Answer
The primary failure mechanism is Hydrogen Embrittlement (HE). During the zinc electroplating process, atomic hydrogen is evolved at the cathode and diffuses into the high-strength carbon steel lattice (e.g., SAE 1070/1090). Because wave springs are high-stress components, the presence of hydrogen at grain boundaries leads to sub-critical crack growth and sudden, brittle fracture under static loads significantly below the yield strength. To mitigate this, a mandatory de-embrittlement baking process (typically $375^{\circ}F \pm 25^{\circ}F$ for at least 3-8 hours) must be performed within 4 hours of plating. Failure to do so results in 'delayed fracture,' where the spring appears intact after installation but fails catastrophically within hours or days of operation.
