Monel 401 Fasteners – UNS N04401 Screws, Nuts & Threaded Inserts
ASC LLP, Mumbai, supplies Monel 401 fasteners in UNS N04401 to drawing: screws, nuts, washers, studs, threaded inserts and speed nuts / spring clips, made from Monel 401 wire, rod and strip. They come with EN 10204 3.1 certificates. Monel 401 is part of our Monel range.
What is Monel 401?
Monel 401 is a nickel–copper alloy with 40–45% nickel and the balance copper. It has less nickel and more copper than Monel 400. This gives it a stable, fairly high electrical resistivity and makes it practically non-magnetic. It was developed for electrical and electronic use: wire-wound resistors, precision resistance foils, contacts and terminals. It also keeps the good general corrosion resistance of the Ni-Cu family. Monel 401 cannot be hardened by heat treatment; it is strengthened only by cold work.
Monel 401 Fasteners – Quick Facts
- Grade: Monel 401, UNS N04401 (Ni 40–45%, Cu balance)
- Forms supplied: machine screws, nuts, washers, studs, threaded inserts, speed nuts and clips, terminals
- Raw material: N04401 wire, rod and strip
- Standard: no ASTM fastener specification covers N04401 – supplied to drawing, with dimensions to ISO / DIN / ASME B18 where applicable
- Certificate: EN 10204 3.1 with chemistry and test results
Types of Monel 401 Fasteners We Supply
- Machine screws & set screws – small-diameter screws for electrical and instrument assemblies.
- Hex nuts, lock nuts & washers – flat and spring washers punched from 401 strip.
- Studs & threaded rod – short studs and terminal posts.
- Threaded inserts – wire thread inserts and solid inserts.
- Speed nuts & spring clips – formed from 401 strip.
- Terminals, lugs & special parts – made to your drawing.
Monel 401 Threaded Inserts & Speed Fasteners
Monel 401 threaded inserts give a strong, wear-resistant thread in soft or thin parent materials, and their low magnetic permeability suits electronic housings. Wire inserts are coiled from N04401 wire; solid inserts are machined from rod.
Monel 401 speed fasteners – speed nuts, U-clips and push-on spring clips – are stamped and formed from 401 strip. They give quick, vibration-resistant fastening on panels and sheet-metal assemblies where a non-magnetic, corrosion-resistant part is needed.
For high-strength or load-bearing bolting, use Monel K-500 fasteners or Monel 400 fasteners instead.
Monel 401 Fastener Size Range
| Fastener type | Typical size range | Notes |
| Machine screws | M1.6 – M12 (#0 – ½”) | Metric or UNC / UNF; slotted, Phillips, hex socket |
| Nuts & washers | M1.6 – M16 | Hex, square, lock nuts; flat and spring washers |
| Studs & terminal posts | M2 – M16 | Full or partial thread, to drawing |
| Threaded inserts | M2 – M12 (#2 – ½”) | Wire-coil or solid; free-running or locking |
| Speed nuts & spring clips | From 0.3 – 1.0 mm strip | U-type, J-type, flat and push-on styles |
Typical ranges – other sizes, lengths and special parts on request.
Typical Mechanical Properties of Monel 401
| Condition | Tensile strength | 0.2% yield strength | Hardness |
| Annealed | 345 – 414 MPa (50 – 60 ksi) | 207 – 276 MPa (30 – 40 ksi) | HRB 60 – 75 |
| Cold-worked (tempers) | Higher, up to about 830 MPa (120 ksi) max | Increases with cold work | To temper ordered |
Typical values for N04401 wire and strip – there is no ASTM minimum for 401 fasteners. Actual values are reported on the certificate for each lot.
Specifications for UNS N04401 Fasteners
| Item | Details |
| Alloy | Monel 401, UNS N04401 (Ni-Cu, 40–45% Ni) |
| Raw material | Wire, rod and strip; DIN 17471 resistance-alloy designations for strip and wire |
| Fastener specification | None for N04401 – supplied to customer drawing |
| Dimensions | ISO / DIN / ASME B18 where applicable, or to drawing |
| Not covered by | ASTM F467 / F468 (these cover Monel 400, 405 and K-500 only) |
| Certificate | EN 10204 3.1; third-party inspection on request |
Chemical Composition of Monel 401 (UNS N04401)
| Element | Composition (wt %) |
| Nickel (Ni) + Cobalt | 40.0 – 45.0 |
| Copper (Cu) | Balance |
| Manganese (Mn) | 2.25 max |
| Iron (Fe) | 0.75 max |
| Cobalt (Co) | 0.25 max |
| Silicon (Si) | 0.25 max |
| Carbon (C) | 0.10 max |
| Sulphur (S) | 0.015 max |
Physical Properties of Monel 401
| Property (approx.) | Value |
| Density | 8.88 g/cm³ |
| Electrical resistivity (20 °C) | ≈ 0.49 µΩ·m (49 µΩ·cm) |
| Magnetic | Practically non-magnetic (permeability ≈ 1) |
| Thermal conductivity | ≈ 21 W/m·K |
| Thermal expansion (20–100 °C) | ≈ 13.7 µm/m·°C |
| Modulus of elasticity | ≈ 179 GPa |
| Melting point | ≈ 1,280 – 1,315 °C |
Applications of Monel 401 Fasteners
| Industry | Typical Monel 401 fastener uses |
| Electrical & electronics | Resistor terminals and mounting screws, contact hardware, instrument assemblies |
| Instrumentation & sensors | Low-magnetic screws, nuts and threaded inserts near sensitive components |
| Panels & enclosures | Speed nuts and spring clips on sheet-metal and electronic housings |
| General corrosion service | Small fasteners in mildly corrosive or humid environments |
For seawater, offshore and high-load bolting, Monel 400 or K-500 is the correct choice – see all Monel fasteners.
