Alloy 400

Introduction :

Monel 400 is a nickel-copper alloy that is resistant to corrosion in many environments. It consists of two crystalline solids that form a single new solid.

Monel was the brainchild of Robert Crooks Stanley of the International Nickel Company. Patented in 1906, it was named for the president of the company, Ambrose Monell. The second “L” was removed from the name of the metal because it was not possible to patent a person’s name at that time.


There are multiple variations of Monel alloys, starting with Monel 400, which contains at least 63% nickel, between 29% and 34% copper, between 2% and 2.5% iron, and between 1.5% and 2% manganese. Monel 405 adds no more than 0.5% silicon, and Monel K-500 adds between 2.3% and 3.15% aluminum and between 0.35% and 0.85% titanium. These and other variations all are valued for their resistance to attack by acids and alkalis, as well as for their high mechanical strength and good ductility.

Monel 400 contains the same quantity of nickel and copper as is found in a naturally occurring nickel ore in Ontario, Canada. It has high strength and can be hardened only by
cold working. Due to its resistance to deterioration, Monel 400 is most often used in parts found in marine and chemical environments.


Because of its resistance to acids, alkalis, seawater, and more, Monel 400 often is used in applications where corrosion might be a concern. According to, this includes marine environments where fixtures, valves, pumps, and piping systems are needed.

Other applications sometimes include chemical plants, including environments using sulfuric acid and hydrofluoric acid.

Standard Composition of Monel 400


Name Percentage
Nickel (plus cobalt) 63% minimum
Carbon 0.3% maximum
Manganese 2.0% maximum
Iron 2.5% maximum
Sulfur 0.024% maximum
Silicon 0.5% maximum
Copper 29-34%


Properties of Nickel-Copper Alloy Monel 400


Property Value (Metric) Value (Imperial)
Density 8.80*103 kg/m3 549 lb/ft3
Modulus of Elasticity 179 GPa 26,000 ksi
Thermal Expansion (20ºC) 13.9*10-6º C-1 7.7*10-6 in/(in*ºF)
Specific Heat Capacity 427 J/(kg*K) 0.102 BTU/(lb*ºF)
Thermal Conductivity 21.8 W/(m*K) 151 BTU*in/(hr*ft2*ºF)
Electric Resistivity 54.7*10-8 Ohm*m 54.7*10-6 Ohm*cm
Tensile Strength (Annealed) 550 MPa 79,800 psi
Yield Strength (Annealed) 240 MPa 34,800 psi
Elongation 48% 48%
Liquidus Temperature 1,350º C 2,460º F
Solidus Temperature 1,300º C 2,370º F

Alloy 400 Avaliability

Alloy 400 Specifications

Alloy 400 Tensile Requirements