Womic Stainless Steel Co., Ltd

Monel 400 Superalloy Steel Tubes

high-temperature alloy pipe,Stainless Steel Bolts,UNS N04400 Nickel Alloy Tubes
1
2
3

Monel 400 Superalloy Steel Tubes

High-Performance Seamless and Welded Tubes for Marine Engineering, Hydrofluoric Acid Service, and Extreme Corrosive Environments

Premium Monel 400 Superalloy Steel Tubes for Seawater Cooling Systems, HF Alkylation Units, Chemical Processing, and High-Velocity Brine Service

Womic Steel manufactures premium Monel 400 Superalloy Steel Tubes, including Seamless and Welded options. Our nickel-copper alloy superalloy tubes provide exceptional resistance to seawater corrosion, outstanding resistance to hydrofluoric acid (HF), excellent resistance to stress corrosion cracking in chloride environments, and superior erosion resistance at high velocities. With a unique combination of high nickel (≥63%) and copper (28-34%), Monel 400 tubes offer outstanding performance in marine engineering, seawater cooling, hydrofluoric acid processing, alkylation units, brine service, and chemical processing where other materials suffer from localized corrosion or erosion. They are the ideal choice for seawater cooling systems, HF alkylation heat exchangers, chemical injection lines, propeller shafts, pump components, and extreme corrosive service where conventional materials fail under high-velocity seawater or hydrofluoric acid attack.

    Welcome to leave us a message

  • Close

Key Features of Monel 400 Superalloy Steel Tubes

Exceptional Seawater Corrosion Resistance: Monel 400 has outstanding resistance to seawater corrosion, particularly at high velocities where copper alloys and stainless steels fail due to erosion or impingement attack. It is immune to stress corrosion cracking in seawater.

Superior Resistance to Hydrofluoric Acid (HF): Monel 400 is the premier material for handling hydrofluoric acid (HF) across a wide range of concentrations and temperatures, making it the standard material for HF alkylation heat exchangers in refineries.

Excellent Erosion and Impingement Resistance: Monel 400 has outstanding resistance to erosion and impingement attack in high-velocity seawater and brine service (up to 10 m/s or 33 ft/s), significantly outperforming copper-nickel alloys and stainless steels.

Excellent Chloride Stress Corrosion Cracking Resistance: High nickel content (≥63%) provides outstanding resistance to chloride-induced SCC, outperforming all austenitic stainless steel grades.

Good Resistance to Reducing Acids: Excellent performance in deaerated sulfuric acid, hydrochloric acid, phosphoric acid, and organic acids, particularly in the absence of oxidizing agents.

Good High-Temperature Strength: Maintains excellent mechanical properties up to 400°C (752°F) in non-oxidizing environments.

Excellent Resistance to Biofouling: Monel 400 resists marine biofouling, reducing maintenance requirements and maintaining flow efficiency.

Surface Quality: Smooth internal and external surfaces available in annealed, pickled, or polished conditions for critical marine and chemical applications.

Good Weldability: Nickel-copper alloy offers good weldability with matching filler metals (ERNiCu-7). Weld zones retain corrosion resistance comparable to the base metal.

Good Fabricability: Excellent formability and ductility for bending, coiling, and swaging operations.

International Certification: Tubes can be certified by ABS, BV, DNV, LR, GL, RINA, CCS, KR, and NK, and comply with NACE MR0175/ISO 15156 (limited sour service), ASME Boiler & Pressure Vessel Code, and NORSOK M-650 standards.

