01What is Nimonic 75?
Nimonic 75, also written Alloy 75 and registered as UNS N06075 (Werkstoff 2.4951 and 2.4630), is a wrought nickel-chromium superalloy of the classic 80/20 type. Chromium runs 18 to 21 percent, titanium 0.2 to 0.6 percent and carbon 0.08 to 0.15 percent, with nickel making up the balance at roughly 72 to 78 percent.
It was introduced in the 1940s for turbine blades in the prototype Whittle jet engines, and it is the oldest member of the Nimonic family still in volume production. What keeps it in service is not strength. It is the combination of a tenacious chromium-oxide scale, genuinely easy fabrication, and a price that undercuts every age-hardening grade.
How it gets its properties
Nimonic 75 is strengthened by two mechanisms, and neither of them is precipitation hardening. Chromium dissolved in the nickel matrix provides solid-solution strengthening. Titanium combines with carbon to form fine MC-type carbides that sit on the grain boundaries and resist grain-boundary sliding at temperature. There is no aluminium of any consequence in the chemistry, so no gamma prime Ni3(Al,Ti) forms, and the alloy cannot be aged to higher strength.
That single fact drives everything else about the grade. Because there is no gamma prime, there is no strain-age cracking after welding, no ageing distortion to design around, no two-stage heat treatment to schedule, and no rapid loss of properties if a part sees an unplanned thermal excursion. The alloy simply anneals. For fabricated assemblies that run hot but carry little load, that predictability is worth more than the extra strength of Nimonic 80A.
The chromium oxide scale
At temperature, the 20 percent chromium forms a continuous, adherent Cr2O3 layer that starves the base metal of oxygen. The scale reforms if damaged and stays attached through thermal cycling, which is why Nimonic 75 survives repeated heating and cooling in furnace service where many stainless grades spall and waste away. Titanium contributes to scale adhesion.
Nimonic 75 is a solid-solution 80/20 Ni-Cr alloy (UNS N06075). It is not age hardenable. Use it for oxidation resistance and weldability up to about 1100 °C unstressed, or 815 °C under load. For higher strength at temperature, step up to Nimonic 80A, Nimonic 90 or Nimonic 263.
Jiangyin Jiangnan Metal Co., Ltd. supplies Nimonic 75 as forged product only: open-die forgings and seamless rolled rings. Forging closes casting porosity and aligns grain flow with the principal stress direction, which matters more in a low-strength alloy than it does in a high-strength one, because there is less margin to absorb a defect.
02Nimonic 75 designations and equivalents
Buyers meet this alloy under a dozen names depending on which standard the drawing was written to. All of the designations below describe the same base chemistry, with minor differences in tolerance bands and impurity limits between specifications.
| System | Designation | Scope |
|---|---|---|
| UNS (USA) | N06075 | Unified Numbering System |
| Werkstoff (Germany) | 2.4951, 2.4630 | Material number, all product forms |
| DIN | NiCr20Ti | DIN 17742, 17750, 17751, 17752 |
| British Standard | HR5 | Bar and forgings |
| British Standard | HR203, HR403, HR504 | Sheet, strip, tube and other forms |
| AMS | AMS 5683 | Bars, forgings and rings |
| AMS | AMS 5651 | Sheet, strip and plate |
| ISO | ISO 9723, 9724, 9725 | Nickel alloy bars, wire and forgings |
| AFNOR (France) | NC 20T | French national designation |
| JIS (Japan) | NCF 75 | Japanese heat-resisting alloy |
| AECMA (aerospace) | prEN 2293, 2294, 2302, 2306–2308, 2402, 2411 | European aerospace series |
| Trade names | Nimonic 75, Alloy 75, Haynes 75, Nicrofer 7520 | Producer brand names |
| Broadly similar | EI435 / ЭИ435 (RU), GH3030 (CN) | Comparable Ni-20Cr-Ti grades, not exact substitutes |
Table compiled by Jiangyin Jiangnan Metal Co., Ltd. from published alloy specifications. Cross-check limits against the governing specification before ordering a substitute grade.
ASTM B637 does not cover Nimonic 75. B637 applies to precipitation-hardening nickel alloy bars and forgings such as Inconel 718 and X-750. Nimonic 75 is a solid-solution grade and belongs under BS HR5, AMS 5683, DIN 17742/17752 or ISO 9723/9725. Drawings that call for “Nimonic 75 to ASTM B637” contain an error worth resolving with the design authority before the order is placed. We flag it at quotation stage rather than after the billet is cut.
03When to specify Nimonic 75, and when not to
Specify Nimonic 75 when
- The part runs hot in an oxidizing atmosphere but carries little sustained load: furnace fixtures, muffles, retorts, trays, baskets, radiant tubes, burner components.
- The assembly is welded or heavily formed, and post-weld strain-age cracking must be designed out rather than inspected for.
- Thermal cycling is severe and scale spalling is the failure mode you are fighting.
