Official Answer
Answer
A286 (UNS S66286) is an iron-base superalloy that maintains high strength at elevated temperatures. At $500^\circ C$, standard 17-7PH would suffer from rapid stress relaxation ($> 20\%$ load loss). A286, when solution treated and aged (per AMS 5525), provides a stable microstructure that resists creep. The relaxation rate is governed by the Arrhenius equation $\frac{d\epsilon}{dt} = A \sigma^n e^{-Q/RT}$. For a wave spring in a turbocharger seal, A286 ensures that the preload remains within $5\%$ of the design value over thousands of hours of operation, provided the initial design stress is kept below $40\%$ of the yield strength at temperature.