Monel 400 Superalloy Steel Tube Related International Standards and Grades

The Monel 400 Superalloy Steel Tubes produced by Womic Steel conform to multiple international specifications used in marine, chemical, and pressure applications:

Standard

Description

Equivalent Grade / Material Number

ASTM B163 / ASME SB163

Seamless nickel and nickel alloy condenser and heat exchanger tubes

UNS N04400 (Monel 400)

ASTM B165 / ASME SB165

Seamless nickel-copper alloy pipe and tube

UNS N04400

ASTM B725

Welded nickel-copper alloy tube

UNS N04400

ASTM B127

Nickel-copper alloy plate, sheet, and strip

UNS N04400

NACE MR0175 / ISO 15156

Sour service compliance (limited conditions)

Monel 400

EN 10216-5

Seamless stainless steel tubes for pressure purposes

2.4360 (NiCu30Fe)

DIN 17751

Nickel alloy tubes

NiCu30Fe

ISO 6207

Nickel alloy seamless tubes

NiCu30Fe

NORSOK M-650

Qualification of special materials

Monel 400

These standards ensure that Monel 400 Superalloy Steel Tubes meet global requirements for chemical composition, mechanical performance, testing, and dimensional accuracy.

Commonly Used Superalloy Steel Tube Grades & Standards Produced by Womic Steel

Different specifications can be customized according to special requirements.

Execution Standard

Main Standard

Standard Grade

ASTM (USA)

ASTM B163, B165, B725, B622, B444

Monel 400 (N04400), Monel K-500 (N05500), Inconel 600 (N06600), Inconel 625 (N06625), Hastelloy C276 (N10276)

ASME (USA)

SB163, SB165, SB622, SB444

Monel 400, Monel K-500, Inconel 600, Inconel 625, Hastelloy C276

EN / DIN (Europe)

EN 10216-5, EN 10217-7

2.4360 (Monel 400), 2.4375 (Monel K-500), 2.4816 (Inconel 600), 2.4856 (Inconel 625)

ISO (International)

ISO 6207

NiCu30Fe (2.4360), NiCr22Mo9Nb (2.4856)

NORSOK (Norway)

NORSOK M-650

Monel 400, Inconel 625

Chemical Composition of Monel 400 Superalloy Steel Tube (UNS N04400)

Element

Ni

Cu

Fe

C

Mn

P

S

Si

Others

Monel 400

≥63.0

28.0–34.0

≤2.5

≤0.30

≤2.0

≤0.024

≤0.024

≤0.50

Note: Monel 400 (UNS N04400) is a nickel-copper alloy with high nickel (≥63%) and copper (28-34%) content. The high nickel content provides excellent resistance to chloride stress corrosion cracking, while the copper content provides outstanding resistance to hydrofluoric acid and seawater biofouling. Unlike Inconel alloys, Monel 400 is a solid solution strengthened alloy with no intentional precipitation hardening additions, making it exceptionally stable in marine environments.


Comparison with Other Marine and Chemical Alloys:

Property

Monel 400

CuNi 90/10

316L Stainless

Super Duplex 2507

Titanium Grade 2

Nickel (%)

≥63

10

10-14

6-8

Copper (%)

28-34

90

Seawater Erosion Resistance

Excellent

Poor

Good

Excellent

Excellent

HF Acid Resistance

Excellent

Poor

Poor

Poor

Poor

Max Seawater Velocity (m/s)

10

3

5

10

20

Chloride SCC Resistance

Excellent

Poor

Poor

Excellent

Excellent

Biofouling Resistance

Good

Poor

Fair

Fair

Excellent


Comparison with Other Nickel Alloys:

Property

Monel 400

Inconel 600

Inconel 625

Alloy 825

Nickel (%)

≥63

≥72

≥58

38-46

Copper (%)

28-34

1.5-3.0

HF Acid Resistance

Excellent

Poor

Poor

Poor

Seawater Erosion Resistance

Excellent

Good

Excellent

Good

High-Temperature Strength

Good

Excellent

Excellent

Good

Cost

Medium-High

High

Premium

Very High

Monel 400 Superalloy Steel Tube Mechanical Properties and Heat Treatment Requirements

The Monel 400 Superalloy Steel Tube offers excellent mechanical properties and good fabricability for demanding marine and chemical applications.

