Criticality: High Progress: Addressed, Not Adequately Score: 20 DOT Relevance:
Description of Key Area
Some metallic components, including cylinders, cylinder liners,
valve components, and tubing may incorporate welded construction.
Discussion of Criticality
Welding of metals can introduce stress concentrations, and reduce
strength and elongation of welded materials. Welding of some austenitic
stainless steels that are resistant to hydrogen embrittlement can produce
martensitic structures that are subject to hydrogen embrittlement.
Discussion of Progress
Welded metallic components are currently being used in hydrogen
storage. However, the use of welded components becomes more of an issue as
hydrogen gas pressure increases.
Recommendations
Industry and DOT should be developing performance based
requirements in standards and regulations that demonstrate capability of any
welds in components for hydrogen storage are of sufficiently strong and
resistant to hydrogen embrittlement. It may be required to limit the use of
welds in hydrogen storage components, to specify that only certain metals can
be welded, or that higher safety factors will be required for welded
components.
