Ni-Cu 400 (Monel®) (UNS N04400)


Alloy 400 (Monel®) is a ductile nickel-copper alloy with resistance to a variety of corrosive conditions. The alloy is most frequently applied in a range of environments ranging from mildly oxidizing through neutral and to moderately reducing conditions. An additional application area of the material is in marine environments and other non-oxidizing chloride solutions.

The alloy has a long history of use as a corrosion resistant material, dating back to the early twentieth century when it was developed as an attempt to use a high copper content nickel ore. The nickel and copper contents of the ore were in the approximate ratio which is now formally specified for the alloy.

As with commercially pure nickel, Alloy 400 is low in strength in the annealed condition. For this reason, a variety of tempers are used which have the effect of increasing the strength level of the material.

Chemical Composition

Chemical Composition (wt%) limits as specified in ASTM B164*

Carbon 0.3 Manganese 2.0
Nickel 63.0 min Silicon 0.5
Copper 28.0-34.0 Sulfur 0.03
Iron 2.5    

*Maximum, unless range is indicated

Physical Properties

Physical properties for Alloy 400

Density, lb/in3 0.319
Modulus of Elasticity, psi 26 x 106
Coefficient of Thermal Expansion, 68-212˚F, /˚F 7.7 x 10-6
Thermal Conductivity, Btu/ft hr ˚F 14
Specific Heat, Btu/lb ˚F 0.10
Electrical Resistivity, Microhm-in 20.0

Mechanical Properties

Mechanical property requirements as specified for annealed product in ASTM B 164

Yield Strength, min. (ksi) 25
Tensile Strength, min. (ksi) 70
Elongation, min. (%) 35


Typical standards for Alloy 400