Monel is a trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

 of Special Metals Corporation
Special Metals Corporation
Special Metals Corporation, headquartered in New Hartford, New York, U.S.A., with operations in Huntington, West Virginia; Dunkirk, New York; Burnaugh, Kentucky; Elkhart, Indiana and Hereford, England, is a supplier of refractory alloys....

 for a series of nickel alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

s, primarily composed of nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

 (up to 67%) and copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, with some iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 and other trace elements. Monel was created by David H. Browne, chief metallurgist for International Nickel Co. Monel alloy 400 is binary alloy of the same proportions of nickel and copper as is found naturally in the nickel ore from the Sudbury (Ontario) mines. Monel was named for company president Ambrose Monell, and patented in 1906. One L was dropped, because family names were not allowed as trademarks at that time.


Compared to steel, Monel is very difficult to machine as it work-hardens very quickly. It needs to be turned and worked at slow speeds and low feed rates. It is resistant to corrosion and acids, and some alloys can withstand a fire in pure oxygen. It is commonly used in applications with highly corrosive conditions. Small additions of aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 and titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 form an alloy (K-500) with the same corrosion resistance but with much greater strength due to gamma prime formation on aging. Monel is typically much more expensive than stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....


Monel alloy 400 has a specific gravity of 8.83, an electrical conductivity of approximately 3.4% IACS
IACS may refer to:* Integrated Administration and Control System* Indian Association for the Cultivation of Science* International Annealed Copper Standard, a unit of electrical conductivity for metals and alloys relative to a standard annealed copper conductor; an IACS value of 100% refers to a...

, and (in the annealed state) a hardness of 65 Rockwell B.

Aerospace applications

In the 1960s, Monel metal found bulk uses in aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 construction, especially in making the frames and skins of experimental
Experimental aircraft
An experimental aircraft is an aircraft that has not yet been fully proven in flight. Often, this implies that new aerospace technologies are being tested on the aircraft, though the label is more broad....

 rocket planes, such as the North American X-15
North American X-15
The North American X-15 rocket-powered aircraft/spaceplane was part of the X-series of experimental aircraft, initiated with the Bell X-1, that were made for the USAAF/USAF, NACA/NASA, and the USN. The X-15 set speed and altitude records in the early 1960s, reaching the edge of outer space and...

, to resist the great heat generated by aerodynamic friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...

 during extremely high speed flight. Monel metal retains its strength at very high temperatures, allowing it to maintain its shape at high atmospheric flight speeds, a trade off against the increased weight of the parts due to Monel's high density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...


Marine applications

Monel's corrosion resistance makes it ideal for marine applications such as piping systems, pump shafts, seawater valves, trolling wire, and strainer baskets. Some alloys are completely non-magnetic and are used for anchor cable aboard minesweepers
Minesweeper (ship)
A minesweeper is a small naval warship designed to counter the threat posed by naval mines. Minesweepers generally detect then neutralize mines in advance of other naval operations.-History:...

, housings for magnetic-field measurement equipment. In recreational boating, Monel wire is used to seize shackles for anchor rodes, Monel is used for water and fuel tanks, and for under water applications. It is also used for propeller shafts and for keel bolts.

However, because of the problem of electrolytic action in salt water (also known as Galvanic corrosion), in shipbuilding monel must be carefully insulated from other metals such as steel. The New York Times of August 12, 1915 published an article about a 215 foot yacht, "the first ship that has ever been built with an entirely monel hull," that "went to pieces" in just six weeks and had to be scrapped, "on account of the disintegration of her bottom by electrical action." The yacht's steel skeleton deteriorated due to electrolytic interaction with the monel.

In seabird research, and bird banding or ringing in particular, Monel has been used to make bird bands or rings for many species such as albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...

 that live in a corrosive sea water environment.

Monel is also used for safety wiring in the aircraft industry to ensure that fasteners cannot come undone.

Musical instruments

Monel is used as the material for valve pistons in some higher quality musical instruments such as trumpets, tubas and French horn rotors. RotoSound
-History of Rotosound:Started in the late 1950's by James How -a musician and engineer by trade. How started manufacturing music strings for many famous artists across the world. Still a family run business all Rotosound strings are made in England....

 introduced the use of Monel for electric bass
Bass guitar
The bass guitar is a stringed instrument played primarily with the fingers or thumb , or by using a pick....

 strings in 1962, and these strings have been used by numerous artists, including Steve Harris
Steve Harris (musician)
Stephen Percy "Steve" Harris is an English musician and songwriter, known as the bassist, occasional keyboardist, backing vocalist and primary songwriter of the British heavy metal band Iron Maiden, which he founded in 1975...

 of Iron Maiden
Iron Maiden
Iron Maiden are an English heavy metal band from Leyton in east London, formed in 1975 by bassist and primary songwriter Steve Harris. Since their inception, the band's discography has grown to include a total of thirty-six albums: fifteen studio albums; eleven live albums; four EPs; and six...

, The Who
The Who
The Who are an English rock band formed in 1964 by Roger Daltrey , Pete Townshend , John Entwistle and Keith Moon . They became known for energetic live performances which often included instrument destruction...

, Sting, John Deacon
John Deacon
John Richard Deacon is a retired English multi-instrumentalist and song writer, best known as the bassist for the rock band Queen. Of the four members of the band, he was the last to join and also the youngest, being only 19 years old when he was recruited by the other members of the band...

, and John Paul Jones
John Paul Jones (musician)
John Paul Jones is an English multi-instrumentalist, songwriter, composer, arranger and record producer. Best known as the bassist, mandolinist, and keyboardist for English rock band Led Zeppelin, Jones has since developed a solo career and has gained even more respect as both a musician and a...