Property

Unit

Monel 400 (Annealed)

Tensile Strength (min)

MPa

≥480

Yield Strength (0.2% offset, min)

MPa

≥170

Elongation (min)

%

≥35

Hardness (typical)

HRB

≤80

Density

g/cm³

8.80

Melting Range

°C

1300–1350

Thermal Conductivity (20°C)

W/m·K

21.8

Coefficient of Thermal Expansion (20–100°C)

μm/m·K

13.9

Modulus of Elasticity (20°C)

GPa

179


High-Temperature Tensile Properties (Typical Values) :

Temperature (°C)

Tensile Strength (MPa)

Yield Strength (MPa)

20

500–600

200–280

100

480–580

180–260

200

460–560

170–250

300

440–540

160–240

400

420–500

150–220

500

380–460

130–200


Maximum Recommended Service Temperatures:

Service Type

Maximum Temperature

Continuous Service (Seawater/Brine)

260°C (500°F)

Continuous Service (HF Acid)

150°C (302°F)

Continuous Service (Reducing Environment)

400°C (752°F)

Intermittent Service

450°C (842°F)

Sour Service (NACE MR0175)

232°C (450°F) – limited

Minimum Service Temperature

-196°C (-321°F)

Critical Note: Monel 400 is not recommended for service in oxidizing acids (e.g., nitric acid) as it will experience rapid attack. It should also not be used in sulfur-containing environments at high temperatures due to susceptibility to sulfur attack. For applications requiring high strength, Monel K-500 (precipitation-hardenable version) should be considered.


Monel 400 Superalloy Steel Tube – Heat Treatment Condition:

Monel 400 tubes are normally supplied in the annealed condition (heat treated at 700–800°C) followed by air cooling. This heat treatment:

l  Relieves internal stresses from cold drawing or cold pilgering

l  Restores optimum ductility and corrosion resistance.

l  Ensures a stable microstructure for service.


Monel 400 Superalloy Steel Tube – Delivery Condition:

Tubes are normally supplied in annealed and pickled condition, providing a clean, smooth surface and excellent corrosion resistance. Upon request, bright annealed (BA) finish can be provided for applications requiring ultra-clean internal surfaces. Cold worked finishes are also available for higher strength requirements.

Manufacturing Process of Monel 400 Superalloy Steel Tube (Seamless)

Womic Steel adopts advanced production technology to ensure each Monel 400 Superalloy Steel Tube meets exact specifications and flawless surface quality.

Raw Material Selection: High-quality Monel 400 billets from certified premium mills (Special Metals, VDM Metals) with certified chemical composition (Ni ≥63%, Cu 28-34% verification) and traceability.

Heating and Piercing: Billets heated to a controlled temperature range (1100–1200°C) and pierced using a rotary piercing mill to form hollow shells.

Hot Rolling: Shells elongated and rolled to desired intermediate size with strict temperature control.

Cold Drawing / Cold Pilgering: Tubes refined to precise dimensions and improved surface finish. Multiple passes with intermediate annealing required due to work hardening.

Annealing: Heat treatment at 700–800°C to relieve stresses and restore ductility. Performed in controlled atmosphere furnaces for bright annealed finish.

Pickling & Passivation: Removal of oxides using specialized pickling acids optimized for nickel-copper alloys; thorough rinsing required.

Straightening and Dimensional Calibration: Ensures consistent roundness and wall uniformity.

Final Inspection & Marking: Each tube tested, marked with grade, heat number, standard, and tube dimensions before packing.

This process guarantees a smooth internal bore, high structural integrity, and exceptional corrosion resistance across all batches of Womic Steel’s Monel 400 Superalloy Steel Tubes.

Manufacturing Process of Monel 400 Superalloy Steel Tube (Welded)

Womic Steel utilizes state-of-the-art manufacturing technology to ensure every Monel 400 Welded Superalloy Steel Tube meets precise specifications and delivers excellent surface quality and performance.

Raw Material Selection: High-quality Monel 400 strips/coils from certified premium mills with full traceability.

Slitting & Uncoiling: The steel coil is slit to the required width and uncoiled for feeding into the forming mill.

Forming & Welding: The strip is progressively formed into a cylindrical shape and the edges are welded together using advanced TIG or Plasma welding techniques with matching filler metal (ERNiCu-7) to create a solid weld seam.

