[ materials ]
Similar reasoning must be applied in circumstances when hydrogen embrittlement potential in containment systems is evaluated based on data from materials testing in hydrogen gas . In this approach , it is imperative that properties of materials as well as environmental conditions in the testing relate to the hydrogen containment system in a conservative fashion . One specific example of the need to apply materials testing data in this judicious manner is represented by the 300-series stainless steels . For these steels , the potential for hydrogen embrittlement is highest at temperatures just below typical ambient conditions . Thus , in a containment system fabricated from 300-series stainless steel that operates at -50 ° C , the risk of hydrogen embrittlement cannot be reliably evaluated based on testing this steel in hydrogen gas at room temperature .
In summary , when assessing the potential for hydrogen embrittlement in containment systems , it is essential to consider the three variable types featured in Figure 1 . Although there are numerous specific variables that populate the spaces depicted in Figure 1 , the following list represents one variable from each space that deserves particular attention :
• Material strength . When procuring containment components that are not explicitly certified for gaseous hydrogen service , it is advisable to review the list of materials in the product drawing to identify any higher-strength alloys , such as 17-4 PH stainless steel , that raise concerns for hydrogen embrittlement .
• Time-variation of mechanical stresses . When containment components are subjected to cyclic mechanical stresses , the most effective means to account for hydrogen embrittlement is through quantitative analysis . These methods couple stress analysis of components with data from materials testing in hydrogen gas . Examples of such approaches are in the American Society of
Mechanical Engineers ( ASME ) codes for stationary pressure vessels ( ASME Boiler and Pressure Vessel Code , Section VIII , Division 3 , Article KD-10 ) and for pipelines ( ASME B31.12 ).
• Hydrogen gas pressure . For many metals , hydrogen embrittlement can be activated in gaseous hydrogen even at very low pressures ( for example , 1 bar or less ). For this reason , it cannot be assumed that there is a threshold pressure below which containment systems are safe from hydrogen embrittlement for all combinations of material properties and mechanical stress characteristics .
References
1
Journal of the Society of Materials Science ,
Japan 69.5 ( 2020 ): 395 – 400 .
2
MRS Bulletin 27 ( 2002 ): 680 – 682 .
About the CHS and HSP
Founded in 2018 , the Center for Hydrogen Safety ( CHS ) is a non-profit , unbiased , corporate membership organization promoting the safe operation , handling , and use of hydrogen and hydrogen systems across all installations and applications . CHS has more than 100 global member organizations and 14 strategic partners and utilizes best practices , lessons learned , education resources , conferences , webinars , workshops , and working groups to develop and share hydrogen safety knowledge . Visit www . aiche . org / chs .
A trusted and highly respected resource , the Hydrogen Safety Panel ( HSP ) is a pioneer in reducing knowledge barriers to hydrogen fuel cell deployment and enabling timely technology adoption by cities and communities . Building on its diverse knowledge , rich experience , and technical objectivity , this not-for-profit expert panel utilizes safety reviews , research , information dissemination , and training to help government agencies , industry and other stakeholders ensure that hydrogen is safely stored and handled . Visit https :// h2tools . org / hsp .
Hydrogen Tech World | Issue 9 | April 2023 25