- The design needs oxidation resistance above the practical limit of 310 stainless but not the creep strength of an age-hardened grade.
- Cost matters and the strength of Nimonic 80A would be wasted.
Choose a different grade when
- Below about 550 °C. Austenitic stainless steels such as 321 and 347 usually do the same job for a fraction of the price. Nickel is only worth paying for above that.
- Sustained stress above 815 °C. Creep governs. Move to Nimonic 80A, Nimonic 90 or Nimonic 263.
- Carburizing or strongly reducing atmospheres. The Cr2O3 scale is not the right defence. Consider Inconel 601 or Alloy 602 CA, where aluminium forms a protective alumina scale.
- Aqueous acid corrosion. Nimonic 75 is a heat-resisting alloy, not a corrosion-resisting one. Use Hastelloy C-276, Alloy 59 or Inconel 625.
- Sulphidizing atmospheres. High-nickel alloys form low-melting Ni-S eutectics. Cobalt-base grades such as Haynes 188 or Haynes 25 handle sulphur better.
04Nimonic 75 compared with 80A, 90 and 263
These four grades share a nickel-chromium base and are routinely confused on drawings. The difference that matters is whether the alloy forms gamma prime. Nimonic 75 does not; the other three do.
| Attribute | Nimonic 75 | Nimonic 80A | Nimonic 90 | Nimonic 263 |
|---|---|---|---|---|
| UNS number | N06075 | N07080 | N07090 | N07263 |
| Werkstoff | 2.4951 / 2.4630 | 2.4952 | 2.4632 | 2.4650 |
| Nickel | Balance (~75) | Balance (~76) | Balance (~57) | Balance (~51) |
| Chromium | 18.0–21.0 | 18.0–21.0 | 18.0–21.0 | 19.0–21.0 |
| Cobalt | 2.0 max | 2.0 max | 15.0–21.0 | 19.0–21.0 |
| Titanium | 0.2–0.6 | 1.8–2.7 | 2.0–3.0 | 1.9–2.4 |
| Aluminium | 0.3 max | 1.0–1.8 | 1.0–2.0 | 0.6 max |
| Strengthening | Solid solution + MC carbides | Gamma prime | Gamma prime + Co | Gamma prime + Mo |
| Age hardenable | No | Yes | Yes | Yes |
| Tensile, room temp | ~750 MPa | ~1000 MPa | ~1240 MPa | ~970 MPa |
| Max stressed service | ~815 °C | ~815 °C | ~920 °C | ~850 °C |
| Weldability | Excellent, no strain-age cracking | Fair, strain-age risk | Fair, strain-age risk | Good for a gamma prime grade |
| Formability | Excellent | Moderate | Moderate | Good |
| Heat treatment | Single anneal, 1050 °C | Solution + age | Solution + age | Solution + age |
| Relative cost | Lowest | Medium | Highest | High |
| Typical use | Furnace parts, rings, casings, ducting | Turbine blades, bolting, discs | Turbine blades, hot rotating parts | Combustors, transition ducts |
Source: Jiangyin Jiangnan Metal Co., Ltd., consolidated from published Nimonic datasheets. Composition in weight percent. See also our Nimonic 80A and Nimonic 90 forging pages.
If the part is fabricated (welded, rolled, formed, and running hot with little load), Nimonic 75 is usually correct. If the part is machined from solid and carries load at temperature, you want gamma prime and should be looking at 80A or 90.
05Chemical composition of Nimonic 75
The table below is the specification range we forge to. Every heat is supplied with a ladle analysis on the mill certificate. Product analysis on the finished forging can be added on request.
| Element | Symbol | Weight % | Why it is there |
|---|---|---|---|
| Nickel | Ni | Balance (~72–78) | Austenitic matrix, thermal stability |
| Chromium | Cr | 18.0–21.0 | Forms the protective Cr2O3 scale; solid-solution strengthening |
| Titanium | Ti | 0.2–0.6 | Forms MC carbides that pin grain boundaries; aids scale adhesion |
| Carbon | C | 0.08–0.15 | Carbide former, deliberately controlled, not an impurity |
| Iron | Fe | 5.0 max | Tolerated residual from raw material |
| Manganese | Mn | 1.0 max | Deoxidiser, sulphur control |
| Silicon | Si | 1.0 max | Deoxidiser, minor scale benefit |
| Copper | Cu | 0.5 max | Residual limit |
| Cobalt | Co | 2.0 max | Residual limit |
| Aluminium | Al | 0.3 max | Held low; more would start gamma prime formation |
| Boron | B | 0.008 max | Grain-boundary trace |
| Zirconium | Zr | 0.15 max | Grain-boundary trace |
| Sulphur | S | 0.015 max | Impurity limit; embrittles grain boundaries |
| Lead | Pb | 0.0020 max | Impurity limit |
| Silver | Ag | 0.0005 max | Impurity limit |
| Bismuth | Bi | 0.0001 max | Impurity limit |
Source: Jiangyin Jiangnan Metal Co., Ltd., Nimonic 75 forging specification. Limits vary slightly between BS HR5, AMS 5683 and DIN 17742. State the governing specification on your enquiry and we will certify to it.
