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Nickel Alloy Plate

Sandmeyer Steel Company stocks Monel® alloy 400 in the annealed condition in thicknesses from 3/16" (4.8mm) through 3" (76.2mm). Monel® alloy 400, in the annealed condition, exhibits moderate strength. This nickel alloy is also available in the as-rolled condition (Alloy 400AR) which imparts higher strength to the alloy. Alloy 400AR is stocked in thicknesses from .1875" through 3.00". Sandmeyer Steel Company is a supplier of Monel® nickel alloy 400.

Available thicknesses for Monel® Alloy 400:

3/16" 1/4" 3/8" 1/2" 5/8" 3/4" 1"
4.8mm 6.3mm 9.5mm 12.7mm 15.9mm 19mm 25.4mm
1 1/4" 1 1/2" 1 3/4" 2" 2 1/2" 3"
31.8mm 38.1mm 44.5mm 50.8mm 63.5mm 76.2mm

Monel® alloy 400 (UNS N04400) is a ductile nickel-copper alloy with resistance to a variety of corrosive conditions. The alloy is most frequently specified in environments ranging from mildly oxidizing through neutral and in moderately reducing conditions. An additional application area of the material is in marine environments and other nonoxidizing chloride solutions.

General Properties of Monel® Alloy 400

Monel® alloy 400 (UNS N04400) is a nickel-copper alloy with excellent resistance to a wide range of corrosive environments. It is resistant to chloride stress corrosion cracking and has high strength and toughness over a wide range of temperatures.

This nickel alloy is used extensively in many corrosive applications especially in the marine and chemical processing industries. Monel® nickel alloy 400 is readily fabricated by conventional processing operations.

Alloy 400AR is produced in the as-rolled condition to meet higher strength requirements


  • Chemical Processing Equipment – in fluorine, hydrofluoric acid, hydrogen fluoride, hydrochloric acid, sulfuric acid, neutral and alkaline salt solutions, caustic alkalies, non-oxidizing halides and dry chlorine service.
  • Marine Components – shipbuilding, valves, pumps, shafts and in sea and brackish water
  • Oil and Gas Production – splash-zones for offshore structures and sour gas applications
  • Ore Processing – uranium refining and separation in the production of nuclear fuels
  • Petroleum Refining – alkylation units, crude petroleum stills, piping and storage tanks
  • Power Generation – feed-water heaters and steam generators
  • Water Treatment – brine heaters and evaporators in seawater desalination plants


ASTM..................B 127
ASME..................SB 127
AMS ...................4544
Federal............... QQ-N-281

Chemical Analysis of Monel® Alloy 400

Weight % (all values are maximum unless a range is otherwise indicated)

Nickel (plus Cobalt) 63.0 min.-70.0 max. Iron 2.50
Copper 28.0 min.-34.0 max. Sulfur 0.024
Carbon 0.3 Silicon 0.5
Manganese 2.0

Physical Properties


0.318 lbs/in3
8.80 g/cm3

Specific Heat

0.102 BTU/lb-°F (68°F)
427 J/kg-°K (20°C)

Modulus of Elasticity

26.4 x 103 ksi (68°F)
182 GPa (20°C)


Thermal Conductivity 200°F (100°C)

150 BTU/hr/ft2/ft/°F (68°F)
22.0 W/m-°K (20°C)

Melting Range

2370 – 2460°F
1300 – 1350°C

Electrical Resistivity

307 Microhm-in at 70°C
0.511 Microhm-cm at 21°C

Mean Linear Expansion

Temperature Mean Linear Expansiona
°F °C in/in/°F x 10-6 um/m•°C
-320 -200
-300 -180 6.1 11.1
-200 -130 6.4 11.4
-100 -70 6.7 12.1
70 21
200 100 7.7 14.2
400 200 8.6 15.2
600 300 8.8 15.7
800 400 8.9 16.1
1000 500 9.1 16.3
1200 600 9.3 16.6
1400 700 9.6 17.0
1600 800 9.8 17.4
1800 900 10.0b 17.7
2000 1000 10.3b 18.1b

(a) annealed material, (b) extrapolated

Monel® Alloy 400 Mechanical Properties

Nominal Room-Temperature Mechanical Properties of Monel® Nickel Alloy 400 and 400AR

