one cooling channel adjacent to a surface of the component. Printing allows for near-net shape geometry of the cooling member with the at least one cooling channel being located within a range of about 127 micrometers (0.005 inches) to about 762 micrometers (0.030 inches) from the surface of the component. The cooling channel defines a fluid pathway through which the fluid is transported. 
     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a component including a plurality of cooling channels formed therein, according to an embodiment of the disclosure. 
         FIG. 2  is a exploded perspective view of a cooling member of a component including cooling features. 
         FIG. 3  is a perspective view of a cooling member of a component including cooling features formed therein, according to an embodiment of the disclosure. 
         FIG. 4  is a cross-sectional view along line  4 - 4  of  FIG. 3  of the component, illustrating a cooling channel formed in the component, according to an embodiment of the disclosure. 
         FIG. 4  is a cross-sectional view along line  4 - 4  of  FIG. 2  of the component, illustrating at least one cooling channel including supply and exit passages, according to an embodiment of the disclosure. 
         FIG. 5  is a cross-sectional view along line  5 - 5  of  FIG. 3  of the component, illustrating cooling features formed in the component, according to an embodiment of the disclosure. 
         FIG. 6  is a cross-sectional view along line  6 - 6  of  FIG. 5  of a cooling channel formed in the component illustrating features that disrupt laminar flow of a fluid, according to an embodiment of the disclosure. 
     
    
    
     Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Provided is a manufacturing process and a thermal management process using the manufactured component. Embodiments of the present disclosure, in comparison to processes and articles that do not include one or more of the features disclosed herein, provide additional cooling and heating, permit cooling in new regions, permit cooling with new materials, permit cooler and/or hotter streams to be directed from flow within turbine components, permit the useful life of turbine components to be extended, permit turbine systems using embodiments of the turbine components to be more efficient, permit turbine components to be manufactured more easily, permit manufacturing of cooling features that previously could not be made, permit manufacturing of components that otherwise cannot be made using traditional manufacturing processes, permit hybrid material construction of turbine components or a combination thereof. 
     One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     The term “printing” refers to a three-dimensional printing process. Examples of three-dimensional printing processes include, but are not limited to, the processes known to those of ordinary skill in the art, such as Direct Metal Laser Melting (“DMLM”), Direct Metal Laser Sintering (“DMLS”), Selective Laser Sintering (“SLS”), Selective Laser Melting (“SLM”), and Electron Beam Melting (“EBM”). As used herein, the term “three-dimensional printing process” refers to the processes described above as well as other suitable current or future processes that include the build-up of materials layer by layer. 
     Referring to  FIG. 1 , in one embodiment, the component  100  may be a static component, rotating component or combustion hardware in a turbine system. Examples of static components include, but are not limited to, nozzles, vanes, shrouds, near flow path seals, transition pieces, and combinations thereof. Component  100  includes at least one portion  110  and a cooling member  120 . Cooling member  120  is attached to at least one portion  110  by any suitable joining technique, such as, but not limited to, brazing, welding or mechanical means. For example, in  FIG. 1 , component  100 , a nozzle, includes cooling member  120 , an airfoil, attached to a first end portion  114  and a second end portion  112 . 
     To manufacture component  100 , at least one portion  110  is formed. Suitable methods for forming at least one portion  110  include casting or printing. In one embodiment, at least one portion  110  is formed using traditional manufacturing methods, such as, but not limited to casting. At least one portion  110  may be cast using molds to form the desired shape using desired materials to provide desired strength and thermal characteristics. 