The low aluminium limit is the defining line between Nimonic 75 and Nimonic 80A. Raise aluminium to 1.0–1.8 percent and, with titanium, gamma prime begins to precipitate and the alloy becomes age hardenable: a different material with a different heat treatment, a different welding procedure and a different price.
06Mechanical properties of forged Nimonic 75
Nimonic 75 is supplied solution annealed. The values below are the room-temperature minima we certify on forged bar and ring product; results on the mill certificate normally sit comfortably above them. Acceptance values for a specific order are set by the governing specification and the ruling section, so confirm them at enquiry stage.
| Property | Metric | Imperial | Test method |
|---|---|---|---|
| Ultimate tensile strength | ≥ 740 MPa | ≥ 107 ksi | ASTM E8 / ISO 6892-1 |
| 0.2 % proof stress | ≥ 280 MPa | ≥ 41 ksi | ASTM E8 / ISO 6892-1 |
| Elongation, 5D | ≥ 30 % | ≥ 30 % | ASTM E8 |
| Reduction of area | ≥ 35 % | ≥ 35 % | ASTM E8 |
| Hardness | ≤ 230 HB | ≤ 20 HRC | ASTM E10 / E18 |
| Modulus of elasticity | ~206 GPa | ~29 900 ksi | Dynamic method |
| Modulus of rigidity | ~79 GPa | ~11 460 ksi | Dynamic method |
| Poisson's ratio | ~0.31 | ~0.31 | Calculated |
| Grain size | ASTM 4 or finer | ASTM 4 or finer | ASTM E112 |
Source: Jiangyin Jiangnan Metal Co., Ltd. Cold-worked material is supplied to different minima. Nimonic 75 can be strain hardened where a higher tensile is required, but the effect is lost on annealing and on exposure to service temperature.
Strength at elevated temperature
Short-term tensile strength falls steadily with temperature. The figures below are typical published values for solution-annealed material and are given for orientation only. They are not design allowables. Use the values in the governing specification or your own test data for design.
| Temperature | Tensile strength | 0.2 % proof stress | Comment |
|---|---|---|---|
| 20 °C / 68 °F | ~750 MPa | ~300 MPa | As-annealed baseline |
| 400 °C / 752 °F | ~660 MPa | ~230 MPa | Below the useful nickel range |
| 600 °C / 1112 °F | ~620 MPa | ~210 MPa | Creep starts to matter |
| 700 °C / 1292 °F | ~480 MPa | ~195 MPa | Creep governs design |
| 815 °C / 1500 °F | ~280 MPa | ~170 MPa | Practical stressed limit |
| 900 °C / 1652 °F | ~150 MPa | ~110 MPa | Unstressed service only |
Source: Jiangyin Jiangnan Metal Co., Ltd., consolidated from published Alloy 75 datasheets. Indicative values for material selection. Not design allowables.
Above roughly 600 °C, short-term tensile numbers stop being the right basis for design. Creep and stress-rupture life govern instead: a component that passes a tensile test at 750 °C can still deform unacceptably over 10 000 hours at a fraction of that stress. Ask your design authority for the rupture curve that applies to your service life, and tell us the acceptance criteria so the correct testing is quoted.
07Physical and thermal properties
These properties are set by the chemistry and do not change with heat treatment. We use them to convert your finished drawing into a forged billet weight, and to calculate thermal growth for parts that must hold clearance at temperature.
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.37 g/cm³ | 0.302 lb/in³ |
| Melting range | 1340–1380 °C | 2440–2515 °F |
| Specific heat, 20 °C | 461 J/kg·K | 0.110 Btu/lb·°F |
| Thermal conductivity, 20 °C | 11.7 W/m·K | 81 Btu·in/hr·ft²·°F |
| Electrical resistivity, 20 °C | 1.20 µΩ·m | 722 Ω·circ mil/ft |
| Mean CTE, 20–100 °C | 11.5 ×10−6/K | 6.4 µin/in·°F |
| Mean CTE, 20–500 °C | 14.0 ×10−6/K | 7.8 µin/in·°F |
| Mean CTE, 20–800 °C | 15.4 ×10−6/K | 8.6 µin/in·°F |
| Mean CTE, 20–1000 °C | 16.4 ×10−6/K | 9.1 µin/in·°F |
| Magnetic response | Non-magnetic; Curie point below −196 °C | |
Source: Jiangyin Jiangnan Metal Co., Ltd., consolidated from published Nimonic 75 datasheets. Typical values; confirm against the certificate of analysis for a specific heat.
