Type of hydrogen damage
Decarburization - It is often produced by moist hydrogen at high temperatures, and it lowers the tensile strength of steel.
Hydrogen attack
Hydrogen Blistering - The interior surface is in contact with the electrolyte and the exterior is exposed to the atmosphere. Hydrogen evolution occurs on the inner surface as a result of corrosion reaction. some of the hydrogen atoms diffuse into the metal rather than combining into molecules. Hydrogen molecules are formed on the exterior surface. if there is a void, hydrogen atoms are combined in the void to form molecules, which can not diffuse. The concentration and pressure of hydrogen gas increases, which causes damage to the metal.
Hydrogen embrittlement - The same initial cause penetration of hydrogen atoms into the metal structure.
- Alloys are most susceptible to cracking in their highest strength level.
- The tendency for embrittlement is increased with increasing hydrogen concentration in the metal.
- Other terms are used to describe hydrogen embrittlement
Hydrogen stress cracking: if the absorption is due to contact with hydrogen gas.
SCC: if the absorption is due to the corrosion reaction.
Sulfide stress cracking: if corrosion is due to the presence of hydrogen sulfide.
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