Note that molecular gaseous hydrogen does not have the same effect as atoms or ions released into solid solution in the metal.
Hydrogen picked up during melting and casting segregates at internal voids and discontinuities and produces these defects during forging.
Steel containment vessels exposed to extremely high hydrogen pressures develop small fissures or micro perforations through which fluids may leak.
Many steps can be taken to reduce the entry of hydrogen into metals during critical operations like melting; casting; working (rolling, forging, etc.
There are various methods of adequately identifying and monitoring hydrogen damage, including ultrasonic echo attenuation method, amplitude-based backscatter, velocity ratio, creeping waves/time-of-flight measurement, pitch-catch mode shear wave velocity, advanced ultrasonic backscatter techniques (AUBT), time of flight diffraction (TOFD), thickness mapping and in-situ metallography – replicas.