Hydrogen damage

Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen.

Hydrogen is present practically everywhere, several kilometres above the earth and inside the earth. Engineering materials are exposed to hydrogen and they may interact with it resulting in various kinds of structural damage. Damaging effects of hydrogen in metallic materials have been known since 1875 when W. H. Johnson reported “some remarkable changes produced in iron by the action of hydrogen and acids”. During the intervening years many similar effects have been observed in different structural materials, such as steel, aluminium, titanium, and zirconium. Because of the technological importance of hydrogen damage, many people explored the nature, causes and control measures of hydrogen related degradation of metals. Hardening, embrittlement and internal damage are the main hydrogen damage processes in metals. Hydrogen may be picked up by metals during melting, casting, shaping and fabrication. They are also exposed to hydrogen during their service life. Materials susceptible to hydrogen damage have ample opportunities to be degraded during all these stages.