Nimonic 901 Alloy

Nimonic 901 (UNS N09901 / W.Nr. 2.4662) is a nickel-iron-chromium superalloy developed for high-strength applications operating under elevated temperatures and cyclic loading conditions. The alloy obtains its exceptional mechanical properties through precipitation hardening of gamma-prime (γ’) phases formed by titanium and aluminum additions.

Compared with conventional stainless steels and many heat-resistant alloys, Nimonic 901 maintains excellent tensile strength, creep resistance, and fatigue life at temperatures up to approximately 650°C. These characteristics make it a preferred material for aerospace propulsion systems, gas turbines, power generation equipment, and other critical rotating machinery.

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Nimonic 901 At a Glance

Key Attribute	Value
Alloy Name	Nimonic 901
UNS Number	N09901
Werkstoff Number	2.4662
Material Type	Nickel-Iron-Chromium Superalloy
Strengthening Mechanism	Gamma Prime (γ’) Precipitation Hardening
Density	8.14 g/cm³
Melting Range	1280 – 1345°C
Max Service Temperature	Up to 650°C
Main Strength	Creep & Fatigue Resistance
Typical Forms	Bar, Forging, Ring, Disc, Plate, Billet
Main Applications	Aerospace Turbines, Shafts, Rotors, Fasteners
Key Standards	AMS 5660 / AMS 5661

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Features of Nimonic 901

• Excellent creep rupture strength up to 650°C
• High fatigue and low-cycle fatigue resistance
• Outstanding stress rupture properties
• Good oxidation resistance in elevated-temperature environments
• Excellent structural stability during long-term exposure
• High tensile and yield strength after age hardening
• Suitable for highly stressed rotating components
• Proven performance in aerospace and gas turbine applications
• Good forgeability and machinability in solution-treated condition
• Available in multiple aerospace-grade specifications

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Chemical Composition of Nimonic 901

Element	Content (%)
Nickel (Ni)	40.0 – 45.0
Iron (Fe)	Balance
Chromium (Cr)	11.0 – 14.0
Molybdenum (Mo)	5.0 – 6.5
Titanium (Ti)	2.35 – 3.10
Aluminum (Al)	0.20 – 0.60
Cobalt (Co)	≤ 1.00
Manganese (Mn)	≤ 0.50
Silicon (Si)	≤ 0.40
Copper (Cu)	≤ 0.50
Carbon (C)	≤ 0.10
Sulfur (S)	≤ 0.015
Boron (B)	≤ 0.010

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Physical Properties of Nimonic 901

Property	Value
Density	8.14 g/cm³
Melting Range	1280 – 1345°C
Electrical Resistivity	1.12 μΩ·m (20°C)
Thermal Conductivity	11.5 W/m·K (20°C)
Specific Heat Capacity	435 J/kg·K
Modulus of Elasticity	205 GPa

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Mechanical Properties of Nimonic 901

Age Hardened Condition

Property	Metric Value
Tensile Strength	1250 – 1450 MPa
Yield Strength (0.2% Offset)	850 – 1050 MPa
Elongation	10 – 18%
Hardness	HB 320 – 390

Actual values vary depending on product form, heat treatment, and specification.

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Corrosion Resistance

Nimonic 901 demonstrates good resistance to oxidation and scaling in elevated-temperature atmospheres. The chromium content forms a stable protective oxide layer that helps reduce surface degradation during prolonged exposure to hot gases.

The alloy provides:

• Good oxidation resistance up to approximately 800°C
• Resistance to thermal fatigue cracking
• Good resistance to combustion gas environments
• Stable surface protection during cyclic heating
• Better high-temperature oxidation resistance than many low-alloy steels

For highly aggressive chloride-containing or reducing acid environments, corrosion-resistant nickel alloys such as Hastelloy grades may be more suitable.

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High Temperature Performance

The primary advantage of Nimonic 901 is its ability to retain mechanical strength under prolonged high-temperature loading.

