In the 1960s, Monel metal found bulk uses in aircraft construction, especially in making the frames and skins of experimental rocket planes, such as the North American X-15, to resist the great heat generated by aerodynamic 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.
Monel is used for safety wiring in the aircraft maintenance to ensure that fasteners cannot come undone, usually in high-temperature areas; stainless wire is used in other areas for economy.
Oil production and refining
Monel is used in the section of Alkylation units in direct contact with concentrated hydrofluoric acid. Monel offers exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point. It is perhaps the most resistant of all commonly used engineering alloys. The alloy is also resistant to many forms of sulfuric and hydrochloric acids under reducing conditions.
Monel’s corrosion resistance makes it ideal in 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, housings for magnetic-field measurement equipment. In recreational boating, Monel wire is used to seize shackles for anchor ropes, Monel is used for water and fuel tanks, and for underwater applications. It is also used for propeller shafts and for keel bolts. On the popular Hobiecat sailboats, Monel rivets are used where strength is needed but stainless steel cannot be used due to corrosion problems that would result from having stainless steel in contact with the aluminum mast, boom, and frame of the boat, in a saltwater environment.
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 on 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 that live in a corrosive sea water environment.
Monel is used as the material for valve pistons or rotors in some higher quality musical instruments such as trumpets, tubas and French horns. RotoSound introduced the use of Monel for electric bass strings in 1962, and these strings have been used by numerous artists, including Steve Harris of Iron Maiden, The Who, Sting, John Deacon, John Paul Jones and the late Chris Squire. Monel was in use in the early 1930s by other musical string manufacturers, such as Gibson Guitar Corporation, who continue to offer them for mandolin as the Sam Bush signature set. Also, C.F. Martin & Co. uses Monel for their Martin Retro acoustic guitar strings. The Pyramid string factory (Germany) produces ‘Monel classics’ electric guitar strings, wound on a round core. In 2017, D’Addario string company released a line of violin strings using a Monel winding on the D and G string.
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. Here most of the larger diameter tubing for the uranium hexafluoride was made from Monel. Regulators for reactive cylinder gases like hydrogen chloride 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.
In the early 20th century, when steam power was widely used, Monel was advertised as being desirable for use in superheated steam systems. During the world wars, Monel was used for US military dog tags.
Monel doorknobs in the Bryn Athyn Cathedral
Monel is often used for kitchen sinks and in the frames of eyeglasses. It has also been used for firebox stays in fire-tube boilers.
Parts of the Clock of the Long Now, 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 in Pennsylvania, religious seat of the General Church of the New Jerusalem. 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 greenish roof of Pennsylvania Station was made from monel
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 by Arrow Fastener Co., Inc. for rustproof T50 staples.
Monel has also been used in Kelvinator refrigerators.
Monel was used in the Baby Alice Thumb Guard, a 1930s-era anti-thumb-sucking device.
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