Temperature Range (1.4)
Criticality: High
Progress: Addressed, Not Adequately
Score: 20
DOT Relevance: §192.51 – §192.65
Description of Key Area
While it is generally true that higher pressures increase the susceptibility
of metals to hydrogen-assisted fracture, temperature effects are not as
systematic. For example, some metals such as austenitic stainless steels
exhibit a local maximum in hydrogen-assisted fracture susceptibility as a
function of temperature.
Subpart B (Materials) of 49 CFR 192 “prescribes the minimum
requirements for the selection and qualification of pipe and components for use
in pipelines.” The code further states that, “Materials for pipe and components
must be able to maintain the structural integrity of the pipeline under
temperature and other environmental conditions that may be anticipated.”
Discussion of Criticality
Anticipated temperature operating ranges for hydrogen
distribution piping may range between ‑40 and 150°C (-40 and 302°F).
The temperature range should be consistent with 49 CFR 192.
Discussion of Progress
ASME B31.12 will include information equivalent to ASME B31.3, ASME
B31.8 and NFPA 54 for natural gas.
Work is underway at SNL examining hydrogen-assisted fracture
which includes an assessment of temperature effects.
Recommendations
Research is needed to compile data regarding temperature
transition ranges from hydrogen embrittlement to hydrogen attack (lower
temperature data on embrittlement exists and most of the lower temperature
alloys like 316 stainless are not really affected by embrittlement).
Engineering data is needed in order for proper design decisions to be made.
Conclusions from research should be incorporated where necessary into the
federal code.
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