Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
Alloy 401 is a nickel–copper alloy designed specifically for specialised electrical and electronic applications. This datasheet presents the material within the American (UNS) standard system.
Unlike the nickel-rich Monel 400 (~67% Ni), alloy 401 is copper-rich: it contains 43–45% nickel-plus-cobalt with the balance copper, a composition chosen to give a very low temperature coefficient of resistance combined with a medium-range electrical resistivity. These characteristics, together with good corrosion resistance across a wide variety of environments, make it well suited to wire-wound precision resistors, bi-metal contacts, resistance heaters and circuits.
It is a ductile, single-phase alloy that, like commercially pure nickel, is low in strength in the annealed condition and is strengthened only by cold work (it does not respond to heat treatment). Standard product forms are strip and wire, in which thin sections it is most often used. It is readily autogenously welded by the gas-tungsten-arc process, joined well by resistance welding, and exhibits good brazing characteristics.
Values per manufacturer (Special Metals / Ulbrich) data, annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 8.88 | g/cm³ |
| Melting point (approx.) | 1280 | °C |
| Young's modulus (20 °C) | 179 | GPa |
| Thermal conductivity (21 °C) | 21.0 | W/m·K |
| Electrical resistivity (20 °C) | medium-range (~0.49) | µΩ·m |
| Temperature coefficient of resistance | Very low | — |
| Coefficient of thermal expansion (20–95 °C) | 13.7 | µm/m·°C |
| Magnetic response | Slightly magnetic / near non-magnetic | — |
| Standard product forms | Strip and wire | — |
Limiting composition per manufacturer specification (UNS N04401).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Copper | Cu | Balance | — | Base element (copper-rich, ~53%); electrical properties |
| Nickel (+ Cobalt) | Ni+Co | 43.0 | 45.0 | Controlled level for low TCR + corrosion resistance |
| Manganese | Mn | — | 2.25 | Deoxidiser |
| Iron | Fe | — | 0.75 | Residual |
| Cobalt | Co | — | 0.25 | Residual (counted with Ni) |
| Carbon | C | — | 0.10 | Controlled |
| Silicon | Si | — | 0.25 | Deoxidiser |
| Sulphur | S | — | 0.015 | Residual impurity |
Note: alloy 401 is copper-rich (the balance is copper, ~53%), distinct from the nickel-rich Monel 400. The controlled 43–45% Ni+Co level is what gives the low temperature coefficient of resistance for electrical use.
Typical room-temperature properties.
| Property | Value | Source |
|---|---|---|
| Ultimate tensile strength (annealed) | ~415–550 MPa | Annealed (low strength) |
| Ultimate tensile strength (cold-worked) | up to ~827 MPa (120 ksi) | Cold-worked maximum |
| Elongation (annealed) | ~30–40 % | Annealed |
| Condition | Strengthened by cold work only | Not heat-treatable |
Like commercially pure nickel, alloy 401 is low in strength in the annealed condition and can be cold-worked to a maximum of about 120 ksi. It is not hardenable by heat treatment. Values are typical; confirm against the mill test certificate for each delivery.
| Environment | Performance | Notes |
|---|---|---|
| General corrosive conditions | Very Good | Resistant to a wide variety of environments |
| Seawater / marine | Good | Ni-Cu base (copper-rich) |
| Alkalis / salts | Good | Broad resistance |
| Reducing acids | Good | Non-oxidising conditions |
| Atmospheric / mild media | Excellent | Stable Ni-Cu surface |
| Oxidising media (nitric acid) | Poor | No chromium — avoid |
Note: alloy 401 is selected primarily for its electrical properties; its corrosion resistance is good across many environments but it is not a primary corrosion-service alloy like Monel 400.
A single-phase nickel–copper alloy; not hardenable by heat treatment. Heat treatment is for annealing only; strengthening is by cold work.
Anneal Temperature: typical Ni-Cu annealing range, followed by appropriate cooling Purpose: softening and restoration of ductility after cold work.
The alloy may be hot-worked if required, and is readily cold-worked using standard tooling (soft die materials give a better finish). Strength is developed by cold work, not by aging.
Readily joined, particularly in the thin sections in which it is most often used. Gas-tungsten-arc (GTAW) autogenous welding is the common procedure; resistance welding is very satisfactory; and the alloy brazes well.
| Welding Process | Applicability | Notes |
|---|---|---|
| GTAW / TIG (autogenous) | Excellent | Common method for thin strip/wire |
| Resistance welding | Excellent | Very satisfactory for this alloy |
| Brazing / soldering | Good | Good brazing characteristics |
Keep joints clean. As the alloy is usually supplied as fine strip and wire, thin-section joining methods predominate.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machining | Conventional techniques used for iron alloys are applicable |
| Cold working | Standard tooling; soft die materials for better finish |
| Hot working | May be hot-worked if needed |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Readily cold-worked; strengthens by cold work |
| Hot forming | Possible if required |
| Product forms | Usually strip, foil, ribbon and wire |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Electrical / electronic | Wire-wound precision resistors | Low temperature coefficient of resistance |
| Electrical / electronic | Bi-metal contacts | Electrical + corrosion properties |
| Electrical | Resistance heaters and circuits | Medium-range resistivity |
| Electronics | Fine strip, foil and wire components | Stable electrical behaviour |
Note: alloy 401 is a specialised electrical/electronic material; for marine and chemical corrosion service the nickel-rich Monel 400 is the appropriate grade.
| Product Form | Standard / Reference |
|---|---|
| Wire (round, flat, square, profile) | Primary form; UNS N04401 |
| Strip, foil and ribbon | Primary form |
| Bar, rod and other forms | On request |
| Welding | Autogenous GTAW; resistance welding; brazing |
Specialised electrical/electronic nickel-copper alloy. UNS N04401. Standard product forms are strip and wire; other forms on request. Not hardenable by heat treatment.
| Alloy | Ni % | Key Feature | Type | Best Used For |
|---|---|---|---|---|
| Alloy 401 | 43–45 (Ni+Co) | Cu-rich (bal Cu) | Electrical Ni-Cu | Precision resistors; bi-metal contacts |
| Alloy 400 | 63–70 | Ni-rich (~30 Cu) | Solid-solution Ni-Cu | Seawater, HF, reducing acids |
| Alloy R-405 | 63–70 | S free-machining | Free-machining Ni-Cu | Screw-machine stock |
| Alloy K-500 | 63–70 | Al+Ti age-hard. | Age-hardened Ni-Cu | High strength; non-magnetic |
| Alloy 200 | ≥99.0 | Pure Ni | Commercially pure | Caustic/alkali; conductivity |
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