Monel 401 (UNS N04401 / W.Nr. 2.0842) Steel Pipe

Introduction

Monel 401 is a nickel-copper alloy known for its exceptional resistance to corrosion and oxidation. It is particularly effective in marine and chemical environments, making it a popular choice for various industrial applications. This guide provides an overview of Monel 401, including its properties, applications, and specifications.

Properties of Monel 401

Chemical Composition

Monel 401 primarily consists of nickel and copper with small amounts of other elements. Below is the typical chemical composition:

Element	Composition (%)
Nickel (Ni)	43.0 – 47.0
Copper (Cu)	52.0 – 56.0
Iron (Fe)	1.5 max
Manganese (Mn)	1.0 max
Carbon (C)	0.15 max
Silicon (Si)	0.5 max
Sulfur (S)	0.024 max

Mechanical Properties

Monel 401 offers a unique combination of strength and ductility. Key mechanical properties include:

Property	Value
Tensile Strength	65 ksi (448 MPa)
Yield Strength	25 ksi (172 MPa)
Elongation	40%
Hardness	85 HRB

Physical Properties

Monel 401 maintains its properties across a wide temperature range:

Property	Value
Density	8.80 g/cm³
Melting Point	1300-1350°C (2370-2460°F)
Specific Heat	0.104 Btu/lb·°F (437 J/kg·K)
Electrical Resistivity	0.330 µΩ·m
Thermal Conductivity	21.8 W/m·K

Applications of Monel 401

Monel 401 is used in various industries due to its excellent corrosion resistance and mechanical properties. Common applications include:

Marine Engineering: Components exposed to seawater, such as propeller shafts, pump shafts, and seawater valves.
Chemical Processing: Equipment and piping that handle corrosive chemicals.
Oil and Gas: Tubing, valves, and other components in offshore drilling and production.
Power Generation: Heat exchangers and other equipment in nuclear and fossil fuel power plants.
Aerospace: Components that require high strength and corrosion resistance at elevated temperatures.

Specifications and Standards

Monel 401 pipes and other products are manufactured to meet specific standards and specifications:

ASTM B165: Standard specification for Monel 401 seamless pipes and tubes.
ASME SB165: American Society of Mechanical Engineers standard for Monel 401 pipes.
DIN 17751: German standard for nickel and nickel alloys, including Monel 401.

Availability

Monel 401 pipes are available in various sizes and forms, including:

Seamless Pipes: Typically used for high-pressure applications.
Welded Pipes: Suitable for lower-pressure applications and larger diameters.
Custom Shapes and Sizes: Can be manufactured to meet specific project requirements.

Example Sizes

Nominal Pipe Size (NPS)	Outside Diameter (OD)	Wall Thickness	Weight (lb/ft)
1/2″	0.840″	0.109″	0.85
1″	1.315″	0.133″	1.68
2″	2.375″	0.154″	3.66
4″	4.500″	0.237″	10.79

Conclusion

Monel 401 (UNS N04401 / W.Nr. 2.0842) is a versatile nickel-copper alloy offering excellent corrosion resistance, strength, and durability. It is widely used in marine, chemical, oil and gas, power generation, and aerospace industries. Understanding its properties and applications can help in selecting the right material for your specific requirements. Always consult with material specialists or suppliers to ensure compliance with your project’s specifications and standards.