     Printing cooling member  120  or at least one portion  110  may include using three-dimensional printing to form at least one cooling feature  122  (see  FIGS. 2 and 5 ). The at least one cooling feature  122  includes cooling channels  130  and cooling cavities  490  and  590 . The at least one cooling channel  130  is adjacent to the surface  322  of component  100 . In an alternative embodiment, as shown in  FIG. 2 , a segment of cooling member  120  or portion  110  may be printed with at least one cooling channel  130 , then the printed segment of cooling member  120  or portion  110  including at least one cooling channel  130  is attached to other segments of cooling member  120  or portion  110 , without cooling channels. The other segment of cooling member  120  or portion  110  may be formed using methods such as, but not limited to, casting, forging, or printing. The three-dimensional printing includes distributing an atomized powder onto a substrate plate (not shown) using a coating mechanism (not shown). The substrate plate is positioned within a chamber (not shown) having a controlled atmosphere, for example, an inert gas, such as argon, nitrogen, other suitable inert gases, or a combination thereof. The atomized powder is melted, for example, by electron beam melting, laser melting, or other melting from other energy sources, to form a portion or layer of a three-dimensional product, such as, a segment of cooling member  120  or at least one portion  110  of a component  100 . The process is repeated to form the three-dimensional product, such as cooling member  120  or portion  110 . 
     Three-dimensional printing may use atomized powders that are thermoplastic, metal, metallic, ceramic, other suitable materials, or a combination thereof. Suitable materials for the atomized powder include, but are not limited to, stainless steel, tool steel, cobalt chrome, titanium, aluminum, alloys thereof, nickel based superalloys, or combinations thereof. In one embodiment, the material for the atomized powder corresponds with material for an alloy suitable for the hot-gas path of a turbine system. The material for cooling member  120  may be the same or different than material chosen for portion  110 . At least one portion  110  may be selected from a first material and cooling member  120  may be selected from a second material. In one embodiment, the first material may be different than the second material. Alternatively, the first material may be the same as the second material. Suitable examples of first material for at least one portion  110 , include, but are not limited to, nickel, iron, cobalt, chromium, molybdenum, aluminum, titanium, gold, silver, stainless steel, alloys thereof, nickel based superalloys, cobalt superalloys, or combinations thereof. Suitable examples of second material for cooling member  120 , include, but are not limited to, nickel, iron, cobalt, chromium, molybdenum, aluminum, titanium, gold, silver, stainless steel, alloys thereof, nickel based superalloys, cobalt superalloys, or combinations thereof. Suitable examples of commercially available materials, include, but are not limited to, Co—Cr (70Co, 27Cr, 3Mo), Stainless Steel 316, INCONEL® alloy 625 and INCONEL® alloy 718, INCONEL® alloy 738 (INCONEL® being available from Special Metals Corporation, Princeton, Ky.), GTD-222® (a trademark of General Electric Company), Haynes® 282® alloy (available from Haynes International, Kokomo, Ind.), UDIMET® alloy 500 (being available from Special Metals Corporation, Princeton, Ky.). In one embodiment, material for cooling member  120  may be chosen so as to have a higher thermal conductivity than the material from which at least one portion  110  is formed thereby enabling increased efficiency and requiring less fluid to be used to alter the temperature of surface  322  of component  100 . 
     One example of a three-dimensional printing process is selective laser melting which uses a predetermined design file or two-dimensional slices of a three-dimensional file, for example, from a computer-aided design program. The thickness of the two-dimensional slices determines the resolution of the selective laser melting. For example, when the two-dimensional slices are 20 micrometers thick, the resolution will be greater than when the two-dimensional slices are 100 micrometers thick for the printing of a predetermined component, such as, the cooling member  120 . In one embodiment, cooling member  120  or at least one portion  110  formed from the printing is near-net-shape and includes a plurality of cooling features  122  such as at least one cooling cavity  490 ,  590  and a plurality of cooling channels  130  formed therein. As shown in  FIG. 2 , cooling member  120  may be an airfoil, having near-net-shape and a plurality of cooling features  122  such as cooling cavities  490 ,  590  and cooling channels  130  formed therein. In one embodiment, cooling member  120  may be printed as a single piece (see  FIG. 1 ). In an alternative embodiment, as shown in  FIGS. 2 and 3 , cooling member  120  may be formed as a first segment  260  including a plurality of cooling channels  130  and at least one cooling cavity  490  and at least one second segment  280  optionally including a plurality of cooling cavities  590 . As shown in  FIGS. 2 and 3 , the at least one cooling cavity  490  of the first segment  260  may be aligned with the at least one cooling cavity  590  of the second cavity. The first segment  260  may be joined to the at least one second segment  280  using any suitable joining technique, shown by dashed lines  270  (see  FIG. 3 ). Printed cooling member  120  includes a first end  222  and a second end  224 . First end  222  or second end  224  may be attached to portion  110  using any suitable joining process, such as, but not limited to, brazing, welding or mechanical attachment means. As shown in  FIG. 1 , first end  222  of cooling member  120  is attached to first end portion  114  and second end  224  of cooling member  120  is attached to second end portion  112  by welding or brazing, illustrated by a joint  140 . Suitable examples of attaching include, but are not limited to, arc welding, beam welding, brazing, transient liquid phase (TLP) bonding, and diffusion bonding. 
