Official Answer
Answer
A286 is an iron-base superalloy that provides high strength and oxidation resistance at temperatures up to $1000^{\circ}F$ ($538^{\circ}C$). It is particularly valuable in the hot sections of gas turbines where standard stainless steels would lose their temper and relax. A286 is hardened by the precipitation of the $\gamma'$ phase during a long aging cycle (e.g., $1325^{\circ}F$ for 16 hours). For spiral rings, A286 offers a stable coefficient of thermal expansion $\alpha$ that closely matches the turbine housing materials, minimizing the change in 'cling' or clearance as the engine transitions from cold-start to full-power temperatures.
