Overview
What is Nimonic 115?
Nimonic 115 is the highest-temperature grade in the wrought Nimonic family. It was developed for gas-turbine blades, where a part has to carry stress for thousands of hours at a temperature that would soften almost any steel. The alloy gets its strength from a very high volume fraction of γ′ Ni3(Al,Ti) precipitate, close to half the microstructure, backed by molybdenum in solid solution and by grain-boundary carbides and borides that resist creep cavitation.
The same γ′ content makes the alloy hard to produce. Nimonic 115 has a narrow hot-working window and a flow stress far above that of stainless steel. Its γ′ solvus sits close to the incipient melting point, so solution treatment has to be held inside a tight band. Nimonic 115 forgings are made to order by shops that run the grade regularly, and they are not a stock item.
Where Nimonic 115 fits. Choose it when the part has to survive above roughly 950 °C and creep-rupture life governs the design. Below that, Nimonic 105 and Waspaloy are easier to process. If the joint has to be welded, Nimonic 263 is the usual answer.
At a glance. Ni-Cr-Co superalloy. γ′ precipitation hardened. Continuous service to 1010 °C. Density 7.85 g/cm³. UTS 1277 MPa minimum. Difficult to weld. Supplied as wrought forgings.
Identification
Nimonic 115 designations and equivalents
Nimonic 115 appears in enquiries under several names. All of the following refer to the same nickel-chromium-cobalt superalloy, and Jiangyin Jiangnan Metal Co., Ltd. quotes and certifies against any of them.
| System | Designation | Scope |
|---|---|---|
| UNS | N07115 | Unified Numbering System, USA |
| Werkstoff / DIN | 2.4636 | German material number, the most consistently cited designation worldwide |
| British Standard | BS HR4 | Billet, bar, forgings and parts |
| AFNOR | NCK 15 ATD | French designation |
| AECMA | prEN 2196, prEN 2197 | European aerospace material specifications |
| Trade names | Nimonic® alloy 115, Alloy 115, Nimonic115 | NIMONIC® is a registered trademark of Special Metals Corporation |
| Jiangyin Jiangnan Metal Co., Ltd. is an independent forging factory and is not affiliated with Special Metals Corporation. Trademarks are referenced only to identify the alloy grade. | ||
Chemistry
Nimonic 115 chemical composition
The composition below is the specification range for Nimonic 115. Nickel is the balance, typically around 57 per cent. Aluminium plus titanium together reach roughly 9 to 10 per cent, which is what drives the alloy's γ′ content, and with it both the strength and the poor weldability.
- Ni balance 57%
- Cr 14.0–16.0%
- Co 13.0–15.5%
- Al 4.5–5.5%
- Ti 3.5–4.5%
- Mo 3.0–5.0%
- C, B, Zr, Si, Mn, Fe
| Element | Symbol | Min % | Max % | Role in the alloy |
|---|---|---|---|---|
| Nickel | Ni | Balance, about 57 | Austenitic matrix | |
| Chromium | Cr | 14.0 | 16.0 | Oxidation and hot-corrosion resistance |
| Cobalt | Co | 13.0 | 15.5 | Lowers the γ′ solvus and widens the working window |
| Aluminium | Al | 4.5 | 5.5 | γ′ former, alumina scale |
| Titanium | Ti | 3.5 | 4.5 | γ′ former |
| Molybdenum | Mo | 3.0 | 5.0 | Solid-solution strengthening |
| Carbon | C | 0.12 | 0.20 | Grain-boundary carbides |
| Boron | B | 0.010 | 0.025 | Grain-boundary strength and creep ductility |
| Zirconium | Zr | — | 0.15 | Grain-boundary strengthening |
| Silicon | Si | — | 1.0 | Residual |
| Manganese | Mn | — | 1.0 | Residual |
| Iron | Fe | — | 1.0 | Residual |
| Copper | Cu | — | 0.20 | Residual |
| Sulphur | S | — | 0.015 | Impurity, controlled for hot ductility |
| Lead | Pb | — | 0.0015 | Tramp element, embrittles grain boundaries |
Composition is verified by spectrometric analysis on every heat. The certified ladle and product analysis is reported on the EN 10204 certificate issued with each Nimonic 115 forging.
