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Method for preparing a plate rim for brazing

Imported: 24 Feb '17 | Published: 09 Apr '02

Jim Dean Reeves, Gary Eugene Wheat, Nicholas Charles Palmer, Robert Eugene McCracken

USPTO - Utility Patents

Abstract

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.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a diagrammatic, fragmentary, partially sectional view of an open radially outer end of a hollow air-cooled turbine blade with an end plate rim as a tip cap brazed to an inner surface of the blade wall.

FIG. 2 is an enlarged fragmentary sectional view of a portion of FIG. 1 about the brazed joint.

Claims

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:

2. The method of claim 1 in which the depth is no greater than about 0.0015″.

3. The method of claim 2 in which:

4. The method of claim 3 in which:

5. The method of claim 3 in which: