Mechanism of Hydrogen Induced Cracking of Carbon Steel in Simulated Atmospheric Environment Containing SO₂

Mechanism of hydrogen induced cracking of carbon steel was investigated by Devnathan-Stachurski double electrolytic cell and slow strain rate test (SSRT) in simulated atmospheric environment containing SO2. The fracture strain decreased with increasing the concentration of SO2 at the same strain rate 6.67×10-7S-1. The SEM fractographs of the specimens also showed that the susceptibility to stress corrosion cracking (SCC) increased with increasing the concentration of SO2. The hydrogen permeation test showed that hydrogen permeation current increased with increasing the concentration of SO2. H2SO3 hydrolyzed to H+ was the reason of the appearance of the first peak value of current. Regeneration of acid induced the second peak value of current.