Monel 400 is a Nickel-Copper alloy, resistant to sea water and steam at high temperatures as well as to salt and caustic solutions.
Monel 400 is a nickel-copper alloy with excellent corrosion resistance in a wide variety of media. Monel 400 is characterized by good general corrosion resistance, good weldability and moderate to high strength. The alloy has been used in a variety of applications. It has excellent resistance to rapidly flowing brackish water or seawater. It is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. The alloy is slightly magnetic at room temperature. Monel 400 is widely used in the chemical, oil and marine industries.
Characteristics
Corrosion resistance in an extensive range of marine and chemical environments. From pure water to nonoxidizing mineral acids, salts and alkalis.
This alloy is more resistant to nickel under reducing conditions and more resistant than copper under oxidizing conditions, it does show however better resistance to reducing media than oxidizing.
Good mechanical properties from subzero temperatures up to about 480C.
Good resistance to sulfuric and hydrofluoric acids. Aeration however will result in increased corrosion rates. May be used to handle hydrochloric acid, but the presence of oxidizing salts will greatly accelerate corrosive attack.
Resistance to neutral, alkaline and acid salts is shown, but poor resistance is found with oxidizing acid salts such as ferric chloride.
Excellent resistance to chloride ion stress corrosion cracking.
Applications
Feed water and steam generator tubing.
Brine heaters, sea water scrubbers in tanker inert gas systems.
Sulfuric acid and hydrofluoric acid alkylation plants.
Pickling bat heating coils.
Heat exchangers in a variety of industries.
Transfer piping from oil refinery crude columns.
Plant for the refining of uranium and isotope separation in the production of nuclear fuel.
Pumps and valves used in the manufacture of perchlorethylene, chlorinated plastics.
Monoethanolamine (MEA) reboiling tube.
Cladding for the upper areas of oil refinery crude columns.
Propeller and pump shafts.
MONEL nickel-copper alloy 400 (UNS N04400/W.Nr. 2.4360 and 2.4361) is a solid-solution alloy that can be hardened only by cold working. It has high strength and toughness over a wide temperature range and excellent resistance to many corrosive environments. Composition is shown in Table 1.
Alloy 400 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 feedwater heaters and other heat exchangers; and deaerating heaters.
Table 1 - Limiting Chemical Composition, %, of MONEL Alloy 400
Nickel (plus Cobalt) .....................................................63.0 min.
Carbon..........................................................................0.3 max.
Manganese ...................................................................2.0 max.
Iron................................................................................2.5 max.
Sulfur ........................................................................0.024 max.
Silicon ...........................................................................0.5 max.
Copper ......................................................................28.0 - 34.0
Table 2 - Physical Constants of MONEL Alloy 400a
Density, g/cm3 .....................................................................8.80
lb/in.3 ...................................................................0.318
Melting Range, °F .....................................................2370-2460
°C .....................................................1300-1350
Modulus of Elasticity, 103 ksi
Tension .............................................................................26.0
Compression ....................................................................26.0
Torsion................................................................................9.5
Poisson’s Ratio....................................................................0.32
Curie Temperature, °F .....................................................70-120
°C ......................................................21-49