UNS N09901 Forgings: Alloy 901 Rings, Discs, Shafts and Bars

Open-die forged and seamless rolled UNS N09901 to ASTM B637 and AMS 5660, with EN 10204 3.1 or 3.2 certification and ultrasonic testing to EN 10228-3.

What is UNS N09901?

UNS N09901 is the Unified Numbering System designation for a precipitation-hardenable nickel-iron-chromium superalloy developed for rotating gas turbine hardware. Two mechanisms give it strength. Titanium and aluminium precipitate a fine, coherent gamma-prime (γ′) phase during ageing. Molybdenum stays in solid solution and stiffens the matrix against dislocation movement at temperature.

The alloy contains roughly 36% iron, which sets it apart from fully nickel-based grades such as Waspaloy and Inconel 718. Iron lowers the raw material cost. It also widens the hot working window, which matters to a forge shop. The alloy has stayed in production for discs, shafts and rings for decades on that basis.

Continuous service temperature is about 600 °C (1110 °F). Above this the gamma-prime coarsens and creep strength drops faster than in higher-nickel grades, so designers move to Waspaloy, Nimonic 105 or Udimet 720.

Equivalent designations and standards

Trade names are the property of their respective owners and are listed here only to identify equivalent chemistry. Jiangyin Jiangnan Metal supplies to the UNS, ASTM and AMS designations above.

Chemical composition of UNS N09901

The limits below follow ASTM B637 and AMS 5660. Molybdenum at 5.0 to 6.5% supplies the solid-solution strengthening behind the creep performance. A composition table for N09901 without molybdenum is incomplete.

Composition limits differ between specification revisions and between ASTM, AMS and customer specifications. The governing purchase specification takes precedence. The actual heat analysis is reported on the EN 10204 certificate supplied with the order. Send us your specification and revision and we will confirm conformance before quoting.

Mechanical properties at elevated temperature

Typical tensile data for UNS N09901 in the solution treated and aged condition. Yield strength stays close to the room-temperature value up to about 700 °C, then drops sharply. This is why the service ceiling sits near 600 °C.

Typical values for guidance only, not guaranteed minima. Acceptance properties are agreed against the governing specification and section size, and are verified on test pieces taken from the forging itself.

Physical properties

Forging and heat treatment

Hot working

UNS N09901 is forged from a start temperature of about 1120 °C (2050 °F) and finished above about 950 °C (1740 °F). Reheating between passes is normal on heavy sections. The alloy work-hardens quickly once the temperature drops, so press schedules control reduction and temperature per heat instead of minimising the number of heats.

Solution treatment and ageing

The standard route is solution treatment followed by a two-stage age. Exact cycles are set by the governing specification and by section thickness:

• Solution treatment: about 1080 to 1095 °C (1975 to 2000 °F), held in proportion to section thickness, then oil or water quenched.
• Stabilising or first age: about 790 °C (1450 °F), air cooled.
• Final age: about 720 °C (1325 °F) for 24 hours, air cooled.

Forgings can be supplied as-forged for customers who heat treat in house, or solution treated and aged with the mechanical test results reported on the certificate.

Forging capability at Jiangyin Jiangnan Metal

Jiangyin Jiangnan Metal Co., Ltd. operates an open-die forging plant at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Jiangyin is in the Yangtze River Delta steel cluster, about 150 km from Shanghai port. Billet lead times and export freight times are both short as a result.

Product forms we forge in UNS N09901

• Seamless rolled rings Ring-rolled for continuous circumferential grain flow
• Forged discs Turbine discs, blanks, cover plates
• Forged shafts and spindles Straight, stepped and eccentric shafts
• Forged flanges Weld neck, blind, slip-on, special profiles
• Forged bushings Bored and trepanned hollows
• Forged sleeves and hollow bar Long hollows for machining down
• Forged tube sheets Heat exchanger and pressure vessel plates
• Forged round bar Peeled, ground or as-forged black
• Valve components Bodies, bonnets, stems, seat rings, blocks
• Near-net-shape forgings Reduced machining allowance to customer drawing

Applications for UNS N09901 forgings

• Gas turbinesTurbine discs, spacers, shafts, casings, seal rings and rotating hardware operating to 600 °C.
• AerospaceEngine discs, rings and fasteners where creep strength and thermal fatigue resistance govern.
• Power generationIndustrial gas turbine rotors, spacer rings, steam-side high-temperature components.
• Oil and gasSubsea and deepwater production hardware, wellhead and Christmas tree components, high-strength fasteners.
• Pressure equipmentTube sheets, forged flanges, nozzles and shells for heat exchangers, air receivers and columns.
• ValvesBodies, bonnets, stems, seat rings and blocks for ball, gate, globe, check and plug valves in hot service.
• Rotating equipmentCompressor shafts, gearbox components, spindles and gear blanks for power transmission.
• Chemical processingPump shafts, plunger pump parts, crystalliser components and reactor internals.
• Heavy machineryForged rolls, wheels, manifolds and crankshafts for mills, mixers, marine and pulp and paper plant.

Testing, inspection and certification

Every UNS N09901 forging leaves the works with documentation traceable to the heat number. The following are supplied as standard or on request:

• Chemical analysis. Ladle and, where specified, product analysis reported against the governing specification.
• Mechanical testing. Room-temperature and elevated-temperature tensile, hardness, impact and stress-rupture testing as specified.
• Ultrasonic testing. To EN 10228-3, SEP 1921, ASTM A388 or the customer's own acceptance class.
• Other NDT. Dye penetrant to ASTM E165, magnetic particle where applicable, and dimensional inspection reports.
• Grain size and microstructure. ASTM E112 grain size, macro-etch and micro examination on request.
• Certification. EN 10204 type 3.1 as standard, or type 3.2 counter-signed by a third-party body such as TÜV, BV, DNV, SGS or Lloyd's Register.

UNS N09901 compared with other superalloys

Buyers usually compare N09901 with Inconel 718 and Waspaloy. The choice comes down to temperature capability against cost and forgeability.

We also forge Waspaloy, Incoloy 925, Inconel 625 and Nimonic 901. If the grade is still open, we can quote alternatives side by side.

How to request a UNS N09901 quotation

Send a drawing or a size list to sales@steelforgepieces.com. Quotations normally go out within 24 hours. Including the following avoids a round of questions:

1. Grade and governing specification, with revision. For example ASTM B637 UNS N09901, or AMS 5660.
2. Product form and finished dimensions, or a drawing in PDF, DWG or STEP.
3. Quantity and required delivery date.
4. Supply condition: as-forged, rough machined, or solution treated and aged.
5. Testing and NDT requirements, including the ultrasonic acceptance class.
6. Certification type, EN 10204 3.1 or 3.2, and the third-party body if 3.2.
7. Destination port and Incoterms.

Frequently asked questions about UNS N09901

Contact the forging factory

Jiangyin Jiangnan Metal Co., Ltd. quotes UNS N09901 forgings from a drawing or from a simple size list. Technical questions about grade selection, supply condition or ultrasonic acceptance classes are welcome before you fix a specification.

Page last reviewed 31 August 2026 by the technical sales team at Jiangyin Jiangnan Metal Co., Ltd. Technical data is compiled from published ASTM B637 and SAE AMS 5660 limits and from standard Alloy 901 datasheets, and is given for guidance. It does not replace the governing purchase specification or the mill certificate issued with your order.