Monel is a solid solution alloy that may be hardened only by cold working. It has high strength and toughness over a wide temperature range and excellent resistance to many corrosive environments.
The good resistance against corrosion by acids and oxygen makes monel a good material for the chemical industry. Monel is widely used in many fields, especially marine and chemical processing. Typical applications are valves and pumps; pump and propeller shafts; marine fixtures and fasteners; electrical and electronic components; springs; chemical processing equipment; gasoline and fresh water tanks; crude petroleum stills, process vessels and piping; boiler feed water heaters and other heat exchangers; and deaerating heaters.
Aerospace applications
Monel metal found bulk uses in aircraft construction, especially in making the frames and skins of experimental rocket planes, 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.
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, 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.