ThePipingMart Blog Grades 405 Monel (UNS N04405) – Composition, Properties, and Uses

405 Monel (UNS N04405) – Composition, Properties, and Uses

Monel 405

UNS N04405 is a nickel-based alloy composed of copper and small amounts of iron and manganese. It is known for its excellent corrosion resistance, especially in acidic environments, and its high strength even at elevated temperatures. This makes it an ideal material for a variety of industrial applications, including valves, heat exchangers, pumps, and fasteners. Let’s explore the composition, properties, uses, and machining of Monel 405 in more detail.

405 Monel Composition

UNS N04405 contains approximately 64-68% nickel, with the remainder composed of copper (27-30%), iron (2%), manganese (1%), and other trace elements such as titanium and aluminium. This combination lends itself to some impressive mechanical properties that make it an attractive option for many industries. These include exceptional corrosion resistance in acidic environments with a pH of up to 4; good thermal conductivity; good formability; high strength; toughness; ductility; and weldability.

Ni Cu Fe S Mn C Si
63.0 min
2.5 max
2.0 max
.3 max
.5 max

405 Monel Chemical Properties

UNS N04405 is a nickel-copper alloy that features high corrosion resistance and mechanical strength. Its composition, with nickel making up 66–70 per cent and copper 27–33 per cent, makes it well suited for industrial settings where durability to both extreme temperatures and adverse environmental conditions is crucial. The additional alloying elements also help to increase strength and facilitate better formability. Monel 405 also has excellent welding properties, making it a reliable choice for projects which require welding. With its impressive chemical properties, Monel 405 stands out as an ideal solution for companies looking for a metal alloy with top performance in harsh environments.

405 Monel Mechanical Properties

Despite its relatively low strength compared to other metal alloys, UNS N04405 has several unique mechanical properties that make it well-suited for high-performing applications. It has a very low electrical conductivity, which is exceptional for a nickel-based alloy, and excellent corrosion resistance at both normal and elevated temperatures. Its excellent ductility means that it can be formed into complex shapes with ease, while its ability to withstand moderately-high temperatures makes it an ideal choice for heat exchangers and other equipment exposed to much greater heat than room temperature. Finally, Monel 405 exhibits very good weldability when handled correctly, making it suitable for joinery work in combination with other metals or components. Thus, while far from the strongest metal on the market, Monel 405 is an excellent addition to any manufacturing project where performance or resistance is paramount.

Condition Tensile (ksi) .2% Yield (ksi) Elongation % Hardness Brinell (3000 kg) Hardness Rockwell B
Cold-Drawn, As-Drawn

405 Monel Physical Properties

UNS N04405 is an exceptionally durable nickel-copper alloy known for its excellent corrosion-resistant properties. It is a nickel-iron-molybdenum alloy that is commonly used in marine applications due to its ability to stand up to seawater and other harsh environments. Monel 405 also has a high tensile strength meaning parts made with this alloy are strong and don’t wear or deform easily, even under temperature extremes. The combination of these beneficial physical traits makes it ideal for many mechanical parts, such as gears, shafts, and components used to resist cavitation erosion. All in all, Monel 405 provides the perfect blend of strength, formability and corrosion resistance for demanding applications.

Properties Metric Imperial
Density 8.80 g/cm³ 0.318 lb/in³
Melting point 1338°C 2440°F

405 Monel Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient (@ 20-100°C/68-212°F) 13.7 µm/m°C 7.61 µin/in°F
Thermal conductivity 21.8 W/mK 151 BTU in/hr.ft².°F

405 Monel Equivalent

  • AMS 4674
  • ASTM F467
  • ASTM F468
  • QQ N281

405 Monel Uses

Due to its combination of properties, UNS N04405 is used in a variety of industries. Its most common applications include valves, heat exchangers, pumps, fasteners, marine components such as propellers and rudders, turbine blades/diaphragms/shafts/mounts/risers/piping systems/condensers/manifolds/ducting systems/baffles/, aircraft parts like landing gear assemblies and exhaust stacks as well as chemical process equipment like tanks and columns. Its excellent resistance to saltwater corrosion makes it particularly popular for marine applications where exposure to seawater is unavoidable.


Machining Monel 405 can be difficult due to its hardening tendencies when heated, which can lead to premature tool wear if proper techniques aren’t used. The best way to machine this alloy is by using sharp tools with slow speeds combined with coolant lubrication or dry ice cooling methods where possible.


Welding can also be challenging depending on the specific application, but generally speaking, it does respond well to shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW) or flux cored arc welding (FCAW).

Corrosion Resistance

Monel 405 is a nickel-copper alloy that offers excellent corrosion resistance, even in conditions where other materials may not fare as well. Not only does Monel 405 resist corrosion from salt water and ocean spray, but it also resists deterioration from acids, neutral salts and organic acids, too. This makes it an ideal material for work in highly corrosive environments. The alloys are used in applications ranging from exploration vessels to water tanks and have proven to stand up to the rigours of such extreme conditions with ease. For those requiring reliable, durable protection against corrosion, Monel 405 is an OPTION worth considering.

Heat Resistance

Monel 405 is a type of nickel-copper alloy that is considered one of the most thermally resistant metals on the market. It has a remarkable degree of heat resistance, and at temperatures reaching as high as 1093 Celsius (2000 Fahrenheit), this alloy retains its structural solidity, even under extreme thermal stress. Monel 405 offers multiple benefits over other alloys, such as superior strength and superior corrosion resistance in many oxidizing environments, making it an ideal material for a variety of uses across numerous industries. Not only that but Monel 405 also costs less than some comparable alloys with less heat resistance. Overall, Monel 405 is an effective heat-resistant alloy that can be used in countless applications for industries around the world.

Heat Treatment

Monel 405 is a nickel-copper alloy that has excellent heat-treating properties, making it ideal for many industrial applications. Considered to be a low-temperature heat treatment alloy, it can be treated at temperatures as low as 425 degrees Celsius but still offers superior results when compared to conventional alloys. Monel 405 also provides strength gains throughout the entire temperature range and is highly resistant to stress cracking and corrosion. As such, it is a reliable and cost-effective solution for industries requiring strong metals capable of withstanding challenging environmental conditions. The heat treatment of Monel 405 can therefore provide significant benefits while helping businesses save money over time.


Monel 405 is an incredibly versatile nickel-based alloy that has a wide range of uses across many industries due to its excellent corrosion resistance in acidic environments combined with its remarkable strength even at elevated temperatures. It has become increasingly popular over the years thanks to its reliable performance as well as its ability to withstand harsh conditions without breaking down or corroding over time. Whether you need valves for a chemical plant or propellers for your boat – make sure you consider using Monel 405!                                                                                                                                                                                                                                     ​​

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