Weld Seam Treatment: The external weld bead is removed to achieve a smooth surface, and the internal bead may be controlled or treated for bore cleanliness.

Annealing: A full heat treatment process at 700–800°C is applied to relieve stresses from welding and forming.

Sizing & Calibration: The tube is passed through a sizing mill to achieve the final precise outer diameter and roundness.

Straightening: The tube is straightened to ensure optimal linearity.

Pickling & Passivation: Chemical treatment removes scale and impurities, while promoting the formation of a protective passive oxide layer on the surface, including the weld zone.

Non-Destructive Testing (NDT) : The weld seam is inspected using methods like Eddy Current or Ultrasonic Testing to ensure integrity and quality.

Final Inspection & Marking: Each tube undergoes dimensional checks, visual inspection, and is marked with grade, heat number, and relevant standards before packaging.

This controlled process guarantees a consistent weld seam, excellent dimensional accuracy, and superior corrosion resistance for every batch of Womic Steel’s Monel 400 Welded Superalloy Steel Tubes.

Monel 400 Superalloy Steel Tube Dimensions and Tolerances

Outside Diameter: 3.2mm – 152mm (1/8″ – 6″)

Wall Thickness: 0.5mm – 12.7mm (0.020″ – 0.500″)

Length: Up to 20m (straight lengths); coiled tubing up to 500m available

OD Tolerances:

Standard: ±0.08mm

Precision: ±0.05mm (upon request)

Wall Thickness Tolerances:

Standard: ±10% of nominal

Precision: ±8% of nominal (upon request)

Straightness: 0.5mm per 1000mm length typical


ANSI B 36.19/ANSI B36.10 DIMENSIONS OF SEAMLESS &WELDED STAINLESS STEEL PIPE

Nominalsize

mm

ANSIB36.19

ANSIB36.10ANSIB36.10

DN

NPS

mm

5S

10S

40S

80S

10

20

30

STD

40

60

XS

80

100

120

140

160XXS

6

1/8"

10.29


1.24

1.73

2.41




1.73

1.73


2.41

2.41






8

1/4"

13.72


1.65

2.24

3.02




2.24

2.24


3.02

3.02






10

3/8"

17.15


1.65

2.31

3.20




2.31

2.31


3.20

3.20






15

1/2"

21.34

1.65

2.11

2.77

3.73




2.77

2.77


3.73

3.73




4.78

7.47

20

3/4"

26.67

1.65

2.11

2.87

3.91




2.87

2.87


3.91

3.91




5.56

7.82

25

1"

33.4

1.65

2.77

3.38

4.55




3.38

3.38


4.55

4.55




6.35

9.09

32

1 1/4"

42.16

1.65

2.77

3.56

4.85




3.56

3.56


4.85

4.85




6.35

9.70

40

1 1/2"

48.26

1.65

2.77

3.68

5.08




3.68

3.68


5.08

5.08




7.14

10.16

50

2"

60.33

1.65

2.77

3.91

5.54




3.91

3.91


5.54

5.54




8.74

11.07

65

2 1/2"

73.03

2.11

3.05

5.16

7.01




5.16

5.16


7.01

7.01




9.52

14.02

80

3"

88.9

2.11

3.05

5.49

7.62




5.49

5.49


7.62

7.62




11.13

15.24

90

3 1/2"

101.6

2.11

3.05

5.74

8.08




5.74

5.74


8.08

8.08






100

4"

114.3

2.11

3.05

6.02

8.56




6.02

6.02


8.56

8.56


11.13


13.50

17.12

125

5”

141.3

2.77

3.40

6.55

9.52




6.55

6.55


9.52

9.52


12.70


15.90

19.05

150

6"

168.28

2.77

3.40

7.11

10.97




7.11

7.11


10.97

10.97


14.30


18.20

21.95

200

8"

219.08

2.77

3.76

8.18

12.70


6.35

7.04

8.18

8.18

10.30

12.70

12.70

15.10

18.20

20.60

23.00

22.22

250

10"

273.05

3.40

4.19

9.27

12.70


6.35

7.80

9.27

9.27

12.70

12.70

15.09

18.26

21.44

25.40

28.58


300

12"