At 15.4 ×10−6/K, a 2 000 mm Nimonic 75 ring grows about 24 mm on diameter between 20 °C and 800 °C. Furnace fixtures, retort seals and turbine casing clearances have to be designed around that. Use the thermal growth calculator in section 14 to check your own dimensions.
08Heat treatment and the Nimonic 75 temperature map
Nimonic 75 has one heat treatment: solution anneal, then air cool. There is no ageing step, no stabilising soak and no quench. This is the simplest thermal cycle of any Nimonic grade and one of the reasons the alloy stays in production.
Nimonic 75 process and service windows, 0 to 1400 °C. Source: Jiangyin Jiangnan Metal Co., Ltd.
| Product form | Temperature | Soak time | Cooling |
|---|---|---|---|
| Bar, forgings, rings | 1050 °C (1920 °F) | 30–60 min | Air cool |
| Sheet and thin section | 1050 °C (1920 °F) | 5–10 min | Air cool |
| Pre-weld anneal | 1050 °C (1920 °F) | 5–10 min | Air cool |
| Stress relief after machining | 870–900 °C | 1–2 h | Air cool, on request |
| Post-weld treatment | Not normally required. Specified only where corrosion conditions are severe or dimensional stability is critical. | ||
Source: Jiangyin Jiangnan Metal Co., Ltd. Furnace charts for every cycle are issued with the mill certificate. Heavy sections are soaked proportionally to the ruling section; see the soak calculator in section 14.
Holding Nimonic 75 in the 700–850 °C range will not raise its strength. With no aluminium to form gamma prime, all that happens is carbide coarsening at the grain boundaries, which reduces ductility without any strength gain. If a supplier offers “aged Nimonic 75”, the material is not Nimonic 75.
09Forging, welding and machining Nimonic 75
Hot working
Nimonic 75 is hot worked between roughly 1180 and 950 °C (2150 to 1740 °F). Forging must finish above 950 °C. Below that, the alloy work hardens quickly and grain-boundary cracking becomes likely, particularly at the corners and on the last passes of a heavy ring. Heavy sections are reheated between passes rather than pushed down cold, and a total reduction ratio of at least 3:1 from billet is used to close porosity and refine the grain.
Soaking matters as much as the forging itself. An under-soaked nickel billet has a cold core and a hot skin, and it cracks on the first blow. We soak to a uniform through-temperature and hold, which for a 600 mm diameter billet means several hours, not minutes.
Cold working
The alloy is readily cold formed, drawn and spun in the annealed condition, and can be strain hardened deliberately where a higher tensile is wanted. Work-hardening rate is higher than austenitic stainless, so allow intermediate anneals at 1050 °C for reductions beyond about 30 percent.
Welding
This is where Nimonic 75 earns its place. With no gamma prime, there is no strain-age cracking, so the alloy can be welded thick, welded repeatedly and repair welded without the elaborate procedure controls that 80A and 90 demand. Manual metal arc, gas tungsten arc, gas metal arc and submerged-arc processes are all used. Weld in the solution-annealed condition. Post-weld heat treatment is not normally necessary.
- Clean to bright metal. Nickel alloys are intolerant of sulphur, lead, zinc and grease, all of which cause hot cracking. Degrease with a sulphur-free solvent before striking an arc.
- Keep heat input moderate and interpass temperature low, below about 150 °C.
- Use a matching Ni-Cr filler, or Inconel 82 / Inconel 182 type consumables where the procedure allows.
- Back-purge with argon on full-penetration joints to protect the root from oxidation.
Machining
Nimonic 75 machines like a tough austenitic stainless rather than like a hardened superalloy. It is one of the easier nickel alloys to cut, but it still work hardens if you let the tool rub. The rules that matter: rigid setup, sharp tooling, positive rake, heavy constant feed and flood coolant. Never dwell, and never let the tool ride on a hardened skin from the previous pass. Machining parameters are in the tool set in section 14.
Where a part needs heavy metal removal, order it rough machined with an agreed allowance rather than as-forged. It removes the decarburised and oxidised skin, exposes any subsurface defect before you have spent money on finishing, and cuts your own tool wear. State the allowance you want on the enquiry.
10How Jiangyin Jiangnan Metal forges Nimonic 75
The route below runs on every Nimonic 75 order. Each stage produces a record that goes into the documentation pack, so the certificate you receive is traceable back to the heat number and the furnace chart.
Melt route and billet sourcing
Billet is accepted only against documented VIM plus ESR, VIM plus VAR, or EAF plus VOD plus ESR practice, with the melt certificate traceable to the heat number. Remelted material is specified where cleanliness and segregation control matter, which for Nimonic 75 means rotating parts and thick rings.
Billet conditioning and pre-heat
Surfaces are ground to remove defects, then the billet is soaked to a uniform through-temperature. Under-soaked nickel alloy cracks on the first blow, so soak time is set by section size, not by the clock.
