Monel® R-405

Monel® R-405 - UNS N04405 - W. Nr. 2.4361 - Nickel Alloy R405 - NiCu Alloy

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

As a version of nickel copper alloy 400, alloy R405 has excellent corrosion resistance in a wide variety of media. Alloy R405 is characterized by its general corrosion resistance and moderate to high strength. This alloy is highly resistant to sea water and steam at high temperatures as well as to salt and caustic solutions.

The addition of sulfur to the chemical composition allows for better machining over alloy 400. The alloy has been used in a variety of applications. It 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 R405 is widely used in the chemical, oil, and marine engineering industries.


View or download Special Metals' Monel® R-405 datasheet here


Min% Max%
Ni (+Co) 63.0
Cu 28.0 34.0
C 0.3
Mn 2.0
Fe 2.5
S 0.025 0.060
Si 0.5
*Composition information provided by Special Metals' datasheet on alloy R-405, available here.

Typical Inventory

Round Bar, Plate


  • 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 R405 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 R405 displays good mechanical properties - even in environments with subzero temperatures up to about 480 °C.
  • Alloy R405 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 R405, but the alloy displays poor resistance with oxidizing acid salts ,such as ferric chloride.
  • Alloy R405 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 R-405 Rod and Bar. For most common forms and exceptions, check out the linked datasheet underneath the table.

Cond. Ultimate Tensile ksi (MPa) Yield Strength ksi (MPa) Elong. % in 2 in. Rockwell Hardness
Anneal 70-85 (482-586) 25-40 (172-275) 50-35 60-76B
Hot-Finished 75-90 (517-620) 35-60 (241-413) 45-30 72-86B
Cold-Drawn, As-Drawn 85-115 (586-792) 50-105 (344-723) 35-15 85B-23C
Link to Special Metals' datasheet on alloy R-405

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 N04405, W. Nr. 2.4361
Bar AMS 4674, ASTM B164, ASME SB164, QQ-N-281
Sheet, Plate, or Strip ASTM B127, ASME SB127, QQ-N-281
Forging AMS 4674, ASTM B564, ASMESB564
Weld Electrode Monel® FM 190/ UNS W84190/ W. Nr. 2.4366/ AWS A5.11 ENiCu-7/ ASME IX F-No. 42


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® R-405

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