The hydrogen-induced cracking of X70 pipeline steel was investigated in low-temperature and low-dissolved-oxygen seawater by means of potentiodynamic polarization, slow strain rate tests (SSRT), and hydrogen permeation measurements. The results showed that the hydrogen evolution potential of X70 steel in low-temperature and low-dissolved-oxygen seawater decreased compared with the normal-temperature seawater. The susceptibility to hydrogen embrittlement increased as the potential shifted in the negative direction. When the polarization potentials were below −1,050 mV vs. saturated calomel electrode (SCE) in low-temperature and low-dissolved-oxygen seawater, the fracture surfaces exhibited quasi-cleavage fracture.

Subject
Scanning electron microscopy, Hydrogen induced cracking, Hydrogen embrittlement, Hydrogen permeation, Cathodic potential, Hydrogen evolution, Diffusion, Seawater, Steel, Risk reduction, Fractography, Electrode potential, Hydrogen
Keywords:
cathodic polarization, corrosion, hydrogen-induced cracking, low dissolved oxygen, low temperature, X70 pipeline steel
© 2012 NACE International
2012
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