What Nimonic 80A is
Key points
- Nickel-chromium alloy, 18 to 21 % Cr, age-hardened by gamma-prime Ni3(Al,Ti) precipitation.
- Holds tensile and creep-rupture strength to 815 °C. Oxidation resistance runs to about 1000 °C through a protective Cr2O3 film.
- Resists sulphur attack from combustion gas, which is why it dominates heavy-oil and marine engine exhaust valves.
- Non-magnetic. Weldable by TIG, MMA and MIG. Machinable with the techniques used for iron-based alloys.
- Jiangyin Jiangnan Metal forges it to customer drawing, not to a fixed size catalogue.
Nimonic 80A was developed as a replacement for valve steels and it remains the reference alloy wherever a part has to hold load in hot, sulphur-bearing gas. Titanium and aluminium additions precipitate a coherent gamma-prime phase during ageing. That precipitate, not cold work, is what carries the strength at temperature. Chromium at 18 to 21 % forms the Cr2O3 scale that keeps oxidation and sulphidation off the base metal.
Because the strength comes from precipitation rather than deformation, the forging route and the heat treatment record matter as much as the chemistry. A Nimonic 80A ring finished below its recommended temperature, or aged on an uncontrolled cycle, will pass the chemical analysis and fail the creep test. That is the failure mode our process controls are built around.
Chemical composition
Composition limits for Nimonic 80A per ASTM B637 and BS 3076 NA20, weight percent:
Chemical composition, Nimonic 80A / UNS N07080
wt %| Element | Ni | Cr | Ti | Al | C | Si | Cu | Fe | Mn | Co | B | Zr | S |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Nimonic 80A | Bal. | 18.0-21.0 | 1.8-2.7 | 1.0-1.8 | 0.10 max | 1.0 max | 0.2 max | 3.0 max | 1.0 max | 2.0 max | 0.008 max | 0.15 max | 0.015 max |
Melted by electric arc furnace with vacuum oxygen decarburisation and electroslag remelting (EAF + VOD + ESR). Heat analysis is reported on every EN 10204 3.1 certificate.
Mechanical properties
Room-temperature minima in the solution treated and aged condition:
Mechanical properties, solution treated + aged
20 °C| Property | Imperial | Metric | Basis |
|---|---|---|---|
| Tensile strength, Rm | 145 ksi min | 1000 MPa min | ASTM B637 |
| 0.2 % proof strength, Rp0.2 | 90 ksi min | 621 MPa min | ASTM B637 |
| Elongation, A | 20 % min | 20 % min | ASTM B637 |
| Hardness | n/a | 262-302 HB typ. | Typical |
Test pieces are taken and tested per the applicable product standard. These are acceptance minima, not design allowables. Refer to the governing specification for design data.
Physical properties
Physical properties, typical values
typical| Property | Value | Condition |
|---|---|---|
| Density | 8.19 g/cm³ | 20 °C |
| Melting range | 1360-1390 °C | n/a |
| Modulus of elasticity | approx. 222 GPa | 20 °C |
| Coefficient of thermal expansion | 12.7 x 10-6 /K | 20-200 °C |
| Thermal conductivity | 11.2 W/m·K | 20 °C |
| Specific heat capacity | 448 J/kg·K | 20 °C |
| Electrical resistivity | 1.24 µΩ·m | 20 °C |
| Magnetic response | Non-magnetic | All conditions |
Typical published values for wrought Nimonic 80A, given for guidance. Published modulus figures range from 190 to 222 GPa depending on source and condition, so confirm against the governing specification before using them in design calculations.
Heat treatment and forging practice
Standard heat treatment cycle
as supplied| Stage | Temperature | Time | Cooling |
|---|---|---|---|
| Solution treatment | 1080 °C (1976 °F) | 8 h | Air cool |
| Ageing | 700 °C (1292 °F) | 16 h | Air cool |
Furnace charts are retained and supplied with the certificate on request. For extended service above 750 °C a double-age cycle can be applied. Specify it at enquiry stage.
Forging window
Nimonic 80A is forged between roughly 1177 °C and 982 °C (2150 to 1800 °F). The workable range is narrow compared with steel. The alloy stiffens quickly as it cools and will crack if worked cold. Our practice is to plan reductions so that the final deformation still happens above about 1000 °C, reheating between passes rather than chasing the last few millimetres in a cooling billet. That is what produces the uniform fine grain the creep test depends on.
Nimonic 80A forged product forms
Every item below is open-die forged or ring-rolled to customer drawing. There are no catalogue sizes. Send dimensions and we forge to them.
Seamless rolled rings
Ring-rolled from upset and pierced billet, no weld seam.
To drawingForged discs & blanks
Solid discs for turbine and valve components.
To drawingForged round bars
Cogged and peeled or rough-turned bar stock.
To drawingForged shafts & spindles
Straight, stepped and eccentric shafts.
