Decarbonization›H₂ Embrittlement Screening
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H₂ Embrittlement Screening

Hydrogen · Composite-risk score · NACE MR0175 / ASME B31.12

H₂ Embrittlement Risk Screening
Composite-score classification of hydrogen-embrittlement risk based on steel grade, operating pressure, hardness, and temperature. Generates targeted recommendations for material selection and verification testing per NACE MR0175 / ISO 15156 / ASME B31.12 Mandatory Appendix IX.
⚠ Heuristic screening tool — preliminary use only. The 0–100 composite score is a rubric, not a code-prescribed result. ASME B31.12 Mandatory Appendix IX is the controlling document. The 22 HRC threshold is borrowed from NACE MR0175 sour-service by analogy. Base-metal hardness is a proxy for the actual primary HE failure location — the weld heat-affected zone (HAZ). Project-specific welding-procedure qualification with HAZ hardness mapping is required before final design. Verify all results with a licensed PE.

Material

HRC

Service

bara
°C

📚 Learn the Theory

Hydrogen embrittlement of steel: HEDE/HELP/AIDE mechanisms, NACE MR0175 hardness limits, ASME B31.12 Mandatory Appendix IX qualification, and risk screening.

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Engineering Basis

  • Composite score (0–100) from grade (0–25) + pressure (0–25) + hardness (0–30) + temperature (0–20).
  • NACE/AMPP MR0175 / ISO 15156 hardness limit: 22 HRC (sour service applied analogously to H₂).
  • HE most severe near room T; vanishes outside ±100 °C of 25 °C.
  • Higher grade + higher pressure → more atomic H diffusion into steel matrix.
  • Standards: NACE/AMPP MR0175, ISO 15156, ASME B31.12 Mandatory App IX, ASTM E1681.
  • Screening only — final qualification requires K_IH testing in H₂ per ASTM E1681 / SSPC.

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