Imported: 24 Feb '17 | Published: 09 Apr '02
USPTO - Utility Patents
A method is provided for treating cooperating, juxtaposed substantially uncoated alloy substrate surfaces in preparation for brazing, for example an inner wall of the radially outer open end of a turbine engine blading member with the rim of an end plate or tip cap. The method includes treating at least one of the cooperating surfaces with a reducing gas comprising halogen gas for a time and at a temperature, for example 1-6 hours at 1650-1950° F., sufficient to remove any surface debris, for example oxides, and to deplete the alloy substrate surface of the total of elements selected from Al and Ti to a level of less than about 1 weight %. Depletion is to a depth in the surface which avoids intergranular attack of the substrate alloy surface. For example, the depth is no greater than about 0.0015″. Then the cooperating surfaces are brazed together.
1. In a method for making an article comprising a body including a brazed joint between juxtaposed cooperating first and second substantially uncoated substrate alloy surfaces of an alloy based on at least one element selected from the group consisting of Fe, Co, and Ni, at least one of the cooperating alloy surfaces including greater than about 5 weight % total of elements selected from the group consisting of Al and Ti, the steps of:
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