Method of Making a Combustion Turbine Component from Metallic Combustion Turbine Subcomponent Greenbodies

Abstract

A method of making a combustion turbine component includes assembling a plurality of metallic combustion turbine subcomponent greenbodies together to form a metallic greenbody assembly and sintering the metallic greenbody assembly to thereby form the combustion turbine component. Each of the plurality of metallic combustion turbine subcomponent greenbodies may be formed by direct metal fabrication (DMF). In addition, each of plurality of metallic combustion turbine subcomponent greenbodies may include an activatable binder and the activatable binder may be activated prior to sintering.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of the filing date of U.S. Provisional Patent, Ser. No. 61 / 022,952, filed on Jan. 23, 2008.GOVERNMENT CONTRACT[0002]The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of contract No. DE-FC26-05NT42644 awarded by the Department of Energy.FIELD OF THE INVENTION[0003]The present invention relates to the field of metallurgy, and, more particularly, to methods of making a combustion turbine component from a plurality of metallic combustion turbine subcomponent greenbodies.BACKGROUND OF THE INVENTION[0004]A combustion turbine typically includes, in a serial flow relationship, a compressor section to compress the entering airflow, a combustion section in which a mixture of fuel and the compressed air is burned to generate a propulsive gas flow, and a turbine section tha...

AI Technical Summary

Benefits of technology

[0017]This and other objects, features, and advantages in accordance with the present invention are provided by a method of making a combustion turbine component that may comprise assembling a plurality of metallic combustion turbine subcomponent greenbodies together to form a metallic greenbody assembly, and sintering the metallic greenbody assembly to thereby form the combustion turbine component. The assembling and sintering of the plurality of metallic combustion turbine subcomponent greenbodies to form the combustion turbine component may provide for better tolerance and shrinkage control of the resulting combustion turbine component than possible if finished combustion turbine subcomponents were assembled and joined together. In addition, this method advantageously provides a stronger bond between the plurality of metallic combustion turbine subcomponent greenbodies.

[0018]Each of the plurality of metallic combustion turbine subcomponent greenbodies may be formed by direct metal fabrication (DMF). The DMF may comprise tomo lithographic molding. The DMF may also comprise metal injection molding. DMF advantageously allows for a greater variety of shapes to be formed than casting or forging. In addition, DMF allows the formation of smaller surface features than may be possible with conventional casting or forging processes.

[0022]At least one of the plurality of metallic combustion turbine subcomponent greenbodies may be formed to have a plurality of surface features, each with a dimension less than 200 μm. These surface features may provide the combustion turbine component with enhanced heat dissipation properties and high temperature resistance by increasing the surface area thereof. A large number of such small surface features may increase the surface area beyond what would be possible with larger surface features alone.

Problems solved by technology

There may, however, be limitations on the size of the combustion turbine components that may be formed by casting.

Likewise, there may be limitations on the size of surface features of the combustion turbine components that may be formed (e.g. it may not be possible to form surface features having dimensions below a certain size).

However, due to the fine grain structure, a forged combustion turbine component generally exhibits relatively low resistance to creep and may thus be unsuitable for use in certain applications Subsequent heat treatment can promote grain growth, however, and it is may be easier to control grain size in a forging than a casting.

In addition, the formation of small surface features on such a combustion turbine component during the forging process may be difficult.

Since forgings are generally solid shapes and cooling passages are later machined into the forging, it may be difficult to machine fine scale internal features on an internal surface of a cooling passage of a forging.

As discussed above, due to process limitations and cost concerns, forming an entire combustion turbine component of a desired shape and having desired surface features by the above processes may be difficult or costly.

However, some features may not be easily or cost effectively formed by casting or forging processes.

In addition, some combustion turbine subcomponents may be constructed from materials that are not easily friction stir welded.

However, a braze joint may be undesirable in some situations and may not provide as strong a bond as desired.

However, a combustion turbine component formed by casting and having an increased surface area may not be desirable in some applications.

Furthermore, certain arrangements of surface cooling features may not be easily formed by casting techniques.

However, recessed grooves may not provide the desired cooling capabilities in some applications.

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