Answer
316 Stainless Steel is often selected for wave springs in marine or chemical processing due to its molybdenum content, which provides resistance to pitting and crevice corrosion. However, 316 is a non-heat-treatable austenitic steel that gains its strength solely through cold working. This results in a lower yield strength compared to 17-7PH. In cyclic loading applications, the combination of a corrosive medium (like saltwater) and alternating stress leads to corrosion fatigue, where the fatigue limit of the material is significantly reduced. The chloride ions accelerate the initiation of surface cracks. Designers must keep the maximum operating stress below the reduced fatigue threshold and often apply a safety factor of $1.5$ to $2.0$ over the standard fatigue calculations to account for the environmental degradation of the surface integrity.
