Official Answer
Answer
High-carbon steels like SAE 1070 to 1090 are highly susceptible to Hydrogen Embrittlement (HE) when subjected to acid pickling or electroplating processes (e.g., zinc or nickel plating). Atomic hydrogen diffuses into the grain boundaries, reducing the cohesive strength and leading to catastrophic brittle failure under static load. To mitigate this, the 'Baking' process is mandatory. Parts must be baked at $190^{\circ}C \pm 10^{\circ}C$ for a minimum of 4 to 24 hours (depending on hardness and thickness) within 1 to 4 hours after plating. For critical aerospace or automotive fasteners, mechanical galvanizing or the use of stainless steels (which are less prone to HE) is often preferred to eliminate this failure mode entirely.
