Monel 400

Monel 400

N04400 | 2.4360 | NICU30FE | NA 13 | МНЖМЦ 28-2,5-1,5 | NW 4400 | NU-30M

Monels are nickel-copper alloys with small amounts of iron and other alloying elements. They are considered to be stronger than pure nickel and provide exceptional resistance to wide range of environments and chemical agents, including marine environment.

Monel 400 is a solid strengthened solution alloy, with its major alloying elements in solid phase in the microstructure. It is a binary alloy with a face-centered cubic lattice structure. Its toughness and mechanical properties are retained from cryogenic temperatures at about 480°C. The grade does not undergo ductile to brittle transition even in the cryogenic range.

The impact strength at 24°C is 220 ft. lbs while at -190°C the strength remains 196 ft. lbs. Hence, no evidence of transition or fracture. The strength, as well as hardness, is retained with a very little loss of ductility and impact properties. If creep and rupture properties up to 540°C, are attained under high oxidizing condition the grade can be useful in several other applications. Monel 400 has better resistance to oxidizing than higher alloys of copper. Hence, the alloy can be suitably serviced under variable environments. The fatigue strength of hot-rolled specimen of the alloy is obtained at 290 MPa in 10^8 cycles (rotating beam test).

Hence, the alloy can be conveniently used in dynamic applications. The shear strength of the alloy in hot rolled condition remains around 340 MPa. The grade is normally magnetic at room temperature and hence it can be used in relative applications. Its magnetic properties might change after cold working or welding. Annealed alloy has lower strength and needs to be appropriately tempered for better strength. Cold working is used to enhance the hardening of the alloy. The grade is specifically used for its toughness in impact as well as torsion. The hot rolled specimen of the alloy absorbs 120 ft. lbs in Izod test, and 220 ft. lbs in Charpy v-notch test.

The alloy being softer than most of the grades, hot forming is very convenient and almost every required shape is obtained. The alloy can be readily formed, fabricated and machined. With the appropriate amount of hot work and cold work, and required heat treatment, the alloy can successfully deliver the required mechanical properties as per the needed applications. Pickling is often done on the alloy to obtain clean and better surface.

  • Chemical properties
  • Physical properties
  • General data
  • Standards Specifications
  • Forms of Supply
  • Corrosion Resistance
  • Heat Treatment
  • Weldability
  • Machining
  • Applications
  • Possible grade alternatives
Grade   Ni C Mn Cu Si Fe S
Monel 400 Min. 17.5 - - 28.00 - - -
Max. 18.5 0.30 2.00 34.00 0.08 2.50 0.024
Density 8.80 g/cm 3 / 0.318 lb/in 3
Melting Point 1300 -1350 (°C) / 2370 – 2460 (°F)
Specific Heat @ 70°F 0.102 Btu/lb/°F
Thermal Conductivity @ 70°F 151 Btu•in/h/ft2/°F
Elastic Modulus @ 70ºF (tension) 26.0 x 106 psi
Electrical Resistivity @ 70°F 0.511 μΩ•m
Annealed 900 – 928 (°C) / 1650 – 1700 (°F)
Quench Rapid Air/Water
Poisson’s Ratio 0.32
Standard 400
UNS N04400
EN NiCu30Fe
BS NA 13
GOST МНЖМц 28-2,5-1,5
JIS NW 4400
Pipes & Tubes
Summary Standards
Standard Specification for Nickel Seamless Pipe and Tube ASTM B161
Standard Specification for Seamless Nickel and Nickel Alloy Condenser and Heat-Exchanger Tubes ASTM B163
Standard Specification for Electric Fusion Welded Nickel and Nickel Alloy Pipe ASTM B474
Standard Specification for Welded Nickel (UNS N02200/UNS N02201) and Nickel Copper Alloy (UNS N04400) Pipe ASTM B725
Standard Specification for Welded Nickel (UNS N02200/UNS N02201) and Nickel Copper Alloy (UNS N04400) Tube ASTM B730
Fittings & Flanges
Summary Standards
Standard Specification for Factory-Made Wrought Nickel and Nickel Alloy Fittings ASTM B366
Standard Specification for Nickel Alloy Forgings ASTM B564

Piping and tubing, fittings and flanges, washers.

The alloy has brilliant properties in general corrosion resistance to aggressive media in a wide range of temperatures. Its resistance to seawater as well as steam widens its range of applications including marine components, steam power plants, etc. The alloy finds its extensive use in environments that include caustic solutions, alkalis, non-oxidizing mineral acids.

Chemicals such hydrofluoric acids, hydrochloric and sulphuric acids can be suitably resisted. However, oxidizing salts should be avoided because it would increase the corrosion rate of the alloy. Great resistance to chloride stress corrosion cracking is also one of its many benefits. However, the solutions need to be de-aerated since aeration would accelerate the corrosion rate of the alloy. Due to the presence of copper, the alloy may be prone to attacks by nitric acid and ammonia. Nitric acid dissolves copper by oxidizing it whilst ammonia in the presence of moisture forms - copper ammonia complex can be unsuitable for the compound.

Annealing on the alloy can significantly soften the work-hardened alloy with the time at a temperature depending on the previous work done. Open annealing can be done at 870-980°C for about 10 mins while box annealing can be done at 760-820°C for about 2-3 hours. The grain refinement that occurs following the process can be used in further applications.

The choice of welding materials need to be done based upon the environment it is exposed. Normal welding techniques like gas tungsten arc welding, shielded metal arc welding, gas metal arc welding, and submerged arc welding can be used. Inconel metals are normally used as filler metals. Neither pre-heat nor post- heat is required. The alloy's high purity and thermal conductivity make the weld penetration low.

The alloy can be satisfactorily machined at proper rates by controlling the tool design, speed, and coolants. There might be work hardening during machining of the alloy. Rigid tooling and powerful machinery can be required in some cases.

Aerospace applications, Feed water and steam generator tubing, Pickling bat heating coils, Crude oil distillation towers, Chemical plant equipment, Chlorinated solvents, Industrial heat exchangers, Frames for eyeglasses, Marine fixtures, pumps, valves and piping systems for sea water applications, Brine heaters, sea water scrubbers in tanker inert gas systems, Musical instruments, Transfer piping from oil refinery crude columns, De-aerating heaters, Boiler feed water heaters and other heat exchangers, Chemical and hydrocarbon processing equipment, Sulfuric acid and hydrofluoric acid alkylation plants, Cladding for the upper areas of oil refinery crude columns, Propeller and pump shafts, chlorinated plastics.

Inconel 316L
Grade   Ni C Mn Si P Cr Mo S

Inconel 316L

Min. 10.0 - - - - 16.0 2.0 -
Max. 14.0 0.035 2.00 1.00 0.045 18.0 3.0 0.30

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