Official Answer
Answer
The primary sign of hydrogen induced delayed fracture is a 'clean' brittle fracture that occurs hours or days after the spring has been installed and placed under load, despite no immediate failure during assembly. The fracture surface usually shows intergranular cracking under a Scanning Electron Microscope (SEM). This is caused by hydrogen atoms migrating to areas of high tensile stress (the wave peaks). To prevent this, the spring must be baked at $190^{\circ}C \pm 10^{\circ}C$ within 1-4 hours of plating to drive out the diffused hydrogen. Failure to bake promptly allows the hydrogen to trap at grain boundaries, leading to embrittlement.