To drawingForged flanges
Weld-neck, blind, slip-on and special profiles.
To drawingSleeves & bushings
Hollow forged and bored, single or stepped bore.
To drawingTube sheets & plates
Forged and rolled plate for heat exchangers.
To drawingValve components
Stems, seat rings, bodies, blocks and bonnets.
To drawingBlocks & rectangles
Forged rectangular and square section stock.
To drawingTell us the finished weight and dimensions with your enquiry. We will confirm whether the piece is inside our own press capability or subcontracted through partner presses in the Jiangyin cluster.
Where Nimonic 80A forgings are used
Engine exhaust valves
The largest single application for the alloy. Marine and heavy-oil diesel engines burn fuel with high sulphur content, and Nimonic 80A resists the resulting sulphidation where valve steels do not.
Gas turbine hot section
Blades, rings, discs, casings and bolting for industrial and marine gas turbines working in the 650 to 815 °C band.
High-temperature fasteners
Studs, bolts and nuts that have to hold preload at temperature without relaxing: turbine casing joints, manifold flanges, aerospace fastening.
Nuclear plant internals
Boiler tube supports and structural components that need long-term creep stability and dimensional stability under thermal cycling.
Die casting tooling
Inserts and cores exposed to molten aluminium and repeated thermal shock, where thermal fatigue resistance outlasts hot-work tool steel.
High-temperature valves
Stems, seat rings and bodies for gate, globe, ball, check and plug valves in hot gas and steam service.
Pressure vessels & exchangers
Forged flanges, tube sheets and nozzles for shell-and-tube exchangers, air receivers, columns, towers and preheaters.
Oil & gas equipment
Subsea and deepwater production hardware, wellhead and Christmas tree components, compressor and generator parts.
Nimonic 80A compared with adjacent grades
The question we get asked most often is which nickel alloy to specify. The answer turns on temperature and on whether the gas path is corrosive.
Grade selection comparison
guide only| Grade | UNS | Strengthening | Max service | Rm typical | Best suited to |
|---|---|---|---|---|---|
| Nimonic 80A | N07080 | Gamma-prime Ni3(Al,Ti) | 815 °C | 1000 MPa | Hot, sulphur-bearing gas paths, exhaust valves |
| Nimonic 75 | N06075 | Solid solution | 925 °C | 750 MPa | Oxidation resistance where strength is secondary |
| Inconel 718 | N07718 | Gamma-double-prime Ni3Nb | 700 °C | 1275 MPa | High strength below 650 °C, weldable rotating parts |
| Inconel X-750 | N07750 | Gamma-prime Ni3(Al,Ti) | 815 °C | 1100 MPa | Springs and bolting, higher strength than 80A |
| Waspaloy | N07001 | Gamma-prime with Mo and Co | 870 °C | 1275 MPa | Aerospace turbine discs, highest hot strength here |
Typical values for comparison only. Grade selection rests with the design authority. We forge whichever grade you specify and will say so if we think the choice is wrong.
Nimonic 80A or Inconel 718?
Inconel 718 is stronger below about 650 °C and far easier to weld, which is why it dominates aerospace rotating hardware. Nimonic 80A holds strength and oxidation resistance better between 700 °C and 815 °C and resists sulphidation from combustion products. If the part sits in hot corrosive gas, specify 80A. If it needs maximum strength at moderate temperature and will be welded, specify 718. We forge both.
Testing, inspection and certification
Standards applied
per order| Activity | Standard | Notes |
|---|---|---|
| Product standard | ASTM B637 | Nickel alloy bars, forgings, forging stock |
| Equivalent specs | BS 3076 NA20, BS HR1, BS HR601, AFNOR NC20TA | Cross-referenced on certificate |
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 | Acceptance class stated by customer |
| Material certificate | EN 10204 3.1 | Standard on every order |
| Third-party inspection | EN 10204 3.2 | SGS, BV, TUV, Lloyd's, DNV on request |
| Dye penetrant / MPI | ASTM E165, ASTM E1444 | On request |
Certificates carry heat number, full chemical analysis, heat treatment record and mechanical test results, traceable to the forging.
How to order
-
Send a drawing or dimensions
Email sales@steelforgepieces.com with a drawing, sketch or finished dimensions and the quantity. State the grade as Nimonic 80A or UNS N07080.
-
Confirm the specification
Product standard, delivery condition, machining allowance, NDT acceptance class and certificate type (EN 10204 3.1 or 3.2). If you are not sure, send the application and we will propose them.
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Receive the quotation
Price, forging weight, lead time and packing, normally returned within 24 hours during Chinese working hours (GMT+8).
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Approve drawing and release
We issue a forging drawing showing allowances for your approval, then schedule production against certified Nimonic 80A stock.
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Inspection and shipment
Heat treatment, mechanical testing, ultrasonic inspection and certificate release, then despatch by sea or air from Shanghai.
