FATIGUE CRACK GROWTH RATES OF API X70 PIPELINE STEELS IN PRESSURIZED HYDROGEN GAS COMPARED WITH AN X52 PIPELINE IN HYDROGEN SERVICE
Elizabeth S. Drexler, Andrew J. Slifka, Robert L. Amaro, Damian S. Lauria, Jeffrey W. Sowards
At the present time, steel selection for hydrogen pipelines is limited to API X52 grade. However, the code is being modified to include higher strength steels, such as X70. Fatigue crack growth (FCG) tests were conducted at NIST (Boulder) on an X52 pipeline steel that is currently in service transporting hydrogen gas, as well as two X70 pipeline steels. The compact tension specimens were tested in hydrogen gas pressurized to 5.5 MPa or 34 MPa. A comparison of these tests, all conducted at a cyclic loading frequency of 1 Hz, shows that there is very little difference between the FCG rates of the base metal among the three steels at a given hydrogen pressure. All three base metals exhibited some increase in FCG rate at a hydrogen pressure of 34 MPa compared with 5.5 MPa. Analysis of the data provide rationale for allowing higher strength steels to be used for hydrogen gas transport and distribution, as well as possible limitations on which microstructural constituents are compatible for hydrogen pipelines.
, Slifka, A.
, Amaro, R.
, Lauria, D.
and Sowards, J.
FATIGUE CRACK GROWTH RATES OF API X70 PIPELINE STEELS IN PRESSURIZED HYDROGEN GAS COMPARED WITH AN X52 PIPELINE IN HYDROGEN SERVICE, International Hydrogen Conference 2016, Moran, WY, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921512
(Accessed February 28, 2024)