Patent Application
20090271984
This disclosure relates to a method for repairing a worn surface of a gas turbine engine component.
Gas turbine engines typically include a compressor section, a combustor section and a turbine section. Air is pressurized in the compressor section, and is mixed with fuel and burned in the combustor section to energize and expand the air and accelerate the airflow into the turbine section. The hot combustion gases that exit the combustor section flow downstream through the turbine section, which extracts kinetic energy from the expanding gases and converts the energy into mechanical power to drive the compressor section.
The compressor section of the gas turbine engine typically includes multiple compression stages to obtain high pressure levels. Each compressor stage consists of alternating rows of stator assemblies that include stationary airfoils called stator vanes followed by rotor assemblies including moving airfoils called rotor blades. The stator vanes direct incoming airflow to the next set of rotor blades.
During operation, portions of the stator assemblies may become worn as a result of rubbing that occurs between the stator assemblies and surrounding components of the gas turbine engine. The rubbing may wear and stress portions of the stator assemblies.
Replacing an entire stator assembly is expensive due to material and machining costs. Accordingly, stator assemblies are often repaired instead of replaced. The repairs generally involve removing the worn surfaces of the stator assembly, and then restoring them with weld filler or similar material on a surface of the component. The material build-up is machined to an appropriate shape to form a restored surface.
A known gas tungsten arc (GTA) welding process is generally used to repair worn surfaces of gas turbine engine components. The GTA welding process may be performed manually or robotically to deposit weld material on a worn area of the component. However, GTA welding is a relatively slow build-up process that, because of the inherent heat input, can cause unacceptable component distortion. These aspects have prompted the aerospace industry to seek faster and less heat intensive welding processes.
A method of repairing a stator assembly of a gas turbine engine includes removing a worn surface of the stator assembly to provide a revealed area, and securing additional material to the stator assembly utilizing gas metal arc welding.
A gas turbine engine component includes a stator assembly having at least one repairable surface. The stator includes a repaired section. Additional material is deposited on the at least one repairable surface to fabricate the repaired section using gas metal arc welding.
The various features of the example disclosure can be best understood from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
The low pressure compressor 14 and the high pressure compressor 16 include a plurality of alternating rows of rotor assemblies 24 having blades 26 and stator assemblies 28 including vanes 30. It should be understood that the various features and example illustrations presented herein are not limited to a gas turbine engine of this particular architecture. That is, the present disclosure is applicable to any engine architecture, and for any application.
The worn surfaces 32 may occur at any location of the stator assembly 28, including but not limited to, the flange 36, the outer diameter surface 38 and/or the featherseal slot 40. In one example, the worn surface 32 includes a crack in the outer diameter surface 38. The worn surfaces 32 may be caused by the rubbing, vibration and/or extreme temperatures that occur during gas turbine engine 10 operation. The worn surfaces 32 are repairable utilizing a gas metal arc welding operation, as is further discussed below. Although the disclosed examples are illustrated with respect to a stator assembly 28 of a high pressure compressor 16, it should be understood that the disclosed examples may be applied to any gas turbine engine component.
Next, at step block 104, additional material is secured to the gas turbine engine component 15 utilizing gas metal arc welding. In one example, the gas metal arc welding includes cold metal transfer. Cold metal transfer is a process developed by the Fronius Corporation and is known. However, gas metal arc welding has not been utilized to repair a worn surface of a gas turbine engine component 15, such as a stator assembly 28 of a high pressure compressor 16, for example. The additional material is secured to the gas turbine engine component 15 in an area of the removed worn surface 32.
At step block 106, a portion of the additional material is removed from the gas turbine engine component 15. In one example, the portion of the additional material is removed via a machining operation. The additional material is removed down to a pre-defined dimension. In one example, the predefined dimension includes an original dimension of the gas turbine engine component.
As shown in
The example gas metal arc welding operation of the present disclosure facilitates a low heat input, high deposition, and spatter free weld process for repairing worn surfaces of a gas turbine engine component. For example, the gas metal arc welding operation may be utilized to repair a worn surface of a stator assembly of a gas turbine engine.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications would come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.