Frequently asked questions
What is Nimonic 80A?
Nimonic 80A is a wrought, age-hardenable nickel-chromium superalloy strengthened by additions of titanium, aluminium and carbon. It contains 18 to 21 % chromium with nickel as balance, and holds tensile and creep-rupture strength at temperatures up to 815 °C (1500 °F). It is designated UNS N07080 and Werkstoff 2.4952 / 2.4631.
Is Nimonic 80A the same as UNS N07080?
Yes. Nimonic 80A, Alloy 80A, UNS N07080, W.Nr. 2.4952, W.Nr. 2.4631, BS 3076 NA20, BS HR1 and AFNOR NC20TA all describe the same nickel-chromium-titanium-aluminium alloy. Nimonic is a registered trade name. UNS N07080 is the generic designation used on material certificates.
Who supplies Nimonic 80A forged rings and discs?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges Nimonic 80A into seamless rolled rings, discs, shafts, flanges, sleeves, tube sheets, blocks and bars to customer drawings. Enquiries: sales@steelforgepieces.com or +86-189-2135-9659.
What is the heat treatment for Nimonic 80A?
The standard treatment is solution treatment for 8 hours at 1080 °C (1976 °F) followed by air cooling, then ageing for 16 hours at 700 °C (1292 °F) followed by air cooling. This precipitates the gamma-prime Ni3(Al,Ti) phase that gives the alloy its strength.
What are the mechanical properties of Nimonic 80A?
In the solution treated and aged condition, Nimonic 80A meets a minimum tensile strength of 1000 MPa (145 ksi), a minimum 0.2 % proof strength of 621 MPa (90 ksi) and a minimum elongation of 20 %. Typical hardness is 262 to 302 HB.
What temperature can Nimonic 80A be used at?
Nimonic 80A holds useful tensile and creep-rupture strength up to about 815 °C (1500 °F). Its protective chromium oxide (Cr2O3) film gives oxidation and scaling resistance up to roughly 1000 °C, although load-bearing strength falls sharply above 815 °C.
What standard are Nimonic 80A forgings supplied to?
Jiangyin Jiangnan Metal supplies Nimonic 80A forgings to ASTM B637, the standard covering precipitation-hardening nickel alloy bars, forgings and forging stock for moderate or high temperature service. Equivalent designations include BS 3076 NA20, BS HR1 and BS HR601.
What certification comes with Nimonic 80A forgings?
Every order ships with an EN 10204 3.1 mill certificate covering heat number, chemical analysis, heat treatment record and mechanical test results. EN 10204 3.2 certification with third-party inspection by SGS, BV, TUV, Lloyd's Register or DNV is available on request.
What is Nimonic 80A used for?
The largest single application is exhaust valves in internal-combustion engines, including marine and heavy-oil engines where resistance to sulphur in combustion gas matters. It is also used for gas turbine blades, rings, discs and bolts, high-temperature fasteners, nuclear boiler tube supports, and die casting inserts and cores.
Nimonic 80A vs Inconel 718, which should I use?
Inconel 718 is stronger below about 650 °C and is easier to weld, which is why it dominates aerospace rotating parts. Nimonic 80A holds its strength and oxidation resistance better between 700 °C and 815 °C and resists sulphidation from combustion gas, which is why it remains the standard choice for engine exhaust valves. Choose 718 for strength at moderate temperature, 80A for hot corrosive gas paths.
What is the forging temperature range for Nimonic 80A?
Nimonic 80A is forged between approximately 1177 °C and 982 °C (2150 to 1800 °F). Reheating is required if the workpiece falls below the finishing temperature, and reductions should be planned so that final deformation occurs above roughly 1000 °C to develop a uniform fine grain size.
Can you forge Nimonic 80A to my drawing?
Yes. Jiangyin Jiangnan Metal is an open-die forging factory working to customer drawings and specifications. Send a drawing or the dimensions, quantity, required standard and delivery condition to sales@steelforgepieces.com and a quotation is normally returned within 24 hours.
Standards referenced on this page
- ASTM B637, Precipitation-Hardening and Cold Worked Nickel Alloy Bars, Forgings, and Forging Stock for Moderate or High Temperature Service.
- BS 3076, Nickel and nickel alloys: bar. Designation NA20 for Nimonic 80A.
- EN 10204, Metallic products: types of inspection documents (3.1 and 3.2).
- EN 10228-3, Non-destructive testing of steel forgings: ultrasonic testing of ferritic or martensitic steel forgings.
- SEP 1921, Ultrasonic testing of steel bars and forgings, quality classes.
- ASTM A388, Ultrasonic Examination of Steel Forgings.
- DIN EN 10302, Creep resisting steels, nickel and cobalt alloys.
Page last reviewed by the technical team at Jiangyin Jiangnan Metal Co., Ltd. Property values are typical published data for wrought Nimonic 80A and are given for guidance. The governing purchase specification always takes precedence.