Monel 400 — UNS N04400
Monel
Monel is a nickel-copper alloy prized for exceptional resistance to seawater, hydrofluoric acid, and caustic alkalis. We supply Monel 400 in sheet and shim gauges for gasket fabrication, spiral wound gasket components, and corrosion-resistant shims in marine, chemical processing, and oil and gas applications.
At a Glance
Temperature Range
-200 °C to +538 °C continuous
Thickness Range
0.05 mm to 6 mm (shim and sheet)
Available Forms
Technical Properties
Typical values across stocked grades. Specific grade data sheets available on request.
Alloy Composition
Nickel (Ni)
63.0–70.0%
Copper (Cu)
28.0–34.0%
Iron (Fe)
≤2.5%
Manganese (Mn)
≤2.0%
Carbon (C)
≤0.30%
Silicon (Si)
≤0.50%
Physical Characteristics
Density
8.80 g/cm³
Tensile Strength
480 MPa min per ASTM B127 (annealed); typical 480–620 MPa
Elongation at Break
35–50% in 50 mm (ASTM E8)
Thermal Conductivity
21.8 W/m·K at 100 °C
Chemical Resistance
Resistant To
- Seawater and brackish water (excellent; the standard marine alloy for corrosive service)
- Hydrofluoric acid in the liquid phase at ambient to moderate temperature. One of the few metals resistant to HF; see limitations for hot aerated HF vapour.
- Caustic soda and other alkalis at high concentration and temperature
- Deaerated sulphuric acid (dilute to moderate)
- Fluorine and hydrogen fluoride gas
- Neutral and alkaline salt solutions
Limited Resistance
- Oxidising acids such as nitric acid and ferric chloride; Monel is vulnerable to oxidising media
- Aerated sulphuric acid at elevated temperature
- High-velocity seawater (erosion-corrosion risk)
Not Recommended
- Nitric acid at any concentration. Use stainless steel or Hastelloy instead
- Ferric chloride or cupric chloride solutions, which cause pitting
- Strongly oxidising environments (Monel relies on reducing conditions for corrosion protection)
- Sulphur-bearing gases above ~315 °C (600 °F per Special Metals SMC-053), where embrittlement is a risk
Standards & Certifications
Standards Compliance
Common Applications
- Marine and offshore flange gaskets (seawater service)
- Hydrofluoric acid alkylation unit gaskets
- Caustic evaporator and concentrator seals
- Oil and gas production (sour service gaskets)
- Spiral wound gasket winding and inner rings
- Chemical processing vessel gaskets (reducing acids)
- Submarine and naval equipment seals
- Salt production and brine processing
Not Recommended For
- Vulnerable to oxidising acids such as nitric acid and ferric chloride. Performs in reducing environments only; use Hastelloy for oxidising media.
- Subject to stress corrosion cracking in hot, aerated hydrofluoric acid vapour. Verify conditions before specifying.
- Higher cost than 316 stainless steel, only justified where the specific corrosion resistance is needed
- Work-hardens during machining, so sharp tooling and appropriate speeds are required
- Sulphur attack above ~315 °C (600 °F per Special Metals SMC-053): avoid contact with sulphur-bearing gases at elevated temperature
Available Grades
Monel 400 Sheet
Standard nickel-copper alloy sheet for gasket fabrication and corrosion-resistant shims. Our standard alloy for seawater and hydrofluoric acid service.
Monel 400 Shim (0.05–0.5 mm)
Precision-rolled thin-gauge Monel 400 for shimming and spacing in marine and chemical environments.
Need Monel?
We supply monel in sheet, roll, and custom die-cut forms. Contact our team for pricing, data sheets, or technical assistance.
Disclaimer
This resource is provided for general engineering reference only and does not constitute professional advice, specification, or guarantee of performance. Actual results depend on specific application conditions. Universal Gaskets Pty Ltd accepts no responsibility or liability for decisions made based on this information. For full terms, see our Terms & Conditions.