323.85

3.96

4.57

9.52

12.70


6.35

8.38

9.52

10.31

14.27

12.70

17.48

21.44

25.40

28.58

33.32


350

14"

355.6

3.98

4.78



6.35

7.92

9.52

9.52

11.13

15.09

12.70

19.05

23.83

27.79

31.75

35.71


400

16"

406.4

4.19

4.78



6.35

7.92

9.52

9.52

12.70

16.66

12.70

21.44

26.19

30.96

36.53

40.49


450

18"

459.2

4.19

4.78



6.35

7.92

11.13

9.52

14.27

19.05

12.70

23.83

29.36

34.92

39.67

45.24


500

20"

508

4.77

5.53



6.35

9.52

12.70

9.52

15.09

20.62

12.70

26.19

32.54

38.10

44.45

50.01


550

22"

558.8

4.77

5.53



6.35

9.52

12.70

9.52

15.87

22.22

12.70

28.57

34.92

41.27

47.62

53.97


600

24"

609.6

5.54

6.35



6.35

9.52

14.70

9.52

17.48

24.61

12.70

30.96

38.89

46.02

52.37

59.94


650

26"

660.4





7.92

12.70


9.52



12.70







700

28"

711.2





7.92

12.70

15.88

9.52



12.70







750

30"

762

6.35

7.92



7.92

12.70

15.88

9.52



12.70







800

32"

812.8





7.92

12.70

15.88

9.52



12.70







Surface Conditions of Monel 400 Superalloy Steel Tube

Womic Steel offers a wide range of surface finishes to meet various marine, chemical, and critical service applications.

Surface Type

Description

Annealed & Pickled (AP Finish)

Standard industrial finish – matte, oxide-free after acid treatment. Suitable for most marine and chemical applications.

Bright Annealed (BA Finish)

Mirror-like surface obtained through controlled atmosphere annealing.

Polished Finish (180#, 240#, 320#, 400#)

Smooth mechanical finish suitable for high-purity and instrumentation applications.

Cold Worked Finish

As-drawn finish with higher strength (cold worked condition).

Passivated Finish

Surface chemically treated to enhance corrosion protection.

Each Monel 400 Superalloy Steel Tube surface is inspected for uniform appearance, absence of pits, and consistent finish quality.

Testing and Inspection of Monel 400 Superalloy Steel Tube

Every Monel 400 Superalloy Steel Tube undergoes comprehensive inspection in accordance with ASTM B163, ASTM B165, and EN 10216-5 standards to guarantee reliability and performance:

Test / Inspection

Description

Applicability

Visual & Dimensional Inspection

Surface, roundness, and thickness checked.

100%

Hydrostatic Pressure Test

100% tested for leakage and pressure resistance.

100%

Eddy Current Test (ECT)

Detects surface and sub-surface imperfections.

100%

Ultrasonic Test (UT)

Ensures internal integrity of the seamless structure.

Upon request

Positive Material Identification (PMI)

Confirms correct chemical grade (Ni ≥63%, Cu 28-34% verification).

100% (per heat)

Flattening & Flaring Tests

Evaluate ductility and deformation capability.

Per heat / batch

Hardness & Tensile Testing

Confirms mechanical compliance with ASTM standards.

Per heat / batch

Intergranular Corrosion Test (IGC)

ASTM G28 – validates resistance to intergranular corrosion.

Per heat / batch

Surface Roughness and Cleanliness Check

For polished or instrument tubes.

Upon request

Third-Party Inspection (SGS / BV / DNV / TUV)

Available upon customer request.

Upon request

These extensive tests ensure that every Monel 400 Superalloy Steel Tube from Womic Steel meets the highest international standards for reliability and longevity.

Applications of Monel 400 Superalloy Steel Tube

Monel 400 Superalloy Steel Tube is ideal for a wide variety of marine and chemical industries, offering long service life in demanding conditions:

Industry

Typical Applications

Marine & Shipbuilding

Seawater cooling systems, propulsion system tubing, ballast system instrumentation, hydraulic lines, exhaust gas scrubber tubing, shipboard piping systems (ship classification certifications available from ABS, BV, DNV, LR, GL, RINA, CCS, KR, NK).

