Specialist resistance to hydrofluoric acid and flowing seawater — see the grade table below for full datasheets and equivalents within this family.
See All Grades ↓Monel is a nickel-copper alloy family developed specifically for two demanding services that even duplex and standard stainless struggle with: hydrofluoric acid alkylation and flowing seawater. It's a specialist choice rather than a general-purpose upgrade, reserved for applications where its specific corrosion mechanism advantage genuinely matters.
Monel 400 is the standard annealed grade covering most applications; Monel K500 adds age-hardening for roughly three times the yield strength where higher mechanical strength is also required alongside Monel's corrosion resistance.
| Grade | Designation | Best For |
|---|---|---|
| Monel 400 | UNS N04400 | HF alkylation, flowing seawater, general Monel applications |
| Monel K500 | UNS N05500 | Where higher strength is needed alongside Monel's corrosion resistance |
K500 is a precipitation-hardenable variant with added aluminum and titanium, giving roughly triple the yield strength of standard 400 through age-hardening heat treatment.
Nickel forms a protective fluoride film in HF service that resists further attack — a mechanism stainless steel's chromium oxide layer doesn't replicate in this specific environment.
Not really — it's a specialist choice for HF acid and seawater specifically. For general chloride resistance, duplex steel is usually more cost-effective; for broad acid resistance, Hastelloy is the better fit.
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 composition and temperature — our engineering team will confirm the right grade.
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