Monel 400 Hex Nuts
MT.BOLTS manufactures Monel 400 Hex Nuts, using high-corrosion-resistant Monel 400 (UNS N04400) alloy, a solid solution nickel-copper alloy known for its outstanding resistance to seawater, acids, and alkaline media. These hex nuts are ideal for critical bolted joints in marine engineering, chemical processing equipment, and high-temperature environments.
Monel 400 Hex Nuts—Specifications:
- Diameter: M3 to M64 | #4 to 2.5″
- Thread Pitch: Metric (Coarse/Fine) | UNC/UNF
- Standards:
- ASME B18.2.2 (Hex Nuts—Inch)
- DIN 934 / ISO 4032 (Hex Nuts—Metric)
- Material Specifications:
- ASTM F467 (Nonferrous Nuts)
- ASTM B164 (Monel 400 Rod/Bar)
- Finish: Plain (natural), optional PTFE or MoS₂ coating
- Thread Type: Standard, fine, or customized on request
- Marking: Grade and batch marking available upon request
Monel 400 Hex Nuts Features & Benefits:
- Exceptional corrosion resistance in seawater, brine, acids, and alkaline environments
- Non-magnetic and maintains stability at elevated temperatures up to 550°C
- Excellent mechanical strength and ductility for demanding fastening requirements
- Resistant to galling and suitable for high-pressure, anti-corrosion bolted assemblies
- Ideally matched with Monel 400 bolts and washers to ensure full system compatibility and long-term performance
Monel 400 Hex Nuts Chemical Composition (ASTM B164)
| lement | Nickel (Ni) | Copper (Cu) | Iron (Fe) | Manganese (Mn) | Silicon (Si) | Carbon (C) | Sulfur (S) |
| Content (%) | ≥ 63.0 | 28.0–34.0 | ≤ 2.5 | ≤ 2.0 | ≤ 0.5 | ≤ 0.3 | ≤ 0.024 |
Monel 400 Hex Nuts Mechanical Properties (Typical per ASTM F467)
| Property | Tensile Strength | Yield Strength | Elongation | Hardness |
| Value | ≥ 70 ksi (483 MPa) | ≥ 25 ksi (172 MPa) | ≥ 30% | 110 – 230 HB (Brinell) |
Matching Standards for Monel 400 Hex Bolts and Nuts
| Bolt Standard | Matching Nut Standard | Material Description |
| ASTM F468 (Monel 400 bolts) | ASTM F467 (Monel 400 nuts) | Designed for paired use to ensure consistent corrosion resistance and mechanical strength |
| DIN 933 / ISO 4017 | DIN 934 / ISO 4032 | Metric/European standards – thread and material must match |
Note: Monel 400 has a different thermal expansion coefficient compared to stainless steel. It is not recommended to mix Monel bolts with stainless steel nuts.
Selection Guide for Monel 400 Hex Nuts
Choosing the correct Monel 400 hex nuts depends on service conditions such as corrosion level, temperature, mechanical stress, and compatibility with mating components.
| Environment | Selection Recommendation |
| Marine/Offshore | Use with Monel 400 bolts and washers (ASTM F468/F467) for full corrosion resistance in seawater and salt spray |
| Chemical Processing | Ensure compatibility with aggressive media (e.g., acids, alkalis); consider PTFE-coated washers to prevent galvanic corrosion |
| High Temperature (≤550°C) | Suitable for long-term use; avoid applications >600°C to prevent loss of mechanical strength |
| Underground/Subsea | Recommend sealed assemblies with anti-galling washers or sealants to prevent moisture ingress |
Why Choose MT.BOLTS
- Material Diversity
- Standardized Production
- Ample Inventory
- Competitive Pricing
- Low-MOQ Customization
Monel 400 Hex Nuts Features & Benefits:
- Excellent Corrosion Resistance
Resistant to seawater, salt spray, acids, and alkaline environments—ideal for harsh chemical and marine applications. - Non-Magnetic and High Thermal Stability
Maintains structural stability and performance at elevated temperatures up to 550°C; suitable for sensitive and high-heat applications. - Solid Mechanical Strength and Ductility
Offers moderate tensile strength with superior elongation and toughness; resists deformation and galling under load. - Anti-Galling and Thread Integrity
Suitable for repeated assembly and disassembly without thread seizure; can be enhanced with optional lubricious coatings (PTFE, MoS₂). - Material Compatibility
Designed to work with Monel 400 bolts and washers, ensuring consistent thermal expansion and electrochemical behavior.
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Application of Monel 400 Hex Nuts
Monel 400 Hex Nuts are commonly used in:
- Marine & Offshore Structures
Fastening components exposed to seawater, wave splash, and salt spray. - Chemical Processing Equipment
In contact with acids, alkalis, solvents, or aggressive chemical vapors. - High-Temperature Assemblies
Heat exchangers, condensers, and refinery equipment operating up to 550°C. - Power Generation & Nuclear Plants
Environments requiring high corrosion resistance and non-magnetic properties. - Oil & Gas Fields
Suitable for sour gas service and subsea bolting where corrosion fatigue resistance is critical.
FAQ About Monel 400 Hex Nuts
Monel 400 is a nickel-copper alloy (UNS N04400) with excellent resistance to corrosion, especially in marine and acidic environments. It is used in fasteners, piping systems, valves, and more.
Monel 400 Hex Nuts are typically manufactured to ASTM F467 for nonferrous nuts, with dimensional standards per ASME B18.2.2 (inch series) or DIN 934 / ISO 4032 (metric series).
It’s not recommended due to the potential for galvanic corrosion and differing thermal expansion rates. Monel 400 nuts should be paired with Monel 400 bolts (ASTM F468) for optimal performance.
MT.BOLTS supplies full material certification including EN 10204 3.1, chemical and mechanical test reports, and traceability documentation.
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