Mechanical data
Nimonic 115 mechanical properties
Room-temperature minimum values for Nimonic 115 in the fully heat-treated condition are shown below. Actual results depend on section size, test orientation and the exact heat-treatment cycle, and are reported on the certificate for each heat.
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength (UTS) | 1277 MPa min | 185 ksi min |
| Yield strength, 0.2% proof | 973 MPa min | 141 ksi min |
| Elongation (A5) | 38% min | 38% min |
| Density | 7.85 g/cm³ | 0.284 lb/in³ |
| Maximum continuous service temperature | 1010 °C | 1850 °F |
| Values are order minimums. Elevated-temperature tensile, stress-rupture and hardness testing can be added to the order. State the temperature and duration required at enquiry stage. | ||
Creep and rupture behaviour
Nimonic 115 is specified for its creep-rupture strength, not for its room-temperature tensile strength. The alloy still carries load where lower-γ′ grades have relaxed, which lets turbine components hold clearance and pre-load through long service intervals. If creep-rupture data forms part of the acceptance criteria, give the test temperature, stress and required life at enquiry stage, so the heat-treatment cycle and the test programme can be agreed before the material is released.
Physical data
Nimonic 115 physical properties
| Property | Condition | Value |
|---|---|---|
| Density | — | 7.85 g/cm³ (0.284 lb/in³) |
| Melting range | — | 1260–1315 °C (2300–2400 °F) |
| Specific heat | 20 °C | 444 J/kg·°C |
| Thermal conductivity | 20 °C | 10.6 W/m·°C |
| Electrical resistivity | 20 °C | 139 µΩ·cm |
| Structure | — | Austenitic FCC γ matrix with γ′ Ni3(Al,Ti) precipitate |
| Magnetic response | 20 °C | Essentially non-magnetic |
Thermal conductivity of 10.6 W/m·°C is roughly a fifth that of carbon steel. Allow for it when planning heating rates, quench response and machining coolant strategy on heavy Nimonic 115 sections.
Process route
Melting route and heat treatment of Nimonic 115
Melting
Nimonic 115 is a high-aluminium, high-titanium alloy, so it is melted under vacuum to keep oxide and nitride inclusions out of the ingot. The normal route is VIM plus ESR, vacuum induction melting followed by electroslag remelting, with VIM plus VAR double-melted stock available where an aerospace specification calls for it. State the required melt practice on the enquiry, because it affects both price and lead time.
Heat treatment
Nimonic 115 is supplied in the fully heat-treated condition unless the order specifies otherwise. The standard cycle is a two-stage solution treatment plus age:
Standard Nimonic 115 heat treatment
Stage 1, solution treat 1½ h at 1190 °C, air cool.
Stage 2, age 6 h at 1100 °C, air cool.
Stage 1 takes the γ′ into solution and homogenises the structure. Stage 2 re-precipitates it as the fine, stable dispersion that carries the creep strength. Both stages air cool. Because the γ′ solvus sits close to the incipient melting temperature, furnace uniformity and thermocouple placement decide the result: overshoot risks incipient melting, and undershoot leaves the structure only partly solutioned. Furnace charts are retained and issued with the certificate on request.
Manufacturing
Forging, machining and welding Nimonic 115
Forging
Nimonic 115 is one of the harder wrought superalloys to forge. The high γ′ volume fraction gives a narrow working window and a high flow stress, so reductions are taken in controlled passes with frequent reheats, and both billet and die temperatures are held closely. Open-die forging and ring rolling are the usual routes at the sizes used in turbines and valves.
Jiangyin Jiangnan Metal Co., Ltd. forges Nimonic 115 on its own presses and ring mill in Jiangyin, Jiangsu, working from the customer's drawing or from finished dimensions plus a machining allowance.
Machining
Nimonic 115 work-hardens quickly and conducts heat poorly, so it machines like other high-γ′ nickel alloys. Use rigid setups, positive rake, heavy and well-directed coolant, low surface speed and a positive uninterrupted feed. A dwelling tool rubs instead of cutting, which glazes the surface and hardens the layer the next pass has to remove. On complex parts, a forged near-net preform cuts both the machining time and the material lost as chips.