Petrochemical & Refining

HF alkylation heat exchangers, hydrofluoric acid coolers and heaters, alkylate coolers, propane-propylene splitters, HF acid storage and transfer lines.

Chemical Processing

Brine heaters and coolers, chlor-alkali heat exchangers, salt evaporators, sulfuric acid coolers (deaerated), phosphoric acid heat exchangers, chemical injection lines.

Desalination Plants

Brine heaters, brine preheaters, multi-stage flash (MSF) evaporators, high-velocity brine systems, chemical injection lines.

Offshore Platforms

Seawater coolers, topside heat exchangers, firewater system heat exchangers, hydraulic control lines.

Power Generation

Coastal power plant condensers, cooling water heat exchangers, auxiliary coolers, seawater intake systems.

Hydrofluoric Acid Service

HF storage and transport heat exchangers, fluorochemical production, fluorine-containing process streams, alkylation unit components.

Pulp & Paper

Black liquor evaporators, digester heat exchangers, recovery boiler heat exchangers.

Chlorine Production

Brine heaters, evaporators, caustic service heat exchangers.

Oil & Gas

Seawater injection lines, chemical injection systems, hydraulic control lines, downhole components (limited sour service).

Propeller Shafts & Pump Components

Propeller shafts, pump impellers, valve stems, seawater pump components, marine hardware.

Monel 400 Superalloy Steel Tube Packing, Delivery, and Womic Steel's Transportation Advantage

Each Monel 400 Superalloy Steel Tube is securely packed and clearly labeled to ensure safe and efficient transport worldwide.

General packaging for local truck transport:
Bundle packing with woven fabric, iron strip bundle, plastic cap on two ends.

Hexagonal packaging:
Bundle packing with woven fabric, iron strip bundle, plastic cap on two ends.

Packaging for marine and seawater tubes:
Wooden crate with foam padding, individual tube separation, plastic end caps for export sea-worthy transport.

General packaging for products to be exported:
Wooden box for export sea-worthy transport.

Packaging for instrumentation and coiled tubing:
Wooden box or steel reels with protective wrapping for export sea-worthy transport.

Packaging for HF alkylation tubes:

Wooden crate with moisture barrier, individual tube separation, plastic end caps, corrosion inhibitor.

Womic Steel's Shipping and Delivery Strengths on Monel 400 Superalloy Steel Tubes:

Direct cooperation with global shipowners ensures the most competitive freight rates.

Professional loading and securing teams guarantee damage-free shipment.

Efficient document preparation (EN 10204 3.1/3.2 certificates, MTR, marine classification certificates), minimizing customs delays.

Rapid delivery time — select sizes kept in ready stock.

Continuous cargo tracking and after-sales follow-up to ensure smooth arrival at destination.

Why Choose Womic Steel's Monel 400 Superalloy Steel Tube

Womic Steel is a trusted manufacturer and exporter specializing in Monel 400 Superalloy Steel Tubes, committed to delivering premium quality and professional service for marine and chemical applications.

Strict quality control under ISO 9001, ASME, and PED certification.

Marine certified – ABS, BV, DNV, LR, GL, RINA, CCS, KR, NK approvals available.

HF alkylation industry standard – premier material for hydrofluoric acid service.

Excellent seawater erosion resistance – outstanding performance at velocities up to 10 m/s.

Superior biofouling resistance – reduces maintenance and preserves flow efficiency.

Modern production lines and experienced technicians.

Complete testing, inspection, and documentation support.

Flexible customization and surface finishing options.

Fast production cycle and reliable global shipping.

Premium mill relationships – direct sourcing from Special Metals, VDM Metals.

Full traceability – from melt to final tube, complete certification package.

Coiled tubing capability – up to 500m continuous lengths for marine and chemical injection systems.

What'sapp

What'sapp

E-mail

E-mail

Wechat

Wechat

wechat