     In one embodiment, as shown in  FIG. 1 , cooling member  120  is a single printed piece including cooling channels  130 , cooling cavities  490  and first openings  150  or supply passages and second openings  160  or exit passages formed therein. In an alternative embodiment, as shown in  FIGS. 2 and 3 , cooling member  120  is formed in steps. In one step, a first segment  260  including a plurality of cooling features  122  including cooling channels  130  and/or cooling cavities  490  and/or first and second openings  150  and  160  are printed. In another step, at least one second segment  280  is formed using three-dimensional printing or traditional casting techniques. As discussed above, first segment  260  may be formed using a first material and at least one second segment  280  may be formed using a second material. In one embodiment, first and second materials are the same. In an alternative embodiment, first and second materials are different. After first segment  260  and at least one second segment  280  are formed, cooling member  120  is built by joining first segment  260  and at least one second segment  280  along joint lines  270  (see  FIG. 3 ). Any suitable joining method may be used to join first segment  260  and at least one second segment  280 , such as, but not limited to, arc welding, beam welding, brazing, transient liquid phase (TLP) bonding, and diffusion bonding. 
     As shown in  FIG. 4 , first openings  150  of supply passages from cooling cavity  490  to cooling channel  130  and second openings  160  or exit passages for coolant to leave channel  130  may also be printed into cooling member  120  or first segment  260  of cooling member  120 . First openings  150  or inlets may be attached to cooling channel cavities  490  running throughout the length of component  100 . First openings  150  and second openings  160  are interconnected by cooling channels  130 . In one embodiment, second openings  160  may be cylindrical holes but could also be shaped holes to enable coolant exiting the cooling channel  130  to provide film coverage to the downstream portion of the component. Second openings  160  or exit passages may also be trenches where coolant from one or more cooling channels  130  enters to spread along the trench and then exit the trench as film (see  FIG. 1 ). 
     Referring to  FIG. 5 , using three-dimensional printing allows the at least one cooling channel  130  to be located at a distance  350  within a range of about 127 micrometers (0.005 inches) to about 762 micrometers (0.030 inches) from surface  322  of cooling member  120  of component  100 . Alternatively, three-dimensional printing allows the at least one cooling channel  130  to be located at a distance  350  of at least less than about  508  micrometers (0.020 inches) from the surface  322  of cooling member  120  of component  100  (see  FIG. 5 ). Distance  350  between cooling channel  130  and surface  322  of component  100  may be up to at least less than or as little as about 127 micrometers (0.005 inches). Distance  350  between cooling channel  130  and surface  322  of component  100  may be constant throughout cooling channel  130  length in component  100 . In an alternative embodiment, distance  350  may be varied throughout length of cooling channel  130  in component  100  (see  FIG. 4 ). Distance  350  may be from about 127 micrometers (0.005 inches) to about 1524 micrometers (0.060 inches), or alternatively about 254 micrometers (0.010 inches) to about 1270 micrometers, or alternatively about 254 micrometers (0.010 inches) to about 1016 micrometers, or alternatively about 254 micrometers (0.010 inches) to about 508 micrometers (0.020 inches), or alternatively less than about 508 micrometers (0.020 inches), or alternatively about 254 micrometers (0.010 inches) or alternatively about 127 micrometers (0.005 inches). In comparison, typical casting methods used to form a component with cooling channels will have cooling channels located at about 2540 micrometers (0.100 inches) from surface. 
