Variable polarity arc technology for the repair of coated articles
AssigneeUnited Technologies Corporation
InventorsPeter Wrabel, Peter Jon Draghi
Life of this patent
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Abstract
Variable polarity welding is used to repair coated articles, particularly gas turbine engine components. The variable polarity welding process is found to remove the coating during the welding process. This permits the elimination of costly steps which would otherwise be needed in the repair process.
Claims12
In the method of weld repairing a superalloy substrate having on its surface a protective coating selected from the groups consisting essentially of aluminide coatings, overlay coatings, ceramic thermal barrier coatings, and combinations thereof, the improvement which comprises:
- using a variable polarity welding system whereby the protective coating is removed as a part of the welding process.
A method of removing a protective surface coating selected from the group consisting of aluminide and overlay coatings and combinations thereof, from a superalloy substrate, which comprises using a variable polarity welding power supply and striking an arc between said coated superalloy substrate and an electrode, to form a localized molten region in said superalloy substrate, wherein the arc is DCEN for 70-90% of the variable polarity current cycle and DCEP for the balance of said cycle, the current is between about 5 and 50 amperes and the frequency of the variable polarity cycle is from 10 to 1000 Hz.
Dependencies are inferred from the claim text.