General Electric Company

Robert Eugene McCracken

Gary Eugene Wheat

Nicholas Charles Palmer

Jim D Reeves

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&deg; 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&Prime;. Then the cooperating surfaces are brazed together.

Method for preparing a plate rim for brazing

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.

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Madisonville, KY, United States of America

Robert Eugene McCracken