High-temperature hydroprocessing units put hydrogen attack resistance at the center of material selection, verified directly against API 941 Nelson curves for the specific temperature and hydrogen partial pressure.
| Dominant Failure Mode | High-temperature hydrogen attack |
| Governing Standard | API 941 Nelson curve compliance |
| Typical Material Default | Alloy Steel (Cr-Mo), Inconel for the most severe hydroprocessing units |
| Typical Structural Type | U-Tube for the highest-pressure, highest-temperature units |
Refinery hydroprocessing units require material selection checked directly against Nelson curve limits.
They chart the maximum operating temperature a given steel chemistry can tolerate at a specific hydrogen partial pressure before hydrogen attack becomes a risk — refinery material selection for hydroprocessing units is checked directly against these curves.
No — the most severe combinations of temperature and hydrogen partial pressure exceed what standard Cr-Mo alloy steels can tolerate, requiring a move to Inconel or similar for those specific units.
Our engineering team reviews the specific temperature and hydrogen partial pressure conditions provided against the applicable Nelson curve before confirming material selection.
Every enquiry is checked against governing code, material compatibility and manufacturing feasibility before a quote is issued. Use our product, material, grade and standards guides to freeze the RFQ — then confirm with engineering.
Send your fluid service, pressure class and governing standard — we'll confirm the right product and material.