Welding
Nimonic 115 is generally regarded as difficult to weld. Its combined aluminium and titanium content of roughly 9 to 10 per cent makes it highly susceptible to strain-age cracking during post-weld heat treatment, so fusion welding is not recommended for structural joints. Where a welded joint is unavoidable, Nimonic 263 was developed for weldability and formability and is the usual substitution.
Degrease Nimonic 115 thoroughly after forming or machining. Sulphur-bearing and lead-bearing lubricant residues left on the surface embrittle the grain boundaries during later high-temperature exposure.
What we make
Nimonic 115 forged product forms and sizes
Every Nimonic 115 forging is made to order against a drawing or a dimensional specification. There is no fixed catalogue. The forms below are the ones ordered most often.
Seamless rolled rings
Ring-rolled Nimonic 115 for turbine casings, spacers, seal rings and bearing housings.
Discs and blanks
Forged discs, turbine disc preforms, blade-root blanks and pancake forgings.
Shafts and spindles
Solid and stepped shafts, spindles, eccentric shafts and crankshaft preforms.
Flanges
Weld-neck, blind, slip-on and special-profile Nimonic 115 flanges to drawing.
Bars
Forged round, square and flat bar for onward machining.
Sleeves and bushings
Hollow forgings, sleeves, bushings and bored blanks.
Tube sheets and blocks
Forged tube sheets, tube plates and heavy forged blocks.
Valve components
Valve bodies, seats, seat rings, stems and nozzle blanks.
| Form | Size range | Notes |
|---|---|---|
| Seamless rolled rings | OD 200–3000 mm | Wall and height to drawing |
| Forged discs | OD up to 1500 mm | Solid or bored |
| Forged round bar | Ø 20–800 mm | Rough turned or black |
| Shafts | Length up to 6000 mm | Stepped profiles available |
| Unit weight | 5–5000 kg | Heavier by enquiry |
| Delivery condition | Solution treated and aged | Or as agreed on the order |
| Surface | Black, shot blasted or rough machined | Machining allowance to drawing |
Beyond Nimonic 115 forgings, the same routes are used for Nimonic 105, Nimonic 90, Nimonic 80A, Waspaloy, Inconel 718 and the other grades listed in the nickel alloy index.
Where it is used
Nimonic 115 applications by industry
| Industry | Typical Nimonic 115 forgings |
|---|---|
| Aero and industrial gas turbines | Turbine disc preforms, blade-root blanks, seal and spacer rings, casing rings, shafts |
| High-output reciprocating engines | Exhaust-valve blanks, valve seat inserts, turbocharger components |
| Power generation | Rotor components, boiler tube supports, generator and nitrogen-generator parts |
| Oil, gas and subsea | Wellhead and Christmas-tree components, deepwater production hardware, compressor parts |
| Valves and flow control | Bodies, seats, seat rings, stems and blocks for ball, gate, globe, check and plug valves |
| Pressure equipment | Forged flanges, tube sheets, shell-and-tube heat exchanger parts, air receivers |
| Process plant | Columns and towers, tanks, silos, preheaters, process modules, crystalliser equipment |
| Nuclear | Nozzle forgings, support structures, high-temperature hardware |
| Heavy industry | Die-casting inserts and cores, forging rolls, wheels, manifolds, gearbox and drive parts |
| Marine and shipbuilding | High-temperature exhaust and propulsion components |
Quality
Testing and certification for Nimonic 115 forgings
Nimonic 115 goes into components where a subsurface defect cannot be recovered in service. The NDT scope is therefore agreed before production starts. Jiangyin Jiangnan Metal Co., Ltd. tests and documents to the standards below.
| Check | Standard | Notes |
|---|---|---|
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 | Acceptance class stated on the order |
| Chemical analysis | Spectrometric, per heat | Ladle and product analysis reported |
| Mechanical testing | Tensile, elongation, reduction of area | Elevated-temperature testing on request |
| Hardness | Brinell or Rockwell | Location and count to specification |
| Grain size and microstructure | ASTM E112 | On request |
| Surface NDT | Dye penetrant (PT) | On request |
| Dimensional report | Against customer drawing | Issued with every shipment |
| Material certificate | EN 10204 3.1 | Mill certificate, standard supply |
| Third-party certificate | EN 10204 3.2 | Countersigned by an independent inspection body |
Third-party witness inspection and stage release by an independent body can be arranged when the order requires it. Nominate the inspection body at enquiry stage so the inspection and test plan can be issued with the order confirmation.
