Environmental Engineering Reference
In-Depth Information
Figure 8.14
Nelson curves showing the operating limits of carbon and alloy steels in
contact with hydrogen at high temperature and pressure.
gen. The disintegration of oxygen-containing copper in the presence of hydrogen
is a typical example of hydrogen attack.
8.4 THEORIES OF HYDROGEN DAMAGE
Several theories have been proposed for the mechanism of various types of hydro-
gen damage encountered. The prominent among these are as follows:
1.
Hydrogen pressure theory
2.
Surface adsorption theory
3.
Decohesion theory
4.
Enhanced plastic flow theory
5.
Decarburization, and
6.
Hydride formation
Hydride formation is an established mechanism for embrittlement of titanium,
zirconium, and several other metals and has been discussed in the section ''Em-
brittlement Due to Hydride Formation.'' However, the embrittlement of steels,
nickel alloys, and aluminum alloys is not due to hydride formation. Decarburiza-
tion is the cause of hydrogen attack of steels at high temperatures, which has been
