hydrogen embrittlement corrosion

Hydrogen embrittlement occurs when hydrogen dissolved in steel aggregates into hydrogen molecules, resulting in stress concentration that exceeds the steel’s strength limit and leads to the formation of tiny cracks within the steel, also known as white spots. Hydrogen embrittlement can only be prevented, not cured. Once hydrogen embrittlement occurs, it cannot be eliminated. Trace amounts of hydrogen (on the order of 10–6) that enter the steel during its smelting process and during the manufacturing and assembly of parts (such as electroplating and welding) can cause the material to become brittle or even crack under the effect of internal residual stresses or external stresses. The properties of the steel can be restored through dehydrogenation treatment (for example, by heating to above 200°C for several hours to reduce internal hydrogen) before cracking occurs. Therefore, internal hydrogen embrittlement is reversible. Please refer to: http://bbs.hcbbs.com/thread-321598-1-1.html