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Publication Date: 2015-Feb-13
Document File: 25 page(s) / 2M

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The Prior Art Database


The present disclosure is related to improvements to the solid state resistance welding process used to repair airfoils.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 17% of the total text.

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    The present disclosure is related to improvements to the solid state resistance welding process used to repair airfoils.


    Gas turbine engines generally include a compressor for compressing air, which is mixed with a fuel and channeled to a combustor wherein the mixture is ignited within a combustion chamber for generating hot combustion gases. The hot combustion gases are channeled downstream to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight or to power a load, such as an electrical generator.

    There are multiple components of jet engines that comprise a rotor assembly that includes at least one row of circumferentially spaced rotor blades. Each rotor blade includes an airfoil that includes a pressure side and a suction side extending between leading and trailing edges. Each airfoil extends radially outward from a rotor blade platform, disk, or drum. In at least some known compressors, the rotor blade is formed integrally with the rotor disk or drum and the assembly is often referred to as a bladed disk or a bladed drum. Fan, compressor, and other gas turbine engine rotors may have a bladed disk or a bladed drum.

    During engine operation, leading and trailing edges of the blade and/or a tip of the compressor blade airfoil may deteriorate or become damaged due to any of a number of distress modes, including, but not limited to, foreign object damage (FOD), tip rubbing, oxidation,




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thermal fatigue cracking, or erosion caused by abrasives and corrosives in the flowing gas stream. To facilitate mitigating such operational effects, the blades are periodically inspected for damage, and a determination of an amount of damage and/or deterioration is made. If the blades have lost a substantial quantity of material, they are replaced. If the blades have only lost a small quantity material, they may be returned to service without repair. Alternatively, if the blades have lost an intermediate quantity of material, the blade airfoils may be repaired.

    One new proposed way to repair the blades is to cut or grind off the tip of the airfoil that includes the damaged section to remove it and then attach a new tip to the base of the old one to take the place of the removed tip. One way to attach the new tip to the original stub is to use solid state resistance welding (SSRW), which is a welding technique used that avoids melting the metal so that the repaired airfoil can have maximum mechanical strength.

    This method involves fitting electrodes to each side of the part that is to be welded and using an electrical current that generates heat at the interface of the two parts due to the resistance provided at the interface. At the interface, when the metals are forced together with a relatively large amount of force, parts of the metals from th...