Selection
Nimonic 115 compared with related superalloys
The table below places Nimonic 115 against the grades it is most often weighed against. Service temperatures are indicative ceilings for continuous operation. The real limit for a component depends on stress, required life and environment.
| Alloy | Strengthening | Indicative max service | Forgeability | Weldability | Typical use |
|---|---|---|---|---|---|
| Nimonic 115 | γ′ (high Al+Ti) plus Mo | 1010 °C | Difficult | Poor | Highest-temperature turbine parts |
| Nimonic 105 | γ′ plus Mo | 950 °C | Moderate | Poor | Turbine blades and discs |
| Nimonic 90 | γ′ plus Co | 920 °C | Good | Fair | Blades, rings, hot-work tooling |
| Nimonic 80A | γ′ | 815 °C | Good | Fair | Exhaust valves, fasteners, rings |
| Nimonic 263 | γ′ (low Al+Ti) plus Mo | 850 °C | Good | Good | Fabricated and welded hot sections |
| Nimonic 75 | Solid solution | 925 °C | Very good | Good | Low-stress, oxidation-limited parts |
| Waspaloy | γ′ plus Mo and Co | 760 °C | Moderate | Fair | Turbine discs, shafts, fasteners |
| Inconel 718 | γ″ (Nb) plus γ′ | 650 °C | Good | Good | Discs, casings, oil and gas hardware |
| Indicative values for grade selection only. Confirm against the applicable design code and the component's own stress and life requirement. | |||||
Nimonic 115 or Nimonic 105?
Both are γ′-hardened Ni-Cr-Co alloys, but Nimonic 115 carries more aluminium and titanium. That gives roughly 60 °C more service ceiling and higher creep-rupture strength, at the cost of a narrower forging window and less tolerance of processing variation. If the design point sits below about 950 °C, Nimonic 105 is usually the cheaper and more predictable part to make.
Nimonic 115 or Waspaloy?
Waspaloy is a disc alloy chosen for balanced strength and processability in the 650 to 760 °C range. Nimonic 115 works far above that, but it does not replace Waspaloy at disc temperatures, where forgeability and fatigue behaviour matter more than creep resistance alone.
Questions
Frequently asked questions about Nimonic 115
What is Nimonic 115?
Nimonic 115 is a precipitation-hardened nickel-chromium-cobalt superalloy containing about 15% chromium, 14% cobalt, 5% aluminium, 4% titanium and 4% molybdenum, with nickel as the balance. It was developed for gas turbine blades and holds high creep-rupture strength and oxidation resistance in continuous service to 1010 °C (1850 °F).
What is the UNS number and Werkstoff number for Nimonic 115?
Nimonic 115 is designated UNS N07115 and Werkstoff (W.Nr.) 2.4636. It is also covered by BS HR4 for billet, bar, forgings and parts, by AFNOR as NCK 15 ATD, and by AECMA prEN 2196 and prEN 2197. Jiangyin Jiangnan Metal Co., Ltd. supplies forgings against any of these designations.
What is the maximum service temperature of Nimonic 115?
Nimonic 115 is rated for continuous service up to 1010 °C (1850 °F), the highest of the wrought Nimonic grades. The practical limit for a given part is lower and depends on the applied stress, the required life and the corrosiveness of the environment.
What is the chemical composition of Nimonic 115?
Nimonic 115 contains 14.0 to 16.0% chromium, 13.0 to 15.5% cobalt, 4.5 to 5.5% aluminium, 3.5 to 4.5% titanium, 3.0 to 5.0% molybdenum, 0.12 to 0.20% carbon and 0.010 to 0.025% boron, with silicon, manganese and iron each 1.0% maximum, zirconium 0.15% maximum, copper 0.20% maximum, sulphur 0.015% maximum, lead 0.0015% maximum, and nickel as the balance.
