Dimensional tolarance change

[Birdeye]

Material is AMS 5450 nickel. What would be the cause of material shrinkage up to .030 below the manufacture limit after initial usage? Material is utilized in aviation engine combustion case as a front flange assembly. Upon removal and measurement of flange outside diameter in ambient temperatures, shrinkage is noted. Subject material dimension allows for only .0005 wear for usable limit. History of shrinkage has been noted between .020 and .030 on this component. There is no interference fit between mating flanges and no other dimensional tolerance affected.

 

[Goahead]

A search with IHS Standard Store returned no documents for the said AMS. Is there an error in the number?
You do not specify the material thickness and if it is stamped or welded. Was the flange expanded in fabrication?
Shrinkage, as deformation in general, may be due to relaxation of stresses at operating temperatures.
If this is the case stress releaving was possibly not effective during manufacture.

http://www.welding-advisers.com/

 

[EdStainless]

AMS5540?
Are you sure that the part was annealed afer all of the forming?

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Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[kenvlach]

Is there shrinkage in all directions (volumetric shrinkage)?

Vacancy annihilation can cause shrinkage -- if original material was quenched or rapidly cooled, then reheat + slow cooling lets vacancies anneal out to the surface.
The maximum vacancy concentration for metals is 10^-4 to 10^-3 (of the metal lattice sites) just below the melting point. For methods to measure (differential dilatometry, electrical resistance, & spectroscopy) & calculate vacancy concentration, see Physical Metallurgy Handbook by A. K. Sinha (2003), sections 2.3-2.6.
The enthalpy of formation of a vacancy in nickel is 1.6-1.7 eV.

 

[israelkk]

I suspect the AMS is 5540 inconel 600 annealed