Answer
Carbon steel spiral rings (SAE 1070-1090) are highly susceptible to hydrogen embrittlement during acid pickling or zinc/cadmium electroplating. Atomic hydrogen is absorbed into the high-strength martensitic lattice, migrating to areas of high stress (the inner diameter of the ring). This leads to brittle fracture under loads well below the design limit. To mitigate this, a 'baking' process is mandatory: rings must be baked at $375-400^{\circ}F$ ($190-205^{\circ}C$) for at least $4$ to $24$ hours within one hour of the plating process. This allows the hydrogen to effuse out of the metal. Failure to bake results in 'delayed fracture', where the ring may appear healthy after installation but snaps suddenly hours or days later under static load.
