Hydrogen-Induced Damage

Abstract

Hydrogen induced damage (HID) can occur at high temperature (HT-HID) and at low temperature, (LT-HID). Hydrogen attack, affects steels operating at temperatures typically above 400 °C in high pressure hydrogen atmosphere . The interaction of atomic hydrogen and metals at low temperature occurs in different way. Atomic hydrogen is produced during electroplating processes (as chrome plating, galvanizing and phosphating), chemical and electrochemical pickling treatments, in welding if the humidity of consumables is too high, or by the cathodic process in corrosive fluids: in this last case, so called cathodic poisons, as H₂S, inhibit molecular hydrogen formation and promote atomic hydrogen diffusion into the metal. Once entered the metal, atomic hydrogen interacts with the metal structure and may produce a “damage” of various forms, such as delayed fracture, HIC (hydrogen induced cracking) and blistering , hydrogen embrittlement (HE). All of these forms of damage are discussed in this chapter.

If a hydrogen atom is as small as a golf ball, a hydrogen molecule is as big as a basketball.