Corrosion fatigue and fatigue crack growth in air tests were comparatively conducted on an X52 pipelines steel. Fatigue crack growth rates in air were lower than corrosion fatigue crack growth rates due to the absence of hydrogen and mechanical dormancy arisen from low temperature creep at low cyclic frequencies. Mechanical dormancy can commonly occur during operation of both oil and gas pipelines. Crack growth in near neutral pH environments can be well rationalized by a combined loading factor, (ΔK)2Kmax/fα, which reflects the synergistic interaction between the mechanical driving force and the hydrogen effects. Hydrogen plays a decisive role in terms of crack growth in pipelines steels exposed to near neutral pH environments.

This content is only available via PDF.
You do not currently have access to this content.