Open-die forging, 1180 to 950 °C
Hydraulic press forging on a 5 000 tonne press, or hammer forging on 1, 3, 5 and 9 tonne hammers, with controlled reduction ratios and reheats between passes. Grain flow is directed along the hoop for rings and along the axis for shafts.
Ring rolling or upsetting to shape
Seamless rings are pierced and rolled to the finished envelope on 3 metre and 6 metre ring mills. Discs are upset and punched. Both routes give continuous grain flow that a ring cut from plate cannot match.
Solution annealing at 1050 °C
Charged into calibrated furnaces, soaked 30 to 60 minutes for bar and forgings, then air cooled. Time and temperature are recorded for the whole load and the chart is issued with the certificate.
Rough or finish machining
Supplied as-forged, rough machined to an agreed allowance, or finish machined to drawing tolerance. Rough machining before final inspection exposes subsurface defects early.
Non-destructive and mechanical testing
Ultrasonic testing to ASTM E2375, AMS 2154 or EN 10228-3, liquid penetrant to ASTM E1417, plus tensile, hardness and grain-size testing taken from integral or separately forged prolongations.
Marking, certification and packing
Hard-stamped heat number and part identification, EN 10204 3.1 certificate, or 3.2 counter-signed by a third party such as TUV, BV, SGS or Lloyd's Register, then seaworthy packing for export.
1, 3, 5 and 9 tonne open-die forging hammers · 5 000 tonne hydraulic press · 3 m and 6 m seamless ring rolling mills · calibrated heat-treatment furnaces · universal testing machine, impact tester, hardness tester, metallographic microscope and magnetic particle equipment on site.
11Nimonic 75 forged forms and size capability
Every part is made to your drawing or dimensional sketch. There is no fixed catalogue and no stock list. The ranges below cover what we forge regularly in Alloy 75.
| Forged form | Size range | Typical application |
|---|---|---|
| Seamless rolled rings | OD 200–6000 mm, H up to 1000 mm | Turbine casings, furnace rings, flange blanks |
| Contoured / profiled rings | OD 200–3000 mm | Stepped and shaped sections rolled to drawing |
| Forged discs | Dia. 150–2500 mm | Blind flanges, tube sheets, cover plates |
| Forged shafts and spindles | Dia. 80–1200 mm, L up to 12 000 mm | Furnace roller shafts, drive spindles |
| Round bars | Dia. 20–800 mm | Machining stock, fasteners, valve stems |
| Flat bars and blocks | Up to 800 × 1500 mm section | Valve bodies, manifolds, die blocks |
| Forged flanges | DN 15–1500, ASME B16.5 / B16.47 / EN 1092-1 | Hot gas piping, pressure vessels |
| Sleeves, bushings, hollow bars | OD 100–1200 mm | Wear sleeves, liners, bearing housings |
| Tube sheets and nozzles | Dia. up to 3000 mm | Heat exchangers, reformers, preheaters |
| Single-piece weight | 10 kg to 15 000 kg | Heavier pieces quoted case by case |
Source: Jiangyin Jiangnan Metal Co., Ltd. Delivery conditions: as-forged, solution annealed, rough machined to allowance, or finish machined to drawing.
12Where Nimonic 75 forgings are used
The common thread across every application below is heat plus an oxidizing atmosphere plus a fabricated structure. Where the load is high and sustained, the design will have moved to an age-hardening grade instead.
Industrial furnaces and heat treatment
The largest single use. Fixtures live through thousands of thermal cycles in air, carry almost no load, and fail by scaling rather than by creep, which is precisely the duty Nimonic 75 was optimised for.
Gas turbine engineering
Static and lightly loaded hot-section hardware, and the ancillary structures around the hot end. Nimonic 75 is not a blade alloy today, but it remains a casing, ducting and mounting alloy.
Nuclear engineering
Structural and support components where thermal stability, low residual impurity content and predictable weld behaviour outweigh the need for high strength.
Boilers and thermal processing
Boiler tube supports, hangers and spacers that run hot in flue gas and must not distort or scale away between overhauls.
Automotive and diesel
Exhaust valves and valve hardware in heavy-duty and high-performance engines, where the alloy's oxidation resistance and hot hardness suit the duty cycle.
Die casting and tooling
Die casting inserts and cores that face repeated thermal shock from molten metal contact and need scale resistance rather than peak hardness.
Process and petrochemical plant
Forged flanges, tube sheets, nozzles and shell rings for reformers, crackers, preheaters and shell-and-tube exchangers in hot oxidizing service.
Valves and rotating equipment
Valve bodies, seat rings and stems for high-temperature service, plus gear blanks and spindles for hot-running drives.
13Testing, inspection and certification
Every Nimonic 75 forging ships with a documentation pack. The content is agreed in writing before production starts, so there are no surprises at the inspection gate.
- Chemical analysis. Ladle analysis on every heat; product analysis on the finished forging on request.
- Mechanical testing. Tensile, proof stress, elongation, reduction of area and hardness, taken from integral or separately forged prolongations heat treated with the parts.
