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Monel 400 Nickel-Copper Based Alloy
Monel 400 is a nickel-copper alloy that has corrosion resistance in many environments, and Monel alloy is very strong. It consists of two crystalline solids forming a single new solid.
Monel is the brainchild of Robert Crooks Stanley of International Nickel Corporation. It was patented in 1906 and named after the company's president Ambrose Monell. The second "L" was deleted from the metal name because it was not possible to apply for a patent on a person's name at that time.
There are many variants of Monel alloy, starting with Monel 400, the alloy contains at least 63% nickel, 29% to 34% copper, 2% to 2.5% iron, and 1.5% to 2% manganese. The silicon content of Monel 405 does not exceed 0.5%, the aluminum content of Monel K-500 is between 2.3% and 3.15%, and the content of titanium is between 0.35% and 0.85%. These and other changes are valued for their resistance to acids and alkalis, as well as their high mechanical strength and good ductility. Monel 400 has high strength and can only be hardened by cold working. Due to its aging resistance, Monel 400 is most commonly used for parts in marine and chemical environments.
Although it is a very useful metal, it is very costly in most applications. The price of Monel 400 is 5 to 10 times that of ordinary nickel or copper. As a result, it is rarely used and only used when no other metal can meet the same requirements. For example, Monel 400 is one of the few alloys that can maintain strength at sub-zero temperatures, so Monel 400 can be used in these situations.
The standard components of Monel 400 are mainly nickel and copper, including:
Nickel (plus cobalt): minimum 63%Carbon: up to 0.3%
Manganese: 2.0% max
Fe: 2.5% max
Sulfur: 0.024% max
Silicon: up to 0.5%
Copper: 29-34%
Performance of nickel-copper alloy Monel 400
Density: 8.80 g/cm3Modulus of Elasticity: 179 gallons
Thermal expansion (20oC): 13.9×10 -6 oC-1 7.7
Specific heat capacity: 427 J (kg K)
Thermal conductivity: 21.8 watts (m K)
Resistivity: 54.7 10 -8 ohm meters
Tensile strength (annealed): 550 MPa
Yield strength (annealing): 240 MPa
Elongation: 48%
Liquidus temperature: 1,350oC
Solidus temperature: 1,300oC
Manufacturing of Monel 400
Monel 400 alloy hardens during processing. If Monel 400 is to be hardened, the only option is to use soft die material for cold working. Through cold working, mechanical stress instead of heat is used to change the shape of the metal. When thermal processing Monel 400, the temperature range should be 648-1,176 degrees Celsius (1,200-2,150 degrees Fahrenheit). It can be annealed at 926 degrees Celsius (1,700 degrees Fahrenheit).
Monel 400 Application Areas
Due to its acid, alkali, and seawater resistance, Monel 400 is usually used in applications where corrosion may need to be considered. This includes marine environments that require fixtures, valves, pumps and piping systems. Other applications sometimes include chemical plants, including environments where sulfuric acid and hydrofluoric acid are used.Another area where Monel 400 is popular is the eyewear industry. It is one of the most popular materials used for frames, especially components along the temples and bridge of the nose. According to Mo Ju, the combination of strength and corrosion resistance makes it useful for frames. However, the disadvantage is that it is difficult to shape, which limits its use in certain frames.
Monel 400 disadvantages
Although valuable in many applications, Monel 400 is not perfect. Although it can resist corrosion in many ways, it cannot withstand nitric oxide, nitrous acid, sulfur dioxide and hypochlorite. Therefore, Monel 400 should not be used in an environment where it will be exposed to these elements. Monel 400 is also susceptible to electrical corrosion. This means that if aluminum, zinc or iron fasteners are used with Monel 400, they will corrode very quickly.
