Official Answer
Answer
A286 (ASTM A638) is an austenitic precipitation-hardenable steel that maintains excellent ductility and impact strength at cryogenic temperatures, unlike ferritic or martensitic steels which become brittle. For cryogenic wave springs, the material is typically solution treated and age hardened to optimize the gamma-prime precipitates. The thermal expansion coefficient $\alpha$ must be accounted for in the assembly design, as the spring will contract more than the surrounding carbon steel housing at liquid nitrogen temperatures. The Modulus $E$ also increases slightly as temperature drops, leading to a higher spring rate in service.