0.2% Offset
Tensile Strength Elongation, % Hardness
ksi MPa ksi MPa Brinell
Hot-Rolled, As-Rolled 40-75 276-517 75-95 517-655 45-30 125-215 70-96
Hot-Rolled, Annealed 28-50 193-345 70-85 482-586 50-35 110-140 60-76

Corrosion Resistance of Monel® Alloy 400

Monel® alloy 400 is a very versatile corrosion resistant material. It exhibits resistance to corrosion in many reducing environments, and it is generally more resistant than higher copper alloys to oxidizing media. Monel® alloy 400 is one of the few materials that will withstand contact with fluorine, hydrofluoric acid, hydrogen fluoride or their derivatives. The alloy has been found to offer exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point. Monel® Nickel alloy 400 also resists sulfuric and hydrochloric acids under reducing conditions. It has outstanding resistance to neutral and alkaline salts and has been utilized for many years as a material of construction for salt plants.

Monel® alloy 400 is one of the most widely used materials for marine applications, shipbuilding and seawater desalination plants. The alloy exhibits very low rates of corrosion in flowing sea or brackish water. However, under stagnant conditions, the nickel alloy can encounter crevice and pitting corrosion. Monel® alloy 400 resists stress corrosion cracking and pitting in most fresh and industrial water applications.

Effect of temperature on corrosion of Alloy 400 in sulfuric acid. Acid concentration, 5-6%. Velocity, 15.5-16.5 ft/min.

Plant corrosion tests in the storage of commercial 60-65% hydrofluoric acida

MATERIAL Corrosion Rate, mpy (mm/a)
Monel® Alloy 400 22 (0.56)
Nickel 200 >200 (>5.08)b
Inconel® Alloy 600 150 (3.81)
AISI 304 Stainless Steel >210 (>5.33)b
AISI 316 Stainless Steel >190 (>4.83)b
Mild Steel >170 (4.32)

(a) Acid contains 1.5-2.5% fluosilicic acid, 0.3-1.25% sulfuric acid, and 0.01-0.03% iron. Test specimens immersed in solution in storage tank. Temperature, 60-80°F (15-27°C); duration of test, 28 days.
(b) Specimen completely destroyed during test.

Effect of temperature on corrosion of Nickel 200 and Alloy 400 in 5% hydrocholoric acid.

Resistance of Nickel Alloys to Impingement Attack by Seawater at 150 ft/sec (45.7 m/s)

ALLOY Corrosion/Erosion Rate
mpy mm/a
Inconel® Alloy 625 Nil Nil
Incoloy ® Alloy 825 0.3 0.008
Alloy K-500 0.4 0.01
Monel® Alloy 400 0.4 0.001
Alloy 200 40 1.0

Fabrication Data for Monel® Alloy 400

Monel® alloy 400 is readily fabricated by conventional processing operations.

Hot Working

Monel® alloy 400 is a relatively soft material that is receptive to hot forming into almost any shape. The range of hot forming temperatures is 1200 - 2150°F (649 - 1177°C). For heavy reductions the recommended temperature range is 1700 – 2150°F (927 – 1177°C). Light reductions are possible with temperatures as low as 1200°F (649°C). Working at lower temperatures will result in higher mechanical properties and smaller grain size.

Cold Working

Monel® alloy 400 is readily cold worked by virtually all cold fabrication methods. Cold working should be performed on annealed material. The alloy has a somewhat higher work hardening rate than carbon steel, but not as high as 304 stainless steel.


Monel® alloy 400 can be machined at standard rates with conventional machine tools. Surface cutting speeds should be low compared to those used for carbon steel due to the alloy’s high work-hardening rate.


Monel® alloy 400 can be welded to itself or dissimilar metals by utilizing conventional welding processes. These include conventional or hot wire GTAW (TIG), plasma arc, GMAW (MIG/MAG) and SMAW (MMA). The choice of welding product is dependent upon the materials being welded and the environment in which it occurs.

NOTE: The information and data in this product data sheet are accurate to the best of our knowledge and belief, but are intended for informational purposes only, and may be revised at any time without notice. Applications suggested for the materials are described only to help readers make their own evaluations and decisions, and are neither guarantees nor to be construed as express or implied warranties of suitability for these or other applications. Stainless Steel, Nickel Alloy and Titanium products are classified as sheet if the thickness of the metals is less than 3/16” (4.7mm). If the thickness of the metal is 3/16” (4.7mm) or more, then it is considered a plate.

Trademark Notices

Inconel®, Incoloy®, and Monel® are registered trademarks of Special Metals Corporation.