- Ultrasonic testing. To ASTM E2375 or AMS 2154 for wrought nickel alloy, or to EN 10228-3 / SEP 1921 acceptance classes where the customer specification calls for them.
- Surface NDT. Liquid penetrant to ASTM E1417 or EN 10228-2. Magnetic particle testing does not apply: Nimonic 75 is non-magnetic.
- Grain size and microstructure. To ASTM E112, normally ASTM 4 or finer.
- Dimensional report. Against the drawing, with the machining allowance recorded.
- Certification. EN 10204 3.1 as standard, or 3.2 witnessed and counter-signed by TUV, BV, SGS, Lloyd's Register or your own inspector.
- Additional documentation. PED 2014/68/EU and end-user specific documentation where the application requires it.
Third-party inspectors and customer QA representatives are welcome at the works. We ship the same material under the designations Alloy 75, UNS N06075, NiCr20Ti and 2.4951 where a specification calls the grade by a different name.
Nimonic 75 is fully austenitic and non-magnetic, so MT cannot be used on it. If your drawing specifies magnetic particle inspection for a Nimonic 75 part, it has been carried over from a steel drawing. We will raise it at quotation and propose liquid penetrant to ASTM E1417 instead.
14Nimonic 75 engineering tools
Eight calculators built around this grade specifically. Everything runs in your browser; nothing is uploaded, stored or sent anywhere. Results are engineering estimates for enquiry and planning; confirm against the governing specification before release to manufacture.
T1Designation lookup: is this the same alloy?
Type any designation, trade name or material number to check whether a drawing calls for Nimonic 75 or for something else.
T2Forged weight calculator: Nimonic 75 at 8.37 g/cm³
Finished weight, plus an estimated input billet weight including machining allowance and forging losses. Use this to sanity-check a quotation before you send it.
T3Grade selector: is Nimonic 75 right for your duty?
Enter service conditions and get an honest recommendation, including the cases where a cheaper stainless or a stronger superalloy is the better answer.
T4Solution anneal soak time at 1050 °C
Soak time scales with the ruling section. This applies the working rule we use on the shop floor: about 2.5 minutes per millimetre of ruling section after the load reaches temperature, with a 30 minute floor for forgings.
T5Thermal growth: clearance at temperature
How much a Nimonic 75 dimension grows between ambient and service temperature. Essential for furnace fixture clearances, retort seals and casing fits.
T6Machining data for solution-annealed Nimonic 75
Starting parameters for carbide tooling on annealed material. Reduce speed 20 to 30 percent if the surface has a forged or heat-treat skin.
T7Forging window and reduction ratio check
Checks whether a proposed billet gives enough reduction to close porosity and refine grain, and shows the temperature window the part must be worked in.
T8RFQ writer: generate a complete enquiry
Fill in what you know. The tool writes a complete enquiry with every field we need to quote in one working day, and you can copy it or open it straight in your email client.
15How to request a Nimonic 75 quotation
Send a drawing or a dimensional sketch to sales@steelforgepieces.com. Quotations are normally returned within one working day when the following points are supplied.
- Grade and standard. Nimonic 75, Alloy 75 or UNS N06075, and which specification governs: BS HR5, AMS 5683, DIN 17742 or your own drawing.
- Product form. Ring, disc, shaft, bar, flange, sleeve, tube sheet or custom shape.
- Dimensions. OD, ID and height for rings; diameter and length for bars and shafts; plus an estimated finished weight.
- Delivery condition. As-forged, solution annealed, rough machined to allowance, or finish machined.
- Certification. EN 10204 3.1 or 3.2, and which third party if 3.2.
- NDT requirements. UT standard and acceptance class, PT requirements, and any special acceptance criteria.
- Quantity and required delivery date.
Lead time for Nimonic 75 forgings is normally 30 to 60 days depending on billet availability, size and machining scope. Nickel alloy billet is not always on the floor, so early notice on a large ring shortens the quoted lead time considerably.
16Frequently asked questions about Nimonic 75
What is Nimonic 75?
Nimonic 75 is a solid-solution-strengthened 80/20 nickel-chromium superalloy designated UNS N06075 and Werkstoff 2.4951 / 2.4630. It contains 18 to 21 percent chromium, 0.2 to 0.6 percent titanium and 0.08 to 0.15 percent carbon, with nickel as the balance. Unlike Nimonic 80A and Nimonic 90 it contains no significant aluminium and forms no gamma prime, so it cannot be age hardened. Strength comes from chromium in solid solution and from titanium-rich MC carbides that pin the grain boundaries. Jiangyin Jiangnan Metal Co., Ltd. forges Nimonic 75 into rolled rings, discs, shafts, flanges and bars at its factory in Jiangyin, Jiangsu Province, China.
What is Nimonic 75 equivalent to?
