Monel R 405 Alloy N04405 Alloy

Monel R 405 Alloy is free-machining version of Monel alloy 400. A controlled amount of sulphur is added to the alloy to provide sulphide inclusions that act as chip breakers during machining. Other characteristics are essentially the same as those of Monel alloy 400. Used for meter and valve parts, fasteners, and screw-machine products.

Like Monel 400, alloy R-405 is resistant to seawater and steam at high temperature as well as to salt and caustic solutions. Monel R405 is a solid solution alloy that can only be hardened by cold working. This nickel alloy exhibits characteristics like good corrosion-resistance, good weldability and high strength.

A low corrosion rate in rapidly flowing brackish or seawater combined with excellent resistance to stress corrosion cracking in most freshwaters, and its resistance to a variety of corrosive conditions led to its wide use in marine applications and other non-oxidizing chloride solutions. This nickel alloy is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. As its high copper content, alloy R-405 is rapidly attacked by nitric acid and ammonia systems.

Monel R 405 Machinability is good. High-speed tool steel should be used with oil base lubricants. Turning is done at speeds of 140-160 surface feet per minute with a feed rate of approximately 0.004 in./revolution. Drilling is done at 50-65 surface feet per min. with feed of 0.003 in./revolution.

Monel R 405 Characteristics

• Corrosion resistance in an extensive range of marine and chemical environments. From pure water to nonoxidizing mineral acids, salts and alkalis.
• This alloy is more resistant to nickel under reducing conditions and more resistant than copper under oxidizing conditions, it does show however better resistance to reducing media than oxidizing.
• Good mechanical properties from subzero temperatures up to about 480C.
• Good resistance to sulfuric acids and hydrofluoric acids. Aeration however will result in increased corrosion rates. 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, but poor resistance is found with oxidizing acid salts such as ferric chloride.
• Excellent resistance to chloride ion stress corrosion cracking.

*Due to sulfur addition for free machining, welding is not possible.

Monel R405 Alloy Specification:

ASME SB163 Standard Specification for Seamless Nickel and Nickel Alloy Condenser and Heat-Exchanger Tubes

ASME SB165 Standard Specification for Nickel-Copper Alloy (UNS N04400)* Seamless Pipe and Tube

ASME SB167 Standard Specification for Nickel-Chromium-Iron Alloys, Nickel-Chromium-Cobalt-Molybdenum Alloy (UNS N06617),and Nickel-Iron-Chromium-Tungsten Alloy (UNS N06674) Seamless Pipe and Tube

ASME SB407 Standard Specification for Nickel-Iron-Chromium Alloy Seamless Pipe and Tube

ASME SB423 Standard Specification for Nickel-Iron-Chromium-Molybdenum-Copper Alloy (UNS N08825, N08221, and N06845) Seamless Pipe and Tube

ASME SB444 Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloys (UNS N06625 and UNS N06852) and Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219) Pipe and Tube

ASME SB622 Standard Specification for Seamless Nickel and Nickel-Cobalt Alloy Pipe and Tube

ASME SB668 UNS N08028 Seamless Pipe and Tube

ASME SB690 Standard Specification for Iron-Nickel-Chromium-Molybdenum Alloys (UNS N08366 and UNS N08367) Seamless Pipe and Tube

ASME SB729 Standard Specification for seamless UNS N08020, UNS N08026, and UNS N08024 nickel alloy pipe and Tube

Monel R 405 Applications

• Feed water and steam generator tubing.
• Brine heaters, sea water scrubbers in tanker inert gas systems.
• Sulfuric acid and hydrofluoric acid alkylation plants.
• Pickling bat heating coils.
• Heat exchanger in a variety of industries.
• Transfer piping from oil refinery crude columns.
• Plant for the refining of uranium and isotope separation in the production of nuclear fuel.
• 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

Corrosion Resistant Monel R-405

As with alloy 400, Monel R-405 is virtually immune to chloride ion stress corrosion cracking in typical environments. Generally, its corrosion resistance is very good in reducing environments, but poor in oxidizing conditions. It is not useful in oxidizing acids, such as nitric acid and nitrous. Nevertheless, it is resistant to most alkalis, salts, waters, food products, organic substances and atmospheric conditions at normal and elevated temperatures.

Monel 400 and R-405 offer about the same corrosion resistance as nickel but with higher maximum working pressure and temperatures and at a lower cost due to its superior ability to be machined.

Chemical Composition, %

Fabrication with Monel R-405

Monel R-405 is fabricated, pickled and heat-treated by the same procedures as for alloy 400. It is not recommended for forging. However, R-405 alloy was especially developed for good machinability and is recommended for use with automatic screw machines. The nickel –copper sulfides resulting from the sulfur in its composition act as chip breakers.

This nickel alloy also has the same procedures and processes as alloy 400 and can be joined by standard welding, brazing and soldering techniques. Just as with alloy 400, R-405 can easily be welded by gas – tungsten arc, gas metal arc, or shielded metal arc processes using appropriate filler metals. There is no need for post weld heat treatment, however, thorough cleaning after welding is critical for optimum corrosion resistance, otherwise there is the risk of contamination and embrittlement.

Monel R 405 Mechanical Properties 
Nominal Mechanical Property Range of Monel Alloy R-405 Rod and Bar

The ranges shown are composites for various product sizes and therefore are not suitable for specification purposes.