What heat treatment is used for Nimonic 115 forgings?
Nimonic 115 is given a two-stage treatment: solution treat for 1½ hours at 1190 °C and air cool, then age for 6 hours at 1100 °C and air cool. The ageing step precipitates the fine γ′ dispersion that carries the creep strength. Jiangyin Jiangnan Metal Co., Ltd. heat treats to this cycle or to the customer's own specification.
Is Nimonic 115 difficult to forge?
Yes. Nimonic 115 has one of the highest γ′ volume fractions of any wrought Nimonic grade, which narrows the hot-working window and raises flow stress well above that of steel. It needs powerful presses, close billet and die temperature control, and controlled reduction per pass. This is routine work for an open-die shop that runs nickel superalloys regularly.
Can Nimonic 115 be welded?
Nimonic 115 is generally regarded as difficult to weld. Its combined aluminium plus titanium content of around 9 to 10% makes it highly susceptible to strain-age cracking during post-weld heat treatment, so fusion welding is not recommended for structural joints. Designs normally use mechanical joining, or a more weldable grade such as Nimonic 263 where welding is unavoidable.
What is the difference between Nimonic 115 and Nimonic 105?
Both are γ′-hardened nickel-chromium-cobalt alloys, but Nimonic 115 carries more aluminium and titanium, giving higher creep-rupture strength and a higher service ceiling of about 1010 °C against roughly 950 °C for Nimonic 105. The trade-off is that Nimonic 115 is harder to hot work and less tolerant of processing variation.
What forms and sizes of Nimonic 115 forgings can you supply?
Jiangyin Jiangnan Metal Co., Ltd. produces Nimonic 115 as seamless rolled rings, forged rings, discs, blanks, shafts, spindles, flanges, round bars, sleeves, bushings, tube sheets, valve bodies and stems, nozzles and hollow forgings. Every part is made to the customer's drawing or dimensional specification rather than from a fixed catalogue.
What testing and certification do you provide with Nimonic 115 forgings?
Nimonic 115 forgings are ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388 as specified on the order, and supplied with an EN 10204 3.1 mill certificate or an EN 10204 3.2 certificate countersigned by a third-party inspection body. Chemical analysis, mechanical testing, hardness, grain size and dimensional reports are issued with the goods.
Where is your Nimonic 115 forging factory located?
Jiangyin Jiangnan Metal Co., Ltd. operates its open-die forging plant at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, about two hours from the port of Shanghai. Enquiries can be sent to sales@steelforgepieces.com or by phone to +86 189 2135 9659.
How do I request a quotation for Nimonic 115 forgings?
Send the drawing or the finished dimensions, the grade and applicable standard, the quantity, the required heat-treatment condition, the NDT scope and the certificate level to sales@steelforgepieces.com. A quotation with weight, lead time and delivery terms normally follows within one working day.
Who forges it
About Jiangyin Jiangnan Metal Co., Ltd.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, in the Yangtze delta forging cluster about two hours from the port of Shanghai.
The plant produces forged rings, seamless rolled rings, discs, shafts, flanges, sleeves, bushings, tube sheets, valve components and bars in carbon steel, alloy steel, tool steel, stainless steel and nickel-based superalloys. Nickel grades run regularly through the shop include the Nimonic series, Inconel, Incoloy, Hastelloy, Monel, Waspaloy and Udimet alloys.
Work is made to customer drawing, ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, and certified to EN 10204 3.1 or 3.2. Third-party inspection and witness release are arranged on request.
Request a quotation
Send your Nimonic 115 drawing for a quotation
Include the grade and standard, the drawing or finished dimensions, the quantity, the required heat-treatment condition, the NDT scope and the certificate level (EN 10204 3.1 or 3.2). We will come back with weight, price, lead time and delivery terms, normally within one working day.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory - Factory address
- No.1 Chengxiqiao Road,
Zhouzhuang Town, Jiangyin City,
Jiangsu Province, China - Telephone
- +86 189 2135 9659