US 5,672,261 AGranted

Method for brazing an end plate within an open body end, and brazed article

AssigneeGeneral Electric Company

InventorsGary E. Wheat, Robert E. McCracken, Nicholas C. Palmer

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Abstract

A method for preparing a Ni base superalloy inner wall surface of a body open end, such as an end of a turbomachinery blade, and an end plate, such as a blade tip cap, for brazing together at a rim of the end plate includes electrochemically removing oxides from the inner wall surface. The end plate is prepared, at least at its rim, by first removing surface and subsurface oxides, for example by mechanical abrading or a combination of such abrading and acid cleaning. Then at least the rim is electroplated with Ni which is heated to diffuse the Ni into the rim substrate. This provides an improved combination of surfaces for brazing for example with a Ni base brazing alloy. After brazing the rim to the inner wall, there is provided an article with an improved relatively low oxide brazed joint, including less than about 20 volume % oxides, and a plate rim of substantially Ni along with elements diffused from the brazing alloy and the rim.

Claims8

Dependent claims

In a method for making an article which includes a body having a hollow interior and an open end comprising a wall of a Ni base superalloy which includes at least about 5 weight % total of at least one element selected from the group consisting of Al and Ti, the wall having an inner wall surface which defines at least a portion of the open end, and an end plate bridging at least a portion of the open end, the end plate including a plate rim shaped to match with at least a portion of the inner wall surface and brazed with the inner wall surface at a brazing temperature, the steps of:

electrochemically removing material from the inner wall surface, with the inner wall surface connected as an anode, to remove oxides from the inner wall surface;
preparing the plate rim for brazing to the inner wall surface by:
a) removing surface and subsurface oxides at least from the rim;
b) electroplating Ni at least on the rim;
c) heating the electroplated Ni to diffuse the Ni at least into the rim;
and,
brazing the end plate to the inner wall surface at the rim at the brazing temperature.

4 more elements

Dependencies are inferred from the claim text.