Nimonic 75 is designated UNS N06075 in the United States, Werkstoff 2.4951 and 2.4630 in Germany, HR5, HR203, HR403 and HR504 in the British Standard system, NiCr20Ti in DIN 17742 and DIN 17752, NC 20T in AFNOR, and NCF 75 in JIS. It is also sold as Alloy 75, Haynes 75 and Nicrofer 7520. Russian EI435 and Chinese GH3030 are broadly comparable Ni-20Cr-Ti grades but are not exact substitutes, so cross-check the specification limits before ordering.
What is the maximum service temperature of Nimonic 75?
For stressed load-bearing components the practical design limit is about 815 degrees Celsius, or 1500 degrees Fahrenheit. For lightly loaded and unstressed parts such as furnace fixtures, muffles, trays and baskets, the alloy resists oxidation and scaling in air up to about 1100 degrees Celsius. Below about 550 degrees Celsius, austenitic stainless steels such as 321 and 347 usually do the same job at lower cost.
Can Nimonic 75 be age hardened or heat treated to higher strength?
No. Nimonic 75 is a solid-solution alloy with no gamma prime forming elements in quantity, so it cannot be precipitation hardened. The only standard heat treatment is a solution anneal at 1050 degrees Celsius followed by air cooling, which softens the alloy and restores ductility. Nimonic 75 can be strengthened by cold working, but the effect is lost on re-annealing and on exposure to service temperature. If a design needs higher strength at temperature, specify Nimonic 80A, Nimonic 90 or Nimonic 263 instead.
What is the difference between Nimonic 75 and Nimonic 80A?
Both are 80/20 nickel-chromium alloys, but Nimonic 80A adds 1.0 to 1.8 percent aluminium and 1.8 to 2.7 percent titanium, which precipitate gamma prime Ni3(Al,Ti) during ageing. That roughly doubles room-temperature tensile strength, from about 750 MPa for Nimonic 75 to about 1000 MPa or more for aged Nimonic 80A, and greatly improves creep-rupture life. The trade-off is that Nimonic 80A costs more, needs a two-stage solution and ageing treatment, is harder to machine, and is more prone to post-weld strain-age cracking. Choose Nimonic 75 when oxidation resistance, weldability and formability matter more than strength.
Is Nimonic 75 weldable?
Yes. Nimonic 75 is one of the most readily welded superalloys because it contains no gamma prime and therefore does not suffer strain-age cracking. It is welded by gas tungsten arc, gas metal arc, manual metal arc and submerged-arc processes. Welding is preferably carried out in the solution-annealed condition. Post-weld heat treatment is not normally required unless the service corrosion conditions are severe or the part must be dimensionally stress relieved.
What is the density of Nimonic 75?
The density of Nimonic 75 is 8.37 grams per cubic centimetre, or 0.302 pounds per cubic inch. Its melting range is approximately 1340 to 1380 degrees Celsius and its modulus of elasticity at room temperature is about 206 GPa. These figures are used by Jiangyin Jiangnan Metal Co., Ltd. to calculate forged billet weight from finished drawing dimensions.
What is the correct heat treatment for Nimonic 75 forgings?
Bar and forged products are solution annealed for 30 to 60 minutes at 1050 degrees Celsius, or 1920 degrees Fahrenheit, then air cooled. Sheet and thin sections are annealed for 5 to 10 minutes at the same temperature and air cooled. Soak time is scaled to the ruling section: as a working rule, allow about 2.5 minutes per millimetre of section thickness after the load reaches temperature, with a 30 minute minimum. Furnace charts for every cycle are issued with the mill certificate.
At what temperature is Nimonic 75 forged?
Nimonic 75 is hot worked between about 1180 and 950 degrees Celsius, that is 2150 to 1740 degrees Fahrenheit. Forging must finish above 950 degrees Celsius, because below that temperature the alloy work hardens rapidly and grain-boundary cracking becomes likely. Heavy sections are reheated between passes rather than forged down cold. A total reduction ratio of at least 3 to 1 from the ingot or billet is used to close porosity and refine the grain.
What forged shapes can be made in Nimonic 75?
Jiangyin Jiangnan Metal Co., Ltd. produces Nimonic 75 as seamless rolled rings with outside diameters from 200 to 6000 mm, forged discs from 150 to 2500 mm diameter, shafts and spindles from 80 to 1200 mm diameter and up to 12 000 mm long, round bars from 20 to 800 mm diameter, forged flanges, sleeves, bushings, hollow bars, blocks, tube sheets and nozzles, in single-piece weights from 10 kg to 15 000 kg. Every part is made to customer drawing; there is no fixed catalogue.
Which standards cover Nimonic 75 forgings?
