UNS Number N04400

Monel 400 is a nickel-copper alloy that is resistant to sea water and steam at high temperatures as well as to salt and caustic solutions. Alloy 400 is a solid solution alloy that can only be hardened by cold working. This nickel alloy exhibits characteristics like good corrosion resistance, good weldability and high strength. A low corrosion rate in rapidly flowing brackish or seawater combined with excellent resistance to stress-corrosion cracking in most freshwaters, and its resistance to a variety of corrosive conditions led to its wide use in marine applications and other non-oxidizing chloride solutions. This nickel alloy is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. As would be expected from its high copper content, alloy 400 is rapidly attacked by nitric acid and ammonia systems.

 

Available Forms of Monel 400 at Rooplaxmi Steels:

•           Bar
•           Sheet
•           Plate
•           Pipe & Tube (welded and seamless)
•           Pipe Fittings
•           Wire

 

Characteristics of Monel 400:

 

•           Resistant to seawater and steam at high temperatures
•           Excellent resistance to rapidly flowing brackish water or seawater
•           Excellent resistance to stress corrosion cracking in most freshwaters
•           Particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated
•           Offers some resistance to hydrochloric and sulfuric acids at modest temperatures and concentrations, but is seldom the material of choice for these acids
•           Excellent resistance to neutral and alkaline salt
•           Resistance to chloride induced stress corrosion cracking
•           Good mechanical properties from sub-zero temperatures up to 1020° F
•           High resistance to alkalis

 

Monel 400 Chemical Composition, %:

Ni	Cu	Fe	C	Mn	Si
63.0 min	28.0-34.0	2.5 max	0.3 max	2.00 max	0.5 max

 

Application of Monel 400:

•           Marine engineering
•           Chemical and hydrocarbon processing equipment
•           Gasoline and freshwater tanks
•           Crude petroleum stills
•           De-aerating heaters
•           Boiler feed water heaters and other heat exchangers
•           Valves, pumps, shafts, fittings, and fasteners
•           Industrial heat exchangers
•           Chlorinated solvents
•           Crude oil distillation towers

 

Machining and Fabrication with Monel 400:

Monel 400 can easily be welded by gas-tungsten arc, gas metal arc or shielded metal arc processes using appropriate filler metals. There is no need for post weld heat treatment, however, thorough cleaning after welding is critical for optimum corrosion resistance, otherwise there is the risk of contamination and embrittlement.
Finished fabrications can be produced to a wide range of mechanical properties when proper control of the amount of hot or cold working and the selection of appropriate thermal treatments is done.
Like most other nickel alloys, Monel 400 is typically tough to machine and will work harden. However, excellent results can e obtained if you make the correct choices for tooling and machining.

 

Monel 400 ASTM Specification:

Pipe Smls	Pipe Welded	Tube Smls	Sheet / Plate	Bar	Forging	Fitting
B165	B725	B163	B127	B164	B564	B366

Welding Wire Designations:
AWS A5.14 – ERNiCu7 (Monel Ti)

 

Mechanical Properties of Monel 400:

Typical room temperature Tensile Properties of Annealed Material

Product form	Condition	Tensile (ksi)	0.2 % Yield (ksi)	Elongation (%)
Rod & Bar	Annealed	75-90	25-50	60-35
Rod & Bar	Cold Drawn Stress Relieved	84-120	55-100	40-22
Plate	Annealed	70-85	28-50	50-35
Sheet	Annealed	70-85	30-45	45-35
Tube & Pipe Smls	Annealed	70-85	25-45	50-35