. Monel was in use in the early 1930s by other musical string manufacturers, such as Gibson Guitar Corporation
Gibson Guitar Corporation
The Gibson Guitar Corporation, formerly of Kalamazoo, Michigan and currently of Nashville, Tennessee, manufactures guitars and other instruments which sell under a variety of brand names...

, who continue to offer them for mandolin as the Sam Bush
Sam Bush
Sam Bush is an American bluegrass mandolin player considered an originator of the Newgrass style.- History :...

 signature set.

Directional Drilling

Monel drill collars are used in surveying oil wells. Monel collars are used in drilling directional wells which require the well to be steered. Their use permits faster and more accurate surveys, reduce hazards, and decreases the cost of drilling directional of controlled oil wells. The reduced cost comes from the ability of real time surveys from a MWD
Measurement While Drilling
MWD stands for Measurement While Drilling in the oil & gas industry. The simplest way to describe MWD is to relate it to the measurements a pilot takes. A pilot needs to know the direction they are flying , the angle they are fly at , and what type of skies they will be flying through...

 tool which has magnetometers built into them. The magnetometers if not surrounded by non-magnetic material (monel, inconel, Cu-Be, or non-magnetic stainless) will be unable to read the earth’s magnetic field without interference and will give an incorrect reading.

Monel is very rarely used in present day directional drilling collars. They are still referred to as monel collars based on tradition and misinformation. Monel has been substituted with 316 and other non-magnetic stainless materials due to cost.


The good resistance against corrosion by acids and oxygen makes monel a good material for the chemical industry. Even corrosive fluorides can be handled within monel apparatus; this was done in an extensive way in the enrichment of uranium in the Oak Ridge Gaseous Diffusion Plant
K-25 is a former uranium enrichment facility of the Manhattan Project which used the gaseous diffusion method. The plant is located in Oak Ridge, Tennessee, on the southwestern end of the Oak Ridge Reservation.-History:...

. Here most of the larger diameter tubing for the uranium hexafluoride
Uranium hexafluoride
Uranium hexafluoride , referred to as "hex" in the nuclear industry, is a compound used in the uranium enrichment process that produces fuel for nuclear reactors and nuclear weapons. It forms solid grey crystals at standard temperature and pressure , is highly toxic, reacts violently with water...

 was made from monel. Regulators for reactive cylinder gases like hydrogen chloride
Hydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...

 form another example, where PTFE is not a suitable option when high delivery pressures are required. These will sometimes include a Monel manifold and taps prior to the regulator that allow the regulator to be flushed with a dry, inert gas after use to further protect the equipment.

Monel was used for US Military dog tags
Dog tag (identifier)
A dog tag is the informal name for the identification tags worn by military personnel, named such as it bears resemblance to actual dog tags. The tag is primarily used for the identification of dead and wounded and essential basic medical information for the treatment of the latter, such as blood...

 in WWI and WWII.
Monel is often used for kitchen sinks and in the frames of eyeglasses. It has also been used for firebox stays in fire-tube boiler
Fire-tube boiler
A fire-tube boiler is a type of boiler in which hot gases from a fire pass through one or more tubes running through a sealed container of water...


Parts of the Clock of the Long Now
Clock of the Long Now
The Clock of the Long Now, also called the 10,000-year clock, is a proposed mechanical clock designed to keep time for 10,000 years. The project to build it is part of the Long Now Foundation....

, which is intended to run for 10,000 years, are made from Monel because of the corrosion resistance without the use of precious metals.

Monel was used for much of the exposed metal used in the interior of the Bryn Athyn Cathedral
Bryn Athyn Cathedral
Bryn Athyn Cathedral is the episcopal seat of The General Church of the New Jerusalem, a denomination of "The New Church." The main building is of the Early Gothic style, while the adjoining structures are of a transitional period reflective of a combination of both Gothic and Norman styles...

. This included large decorative screens, doorknobs, etc. Monel also has been used as roofing material in buildings such as the original Pennsylvania Station in New York City.
The 1991 - 1996 Acura (Honda) NSX came with a key made of Monel.

Oilfield applications include using Monel (rarely - see directional drilling above) in both flex and slick collars. Instruments (magnetometers or compass) which measure the Earth's magnetic field to obtain a magnetic direction are placed in the non-magnetic collar which isolates sensors from the magnetic pull of drilling tools located above and below the non-magnetic collars. They are often referred to as "monel collars" as that was the first material used to make the collars and the name stuck.

Monel is also used as a protective binding material on the outside of western style stirrups.

Monel is used to by Arrow Fastener Co., Inc. for rustproof T50 staples.


Trade Name ASME P Group ASTM/AISI
American Iron and Steel Institute
The American Iron and Steel Institute is an association of North American steel producers. Its predecessor organizations date back to 1855 making it one of the oldest trade associations in the United States. AISI assumed its present form in 1908, with Elbert H...

Steel type
Unified numbering system
The unified numbering system is an alloy designation system widely accepted in North America. It consists of a prefix letter and five digits designating a material composition. A prefix of S indicates stainless steel alloys, C for copper, brass, or bronze alloys, T for tool steels, etc...

Monel 400 B 127, B 164 N04400
Monel 401 N04401
Monel 404 B 164 N04404
Monel K-500 B 865 N05500
Monel R-405 N04405

External links

  • Monel Corrosion
  • Hastelloy
    Hastelloy is the registered trademark name of Haynes International, Inc. The trademark is applied as the prefix name of a range of twenty two different highly corrosion-resistant metal alloys loosely grouped by the metallurgical industry under the material term “superalloys” or “high-performance...

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