Nimonic 75 forgings are ordered to BS HR5 for bar and forgings, BS HR203, HR403 and HR504 for other product forms, AMS 5683 for bars, forgings and rings, AMS 5651 for sheet and strip, DIN 17742 and DIN 17752 for wrought nickel-chromium alloys, ISO 9723 and ISO 9725, and the AECMA prEN 2293, 2294, 2302 and 2306 to 2308 aerospace series. Note that ASTM B637 covers precipitation-hardening nickel alloys and does not apply to Nimonic 75, which is a solid-solution grade. Jiangyin Jiangnan Metal Co., Ltd. also forges to customer drawings and end-user specifications.
Who supplies Nimonic 75 open-die forgings in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China, producing Nimonic 75 forged rings, discs, shafts, flanges and bars to drawing. The works operates 1, 3, 5 and 9 tonne forging hammers, a 5 000 tonne hydraulic press and 3 metre and 6 metre seamless ring rolling mills. Enquiries go to sales@steelforgepieces.com or 0086-189-2135-9659. Jiangyin sits in the Yangtze River Delta within two hours of Shanghai port, which keeps export logistics short for heavy forgings.
What certificates are supplied with Nimonic 75 forgings?
EN 10204 3.1 mill test certificates are standard, covering ladle chemical analysis, mechanical test results, heat-treatment charts, non-destructive testing reports and dimensional records. EN 10204 3.2 certificates counter-signed by TUV, BV, SGS or Lloyd's Register are available on request. PED 2014/68/EU documentation and third-party or customer witnessed inspection at the works can be arranged before production starts.
How much does Nimonic 75 cost per kilogram?
Nimonic 75 is priced per forged piece rather than by list price, because the cost is driven by the London Metal Exchange nickel price at the time of order, the input billet weight rather than the finished weight, the section size and reduction ratio, the machining allowance, the ultrasonic acceptance class and the certification level. Nimonic 75 is normally the least expensive of the Nimonic grades because it needs no ageing treatment and no aluminium or cobalt addition. Send a drawing to sales@steelforgepieces.com for a firm quotation, normally returned within one working day.
Is there a minimum order quantity for Nimonic 75 forgings?
There is no fixed minimum order quantity and single prototype pieces are accepted. Price per piece falls with quantity because melt, tooling, set-up and furnace charges are shared across the batch. Lead time is normally 30 to 60 days depending on billet availability, size, heat-treatment route and machining scope.
17About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China, operating since 2008. We produce forged rings, seamless rolled rings, discs, shafts, flanges, bars, sleeves and bushings in carbon steel, alloy steel, tool steel, stainless steel and nickel-based superalloys, including Nimonic 75, Nimonic 80A, Nimonic 90, Inconel 718, Inconel 625, Waspaloy and the Hastelloy family. All work is made to customer drawing and certified to EN 10204 3.1 or 3.2.
- Company
- Jiangyin Jiangnan Metal Co., Ltd.
- Business
- Open-die forging, seamless ring rolling, heat treatment, machining
- Established
- 2008
- Address
- No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
- Telephone
- 0086-189-2135-9659
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
- Quality system
- ISO 9001:2015; EN 10204 3.1 and 3.2 certification
- Plant
- 1, 3, 5 and 9 t forging hammers; 5 000 t hydraulic press; 3 m and 6 m ring rolling mills
- Capability
- Diameter 80–6000 mm; length to 12 000 mm; single-piece weight 10–15 000 kg
- Export
- Worldwide, via Shanghai and Zhangjiagang ports
Data source, citation and reuse
The technical data on this page is compiled and published by Jiangyin Jiangnan Metal Co., Ltd. from mill certificates, published standards and our own shop-floor practice. Engineers, buyers, technical publishers and materials databases are welcome to quote or reproduce it with attribution. Suggested citation:
Jiangyin Jiangnan Metal Co., Ltd. (2026). Nimonic 75 Forgings: Alloy 75 / UNS N06075 Technical Datasheet. Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/Nimonic-75.html
Corrections and technical queries are welcome at sales@steelforgepieces.com.
Related nickel alloy grades we forge
- Nimonic 80A
- Nimonic 90
- Inconel 718
- Inconel 706
- Inconel 625
- Inconel 600
- Inconel 601
- Inconel 617
- Inconel 690
- Inconel 693
- Inconel 725
- Inconel X-750
- Waspaloy
- Rene 41
- Udimet 500
- Udimet 520
- Udimet 720
- Haynes 230
- Haynes 188
- Haynes 25
- Multimet N155
- Incoloy 800H
- Incoloy 800HT
- Incoloy 825
- Incoloy 901
- Incoloy 925
- Incoloy 945
- Monel 400
- Monel K-500
- Monel R-405
- Hastelloy C-276
- Hastelloy C-22
- Hastelloy X
- Hastelloy B-3
- Alloy 59
- Alloy 602
- MP35N
- MP159
- NI-SPAN-C Alloy 902
- UNS N07022
- UNS N07208
- UNS N07252
Page published 17 May 2016. Last reviewed and updated by the technical sales team, Jiangyin Jiangnan Metal Co., Ltd. Technical data reviewed against BS HR5 and AMS 5683.