Quality Assurance at ASC LLP
Every lot of Monel 401 fasteners is checked before dispatch:
- Positive material identification (PMI) of N04401 chemistry
- Dimensional and thread gauge inspection
- Hardness testing; tensile testing of raw material
- Visual inspection and clean, segregated packing
Material test certificates are supplied to EN 10204 3.1, or 3.2 with third-party inspection, with full heat traceability.
Monel 401 vs 400 vs 405 vs K-500 Fasteners
| Grade | Nickel | Fastener standard | Best for |
| Monel 401 (N04401) | 40 – 45% | None – to drawing | Electrical and electronic hardware, threaded inserts, clips |
| Monel 400 (N04400) | 63% min | ASTM F467 / F468 | General corrosion-resistant bolting, seawater |
| Monel 405 (N04405) | 63% min | ASTM F467 / F468 | Free-machining nuts and screws |
| Monel K-500 (N05500) | 63 – 70% | ASTM F467 / F468 Grade 500 | High-strength subsea and pump bolting |
Why Choose ASC LLP for Monel 401 Fasteners?
- The right grade: genuine N04401 material, certified and traceable – not Monel 400 relabelled as 401.
- Supplied to drawing: screws, nuts, inserts, clips and special parts in small or large quantities.
- Full Monel range: 400, 405, R-405, K-500 and 401 fasteners from one supplier.
- Export packing and documentation for worldwide shipment.
Send drawing, size, quantity and grade to sales@amardeepsteel.com or call 022-67439130.
Frequently Asked Questions – Monel 401 Fasteners
What is Monel 401?
Monel 401 (UNS N04401) is a nickel-copper alloy with 40–45% nickel and the balance copper. It has more copper than Monel 400, which gives it stable electrical resistivity and very low magnetic permeability, and it is used mainly for electrical and electronic components.
Which ASTM standard covers Monel 401 fasteners?
None. ASTM F467 and F468 cover Monel 400, 405 and K-500 fasteners, but not N04401. Monel 401 fasteners are supplied to the customer drawing, with dimensions to ISO, DIN or ASME B18 where applicable.
What is the difference between Monel 401 and Monel 400?
Monel 400 contains at least 63% nickel and is the standard Ni-Cu alloy for corrosion-resistant piping and bolting. Monel 401 contains only 40–45% nickel and more copper, and is chosen for its electrical properties rather than for strength.
Is Monel 401 magnetic?
No. Monel 401 is practically non-magnetic, with a magnetic permeability close to 1, which is one reason it is used near sensitive electronic and instrument components.
Can you supply Monel 401 threaded inserts and speed nuts?
Yes. Wire thread inserts can be coiled from N04401 wire, solid inserts machined from rod, and speed nuts and spring clips formed from 401 strip – all to your drawing with 3.1 certificates.
Can Monel 401 be heat-treated for higher strength?
No. Monel 401 is not age-hardenable. Its strength is increased only by cold working; for high-strength fasteners Monel K-500 is used.
Global Reach
ASC LLP supplies Monel and other nickel-alloy fasteners to customers in the USA, Europe, the Middle East and Asia, with secure packing and full documentation. Buyers worldwide rely on our Monel 401 fasteners for certified material and traceability.
Countries We Export To
UNITED STATES, EUROPE, UK, UAE, SAUDI ARABIA, OMAN, KUWAIT, JORDAN, QATAR, INDONESIA, MALAYSIA, BRAZIL, SPAIN, ITALY, FRANCE, GERMANY, BAHRAIN, SRI LANKA, AZERBAIJAN, AUSTRALIA, AUSTRIA, PHILIPPINES, TURKEY, RUSSIA, IRAN, IRAQ, CANADA, KOREA, JAPAN, YEMEN, FINLAND, ZIMBABWE, HUNGARY, PORTUGAL, VIETNAM, MOROCCO, THAILAND, SOUTH AFRICA, MEXICO, SINGAPORE, GREECE, KUWAIT, POLAND, NEW ZEALAND, SWEDEN, SWITZERLAND, BELGIUM, BHUTAN, BANGLADESH, TAIWAN, ROMANIA, CAMBODIA, KAZAKHSTAN, AFGHANISTAN.
