Nickel Alloy 400

Material

Products Description

Alloy 400, also known as UNS N04400 or Monel 400, is a ductile nickel-copper alloy that offers excellent resistance to various corrosive conditions. It is commonly used in environments that range from mildly oxidizing to neutral, as well as moderately reducing conditions.One of the notable features of Alloy 400 is its resistance to corrosion by a wide range of substances, including seawater, steam, salt, and caustic solutions. This makes it particularly well-suited for applications in marine environments and other nonoxidizing chloride solutions.The alloy exhibits good mechanical properties over a wide temperature range and is often used in applications such as chemical processing, marine engineering, hydrocarbon and petrochemical processing, and equipment for the production of gasoline, freshwater, and steam.It's worth noting that Alloy 400 has a relatively low corrosion rate in flowing seawater but can be susceptible to stress corrosion cracking in certain conditions. Therefore, it is essential to consider the specific operating conditions and consult the alloy's manufacturer or a materials engineer for guidance on its suitability for a particular application.

Applications

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

Standards

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

General Properties

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.
The alloy is used extensively in many corrosive applications especially in the marine and chemical processing industries. Alloy 400 is readily fabricated by conventional processing operations.
Alloy 400AR is produced in the as-rolled condition to meet higher strength requirements

Chemical Analysis

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

Density

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

Mechanical Properties

Nominal Room-Temperature Mechanical Properties of Alloy 400 and 400AR

FORM AND CONDITION	Yield Strength 0.2% Offset		Tensile Strength		Elongation, %	Hardness
FORM AND CONDITION	ksi	MPa	ksi	MPa	Elongation, %	Brinell (3000-kg)	Rockwell B
Plate
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

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

MATERIAL	Corrosion Rate, mpy (mm/a)
Alloy 400	22 (0.56)
Nickel 200	>200 (>5.08)b
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.

Nickel Alloy 400/400AR

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

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

Fabrication Data

Alloy 400 is readily fabricated by conventional processing operations.
Hot Working
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

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.

Machining

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.

Welding

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.