Corrosion Resistant Alloys

NAS NW400 (UNS N04400), comparable to Monel® 400 Alloy

An alloy including copper and nickel, NAS NW400 (NW 4400, UNS N04400), comparable to Monel® 400 Alloy, shares in the noble properties of copper and passivation of nickel to provide excellent corrosion resistance. It is therefore used in seawater desalination systems, heat exchangers and marine structure jackets. Nippon Yakin supplies this product in plate, sheet and strip forms.

  • Image: Coil
    Coil
  • Image: Sheet
    Sheet
  • Image: Plate
    Plate

Designation / Standard

Nippon Yakin Grade ASTM B127 EN JIS H4551
NAS NW400 UNS N04400 NW 4400

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Chemical Composition

NW 4400

  C Si Mn S Ni Cu Fe
Min 63.0 28.0
Max 0.30 0.5 2.0 0.025 34.0 2.5

UNS N04400

  C Si Mn S Ni Cu Fe
Min 63.0 28.0
Max 0.3 0.5 2.0 0.024 34.0 2.5

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Physical Properties

Specific heat (J/kg・K) 20℃ 427
Specific resistivity (μΩ・cm) 54.7
Thermal conductivity (W/m・K) 21.8
Coefficient of thermal expansion (10-6/℃) 20–100℃ 13.9
Melting point (℃) 1300-1350

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Mechanical Properties

Mechanical Properties at Room Temperature

NW 4400 Annealing

0.2% proof stress
(N/mm2)
Tensile strength
(N/mm2)
Elongation
(%)
Hardness
(HV)
≥ 195 ≥ 480 ≥ 35

UNS N04400 Annealing Hot-rolled plate

0.2% proof stress
(N/mm2)
Tensile strength
(N/mm2)
Elongation
(%)
Hardness
(HV)
≥ 195 ≥ 485 ≥ 35

UNS N04400 Annealing Cold-rolled sheet

0.2% proof stress
(N/mm2)
Tensile strength
(N/mm2)
Elongation
(%)
Hardness
(HV)
≥ 195 485-585 ≥ 35

Examples Annealing Hot-rolled plate

  0.2% proof stress
(N/mm2)
Tensile strength
(N/mm2)
Elongation
(%)
Hardness
(HV)
12-mm thick 209 513 52 131

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Work Hardening Properties

NAS NW400 is far less hard than SUS 301 and SUS 304, making bending and other such processes easy to perform.

Image: Work Hardening Properties

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Corrosion Resistance

Type of acid Test temperature (℃) Concentration (wt%) Corrosion rate (mm/y)
NAS NW400
(UNS N04400)
SUS 316L
(UNS S31603)
Sulfuric acid 80 5 0.28 1.67
10 0.27 4.69
20 0.20 71.9
40 0.16 765
60 0.14 704
80 0.80 33.7
Boiling 5 0.21 8.19
10 0.36 24.6
20 0.53 179
40 2.12 3129
Hydrochloric acid 80 0.1 0.34 0.02
1 0.40 2.73
2 0.46 6.75
3 0.63 14.9
Boiling 0.1 0.13 0.01
1 1.37 8.86
2 3.06 27.5
3 3.45 76.6
Fluoric acid 80 0.1 0.28 0.50
1 0.32 14.5
2 0.37 35.4
3 0.35 54.1
Nitric acid Boiling 20 4615 0.02
40 >10000 0.05
60 >10000 0.17
Phosphoric acid Boiling 20 0.24 0.04
40 0.16 0.25
60 0.24 0.56
80 6.90 25.0
Formic acid Boiling 20 0.05 0.35
40 0.08 0.62
60 0.05 0.73
80 0.02 0.49
Acetic acid Boiling 20 0.11 <0.01
40 0.04 <0.01
60 0.04 <0.01
80 0.05 <0.01
99.7 0.01 <0.01

24-hour immersion test

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Weldability

TIG, MIG, shield metal arc and resistance welding can all be used with NAS NW400. For the TIG and MIG consumable, we recommend YNiCu-7.

Heat Treatment

Heat treatment should be carried out between 700 and 900℃, preferably followed by rapid air cooling.

Applications

Marine structure covering; desalination, salt production and oil refining equipment; ship parts; heat exchangers; valves and pump members for chemical and seawater desalination plants.

* Monel is a registered trademark of Special Metals Corporation.

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