Session: MF-02-02 Materials for Hydrogen Service-Effect of Gas Impurities

Paper Number: 122291

122291 - Effect of Oxygen Impurities on Subcritical Crack Growth in High-Pressure Hydrogen Environments 

In this work, the effects of oxygen impurities on gaseous hydrogen environment-assisted cracking are studied for several pipeline and commercial steels.  Exposure to gaseous hydrogen is known to negatively affect the fracture resistance, fatigue life, and ductility of many commonly used materials, including pipeline steels, and can induce subcritical crack growth.  Numerous studies have shown that relatively low amounts of oxygen impurities (e.g., 100PPM) can significantly mitigate these effects of hydrogen on fatigue and fracture in laboratory tests.  However, long-term laboratory tests (100s of hours) have not been reported confirming the observations on relatively short time frames (a few hours). Therefore, this study seeks to better characterize the mitigating effects of oxygen impurities on hydrogen embrittlement over longer timescales that are more representative of hydrogen transportation and storage applications.  To this end, constant displacement fracture tests were carried out in high pressure (>1000 bar) pure hydrogen and at similar pressure with a mixed gas (100PPM and 1000PPM oxygen + hydrogen).  The three steels utilized in this study were: X100 pipeline steel, ASME SA-372 Grade L, and ASME SA-372 Grade J with yield stresses ranging between 700 and 800MPa.  The applied load on the fracture samples was continuously monitored throughout testing to determine the time to crack propagation (incubation time), crack growth rates, and crack arrest thresholds.  While the addition of 100PPM and 1000PPM oxygen to high pressure hydrogen environments was found to delay the onset of subcritical crack propagation, it did not prevent crack growth in any of the conditions, nor did the oxygen affect the crack growth rates or crack arrest thresholds.  Based on the results presented in this work, it appears that oxygen should not be relied upon for long-term mitigation of gaseous hydrogen embrittlement.

 

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525.

Presenting Author: Robert Wheeler Sandia National Laboratories

Presenting Author Biography: Rob Wheeler is a postdoctoral research associate at Sandia National Laboratories in the Hydrogen Effects on Materials Lab.

Authors:

Robert Wheeler Sandia National Laboratories
Joseph Ronevich Sandia National Laboratories
Chris San Marchi Sandia National Laboratories