     Using three-dimensional printing to form at least one cooling channel  130  in cooling member  120  or at least one portion  110  reduces manufacturing steps and saves time and resources because cooling channels do not need to be drilled into the surface of component. Printing cooling member  120  or at least one portion  110  with cooling channels  130  formed therein also reduces manufacturing steps and time and resources because open cooling channels do not need to be closed using insert plates. The three-dimensional printing processes also allows the geometry (length, width, height, and depth) of the cooling channels  130  and at least one fluid pathway  360  therein to be varied along the length of cooling channel  130  within cooling member  120 . For example, cooling channel  130  may constrict or narrow in some areas or widen in other areas to match the cooling or heating local demands of component  100 . Cooling channel  130  dimensions may be changed as necessary and the dimensions do not need to be constant from one end to another. In one embodiment, cooling channel  130  may be a semi-circle having a width and depth of about 254 micrometers (0.010 inches) to about 2540 micrometers (0,100 inches) or alternatively about 762 micrometers (0.030 inches) to about 1524 micrometers (0.060 inches). 
     In one embodiment, prior to joining cooling member  120  to at least one portion  110 , an optional step of hot isostatic pressing (HIP) and/or solution heat-treating is performed to strengthen the printed cooling member  120  or at least one portion  110 . During HIP operation, internal defects such as porosity and microfissures are closed or healed due to the temperature and applied pressure. During solution heat treatment, all deleterious precipitates are put into solution in the material matrix thereby providing the best properties. These heat treatments change the grain structure through formation of new grains ultimately strengthening the printed cooling member  120 . 
     As shown in  FIG. 4 , surface  322  may be coated with a protective coating  340 . Protective coating  340  may include any number of layers, such as, but not limited to a bond coating  342  and thermal barrier coating  344  applied to bond coating  342 . Protective coating  340  may be applied prior to joining cooling member  120  to at least one portion  110 . Protective coating  340  may be applied after cooling member  120  is jointed to at least one portion  110  by welding, brazing or other suitable mechanical joining means. 
     Transporting a fluid through at least one fluid pathway  360  defined by at least one cooling channel  130  within the component alters, cools, or heats surface  322  of component  100 . The changes in geometry may be designed so as to maximize or minimize the alteration of temperature at any particular location along the length of at least one cooling channel  130  in component  100 . The changes in geometry may enable highly specific manipulation of the thermal characteristics of surface  322  by at least one cooling channel  130 . The geometry changes may enable the modification of thermal management properties of a component design with minimized cost and time compared to methods and articles that do not include one or more of the features disclosed herein. 
     Referring to  FIG. 6 , in one embodiment, at least one cooling channel  130  may include at least one feature to disrupt laminar flow of a fluid through the at least one fluid pathway  360 . The at least one feature to disrupt laminar flow may include turbulators  406 , which mix the fluid in the at least one fluid pathway  360  from the middle to the sides and from the sides to the middle, making the at least one fluid pathway  360  effectively longer. Turbulators  406  may also increase the surface area of at least one cooling channel  130 , which increases heat transfer from or to the fluid flowing through the at least one fluid pathway  360  to or from the substrate  322 . Suitable examples of turbulators  406  include, but are not limited to, fin  410  and bumps  412 . Turbulators  406  may be of any suitable shape or size, and may be included on the at least one inner surface of cooling channel  130  in any suitable arrangement or spacing to achieve the desired effect. Turbulators  406  may be formed within at least one cooling channel  130  using a three-dimensional printing process, resulting in a single homogeneous piece. 
     Also provided is a method of thermal management. The method includes forming at least one portion  110  of component  100  (see  FIG. 1 ). The method includes printing a cooling member  120  (see  FIG. 1 ) or first segment  260  and at least one second segment  280  and building cooling member  120  of component  100  (see  FIGS. 2 and 3 ). The method includes attaching the at least one portion  110  to cooling member  120  of component  100  (see  FIG. 1 ). The method includes transporting a fluid through the at least one fluid pathway  360  defined by the at least one cooling channel  130  within component  100  to cool component  100  (see  FIGS. 4 and 6 ). 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.