Monel® 400

Monel® 400 - UNS N04400 - W. Nr. 2.4360 - Nickel Alloy 400 - NiCu Alloy

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Table of Contents
Datasheet Chemistry
Inventory Applications
General Data Mechanical Properties
Specifications Machining, Welding, & Processing

As a nickel-copper alloy, alloy 400 has excellent corrosion resistance in a wide variety of media. This alloy is highly resistant to sea water and steam at high temperatures as well as to salt and caustic solutions. Alloy 400 is characterized by its general corrosion resistance, good weldability, and moderate to high strength in the tempered conditions.

This alloy has excellent resistance to rapidly flowing and warm seawater, brackish water, and steam. It is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. This alloy is slightly magnetic at room temperature. Alloy 400 is widely used in the chemical, oil, and marine engineering industries. For the more machinable variant, please see alloy R405.


View or download Special Metals' Monel® 400 datasheet here


Min% Max%
Ni (+Co) 63.0
Cu 28.0 34.0
C 0.3
Mn 2.0
Fe 2.5
S 0.024
Si 0.5
*Composition information provided by Special Metals' datasheet on Monel® 400, available here.

Typical Inventory

Round Bar, Plate, Tubing, Pipe, Flange


  • Feed water and steam generator tubing.
  • Brine heaters, sea water scrubbers in tanker inert gas systems.
  • Sulfuric acid and hydrofluoric acid alkylation plants.
  • Pickling bath heating coils.
  • Heat exchangers in a variety of industries.
  • Transfer piping from oil refinery crude columns.
  • Pumps and valves used in the manufacture of perchlorethylene, chlorinated plastics.
  • Monoethanolamine (MEA) reboiling tube.
  • Cladding for the upper areas of oil refinery crude columns.
  • Propeller and pump shafts.

General Data

  • Alloy 400 displays strong corrosion resistance in an extensive range of marine and chemical environments, including those containing pure water, nonoxidizing mineral acids, salts and alkalis.
  • This alloy is more resistant than pure nickel under reducing conditions and more resistant than pure copper under oxidizing conditions.
  • Alloy 400 displays good mechanical properties - even in environments with subzero temperatures up to about 480 °C.
  • Alloy 400 shows good resistance to sulfuric and hydrofluoric acids. Aeration however will result in increased corrosion rates. This alloy may be used to handle hydrochloric acid, but the presence of oxidizing salts will greatly accelerate corrosive attack.
  • Resistance to neutral alkaline and acid salts is shown in Alloy 400, but the alloy displays poor resistance with oxidizing acid salts ,such as ferric chloride.
  • Alloy 400 has excellent resistance to chloride ion stress corrosion cracking.

Mechanical Properties

The typical properties listed can usually be provided in rounds, sheet, strip, plate, & custom forgings. We have the equipment to produce small quantities in special sizes to meet our customers’ specific needs. The table below shows Special Metals' Nominal Mechanical Property Range of MONEL® Alloy 400 Rod and Bar. For most common forms and exceptions, check out the datasheet linked underneath the table.

Cond. Ultimate Tensile ksi (MPa) Yield Strength ksi (MPa) Elong. % in 2 in. Rockwell Hardness
Anneal 75-90 (517-620) 25-50 (172-345) 60-35 60-80B
Hot-Finished 80-110 (552-758) 40-100 (276-690) 60-30 75-100B
Cold-Drawn, Stress-Relieved 84-120 (579-827) 55-100 (379-690) 40-22 85B-20C
Link to Special Metals' datasheet on alloy 400

Common Specifications

Note that the specifications listed are common for this alloy but are for reference only and may be specific to a certain form. The specifications listed are not comprehensive nor indicative of any edition, revision, or similar such as an amendment. Please, reach out to our sales department to request the Material Test Report (MTR) or to confirm your required specifications.

Form Standard
Identification UNS N04400, DIN 17743, DIN 17750 – 17754, W. Nr. 2.4360
Bar AMS 4675, ASTM B164, ASTM B564, ASME SB164, ASME SB564, QQ-N-281
Wire AMS 4730
Sheet, Plate, or Strip AMS 4544, ASTM B127, ASME SB127, QQ-N-281
Pipe - Seamless ASTM B165, ASME SB165
Pipe - Welded ASTM B725, ASTM B751, ASME SB730, ASME SB751
Tube - Seamless AMS 4574, ASTM B165, ASME SB165
Tube - Welded ASTM B730, ASTM B751, ASME SB730, ASME SB751
Tube - Brazed AMS 4575
Fitting ASTM B366, ASME SB366
Forging AMS 4675, ASTM B564, ASME SB564
Weld Wire Monel® FM 60/ UNS N04060/ W. Nr. 2.4377/ AWS A5.14 ERNiCu-7/ ASME IX F-No. 42
Weld Electrode Monel® FM 190/ UNS W84190/ W. Nr. 2.4366/ AWS A5.11 ENiCu-7/ ASME IX F-No. 42
Others NACE MR-0175, ISO 15156


Nickel and cobalt based alloys can be difficult to machinine. However, it should be emphasized that these alloys can be machined using conventional production methods at satisfactory rates. These alloys harden rapidly, generate high heat during cutting, weld to the cutting tool surface and offer high resistance to metal removal because of their high shear strengths. The following are key points which should be considered during machining operations:

  • CAPACITY - Machine should be rigid and overpowered as much as possible.
  • RIGIDITY - Work piece and tool should be held rigid. Minimize tool overhang.
  • TOOL SHARPNESS - Make sure tools are sharp at all times. Change to sharpened tools at regular intervals rather than out of necessity. A 0.015 inch wear land is considered a dull tool.
  • TOOLS - Use positive rake angle tools for most machining operations. Negative rake angle tools can be considered for intermittent cuts and heavy stock removal. Carbide-tipped tools are suggested for most applications. High speed tools can be used, with lower production rates, and are often recommended for intermittent cuts.
  • POSITIVE CUTS - Use heavy, constant, feeds to maintain positive cutting action. If feed slows and the tool dwells in the cut, work hardening occurs, tool life deteriorates and close tolerances are impossible.
  • LUBRICATION - lubricants are desirable. Soluble oils are recommended especially when using carbide tooling.


Link to Special Metals' datasheet on Monel® 400

Monel® is a registered trademark of the Special Metals Corporation group of companies.

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