Official Answer
Answer
High-carbon steel like SAE 1070 is highly susceptible to hydrogen embrittlement (HE) during acid pickling and electroplating processes (e.g., zinc or nickel plating). Atomic hydrogen diffuses into the grain boundaries, particularly in the high-stress areas at the wave peaks, leading to brittle fracture under load. To mitigate this, a 'bake-out' process is mandatory. The springs must be placed in an oven at $190^∘C$ to $220^∘C$ within 1 to 4 hours of plating. The baking duration (typically 8 to 24 hours) allows the hydrogen to diffuse out of the steel matrix. For critical aerospace components, mechanical plating or organic coatings are often substituted to eliminate the risk of HE entirely.
