Answer
302 Stainless Steel is a work-hardening alloy. During the edge-winding of a spiral ring, the material is significantly cold-worked, which increases its tensile strength and fatigue limit. However, the 'Fatigue Limit' (the stress at which the material can withstand infinite cycles) for 302SS is typically around $25-30$ percent of its ultimate tensile strength ($UTS$). In high-vibration environments, if the cyclic stress $\sigma_{alt}$ caused by the vibration exceeds this limit, the ring will fail via crack propagation. Designers must calculate the 'Preload Stress' and ensure the 'Vibratory Stress' superimposed on it stays within the 'Safe' zone of a modified Goodman diagram. For extreme vibration, switching to a material with a higher fatigue-to-UTS ratio, like 17-7PH, is often necessary.