Key performance benefits include:

• Excellent creep rupture resistance to 650°C
• Superior fatigue strength under cyclic loading
• Resistance to stress relaxation
• Good dimensional stability
• Strong microstructural stability during long-term service
• Reliable performance in rotating aerospace components

These properties make Nimonic 901 particularly valuable for turbine engine applications where both high temperature and high centrifugal stress are present.

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Available Forms

J&A Alloy supplies Nimonic 901 in various product forms:

• Round Bar
• Forged Bar
• Billet
• Disc Forgings
• Ring Forgings
• Shaft Forgings
• Plate
• Sheet
• Block
• Custom Machined Components

Available according to customer drawings and aerospace specifications.

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Applications of Nimonic 901

Nimonic 901 is widely used in industries requiring exceptional strength and fatigue resistance at elevated temperatures.

Aerospace

• Turbine discs
• Compressor discs
• Shafts
• Rotors
• Engine fasteners
• Gas turbine components

Power Generation

• Turbine hardware
• Rotating equipment
• High-temperature fasteners

Industrial Gas Turbines

• Rotor assemblies
• High-stress structural parts
• Hot section support components

Defense

• Aircraft engine systems
• Missile propulsion components

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Nimonic 901 vs Other Nickel Alloys

Alloy	Main Strength	Typical Service Temperature	Typical Applications
Nimonic 901	Excellent Creep & Fatigue Strength	Up to 650°C	Turbine Discs, Shafts, Rotors
Inconel 718	Strength & Corrosion Resistance	Up to 700°C	Aerospace, Oil & Gas Components
Nimonic 80A	Oxidation Resistance	Up to 815°C	Exhaust Valves, Turbine Parts
Waspaloy	Superior High-Temperature Strength	Up to 870°C	Aircraft Turbine Components

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Welding & Fabrication

Forming

Nimonic 901 can be hot worked successfully using conventional forging practices. Controlled temperatures are required to maintain optimal grain structure.

Machining

• Best machined in solution-treated condition
• Use rigid tooling
• Employ low cutting speeds and positive feed rates
• Carbide tooling is recommended

Welding

The alloy can be welded using GTAW and other fusion welding processes. Post-weld heat treatment is generally required to restore precipitation-hardened properties and achieve optimum mechanical performance.

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Standards & Equivalent Grades

Standard	Designation
UNS	N09901
Werkstoff	2.4662
AMS	AMS 5660
AMS	AMS 5661
BS HR	Nimonic 901

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Frequently Asked Questions

What is Nimonic 901?

Nimonic 901 is a precipitation-hardened nickel-iron-chromium superalloy designed for high-strength applications operating at temperatures up to approximately 650°C.

What is the UNS number for Nimonic 901?

The UNS designation is UNS N09901.

Is Nimonic 901 stronger than Inconel 718?

Both alloys provide excellent strength. Nimonic 901 is particularly valued for fatigue resistance and turbine disc applications, while Inconel 718 offers broader corrosion resistance and weldability.

What heat treatment is used for Nimonic 901?

The alloy is typically solution treated and then age hardened to develop its full mechanical properties.

What industries use Nimonic 901?

Aerospace, power generation, gas turbines, defense, and industrial rotating equipment manufacturers commonly use Nimonic 901.

Can Nimonic 901 be forged?

Yes. Nimonic 901 has excellent forging characteristics and is commonly supplied as forged bars, discs, rings, and shafts.

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Why Choose J&A Alloy

Reliable Superalloy Expertise

J&A Alloy specializes in nickel-based alloys, superalloys, and high-performance materials for demanding industries worldwide.

Strict Quality Control

• 100% PMI inspection
• Chemical composition verification
• Mechanical testing
• Ultrasonic testing
• Third-party inspection available

Complete Documentation

• EN 10204 3.1 Certificate
• Mill Test Certificate (MTC)
• Material Traceability
• NACE compliance documentation when required

Flexible Manufacturing

• Custom dimensions
• Precision machining
• Forging services
• Small and large production runs

Global Export Experience

Supplying aerospace, energy, oil & gas, and industrial customers across North America, Europe, the Middle East, and Asia.