Nickel-based superalloy · Open-die forgings
Inconel 718 Forgings Alloy 718 / UNS N07718 / W.Nr. 2.4668. Forged rings, flanges, discs, shafts and bars.
Data sheet for Inconel 718 forgings: composition and property tables, heat treatment cycles, the standards that apply, and the sizes we forge in Jiangyin, China.
Summary
Inconel 718 (Alloy 718, UNS N07718, W.Nr. 2.4668) is a precipitation-hardenable nickel-chromium superalloy containing 50 to 55% nickel, 17 to 21% chromium, 4.75 to 5.5% niobium plus tantalum and 2.8 to 3.3% molybdenum, with iron as the balance. Aging precipitates the γ″ (Ni3Nb) and γ′ phases, giving a minimum tensile strength of 1,275 MPa (185 ksi) and a minimum 0.2% yield strength of 1,034 MPa (150 ksi) after solution treatment and aging to ASTM B637. Service range runs from cryogenic temperatures to about 700 °C (1,300 °F).
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China, forges Inconel 718 into seamless rolled rings, flanges, discs, shafts, sleeves, tube sheets and round bars to ASTM B637, AMS 5662/5663/5664 and API 6A CRA, supplied with EN 10204 3.1 or 3.2 certificates.
- Alloy
- Inconel 718 / Alloy 718
- UNS / W.Nr.
- N07718 / 2.4668
- Type
- Precipitation-hardenable Ni-Cr superalloy
- Density
- 8.19 g/cm³ (0.296 lb/in³)
- Tensile, aged
- 1,275 MPa (185 ksi) min
- Yield 0.2%, aged
- 1,034 MPa (150 ksi) min
- Service range
- −253 °C to 700 °C
- Specifications
- ASTM B637, B564, AMS 5662/5663/5664, API 6A CRA
- Forms forged
- Rings, flanges, discs, shafts, sleeves, bars, tube sheets
- Size range
- OD 100 to 3,000 mm; 5 to 8,000 kg per piece
- Certificate
- EN 10204 3.1 or 3.2
- Supplier
- Jiangyin Jiangnan Metal Co., Ltd., Jiangsu, China
What Inconel 718 is
Inconel 718 is a nickel-chromium superalloy that takes its strength from precipitation hardening rather than from cold work or a martensitic transformation.
The strengthening comes from niobium. During aging, niobium forms fine coherent γ″ (Ni3Nb) precipitates in the nickel matrix, supported by γ′ (Ni3(Al,Ti)). Because γ″ precipitates slowly, the alloy can be welded and cooled through the aging range without strain-age cracking, unlike most γ′-strengthened superalloys.
Slow precipitation also sets the temperature limit. Above roughly 650 °C, γ″ gradually converts to the equilibrium δ phase (orthorhombic Ni3Nb), which is coarse and does not strengthen. Inconel 718 is therefore specified for continuous service to about 700 °C (1,300 °F) and not beyond. The same reaction is the reason forging finish temperature and heat treatment need close control: some δ phase at the grain boundaries helps control grain size during forging, but a large volume fraction lowers strength.
Chromium and molybdenum provide the corrosion resistance. In the aged condition Inconel 718 resists oxidation, chloride pitting and crevice corrosion, and when heat treated to API 6A CRA and NACE MR0175 it resists sulfide stress cracking in sour wells.
Inconel 718 forged products and size range
Jiangyin Jiangnan Metal Co., Ltd. produces Inconel 718 forgings to drawing, in single pieces from about 5 kg to 8,000 kg, with a minimum order of one piece including prototypes.
| Forged form | Typical size range | Common uses |
|---|---|---|
| Seamless rolled rings | OD 100 to 3,000 mm · wall 20 to 400 mm · height 20 to 600 mm | Turbine casings, bearing races, wellhead spools |
| Forged flanges | OD 100 to 2,500 mm · ASME B16.5 / B16.47 or drawing | Pressure vessels, subsea piping, exchangers |
| Discs and blanks | Dia. 100 to 1,500 mm · thickness 30 to 600 mm | Turbine discs, valve seats, blind flanges |
| Shafts and spindles | Dia. 30 to 800 mm · length to 6,000 mm | Pump and compressor shafts, valve stems |
| Round and square bars | Dia. 30 to 800 mm · length to 6,000 mm | Machining stock, fasteners, downhole tools |
| Sleeves and bushings | OD 80 to 1,200 mm · ID from 40 mm | Wear parts, hangers, liners |
| Tube sheets | Dia. to 2,500 mm · thickness to 400 mm | Shell-and-tube heat exchangers |
| Blocks, cubes and step shafts | To drawing, up to 8,000 kg | Valve bodies, manifolds, die blocks |
The ranges above cover what we run routinely. Send a drawing or a sketch with dimensions and we will confirm feasibility, forging ratio and weight before quoting.
Inconel 718 chemical composition
The limits below are those of UNS N07718 in ASTM B637. AMS 5662/5663 and API 6A CRA use the same element ranges, with tighter limits on some residuals.
| Element | Symbol | Minimum | Maximum |
|---|---|---|---|
| Nickel plus cobalt | Ni + Co | 50.00 | 55.00 |
| Chromium | Cr | 17.00 | 21.00 |
| Iron | Fe | Balance, typically 17 to 20 | |
| Niobium plus tantalum | Nb + Ta | 4.75 | 5.50 |
| Molybdenum | Mo | 2.80 | 3.30 |
| Titanium | Ti | 0.65 | 1.15 |
| Aluminum | Al | 0.20 | 0.80 |
| Cobalt | Co | – | 1.00 |
| Carbon | C | – | 0.08 |
| Manganese | Mn | – | 0.35 |
| Silicon | Si | – | 0.35 |
| Copper | Cu | – | 0.30 |
| Phosphorus | P | – | 0.015 |
| Sulfur | S | – | 0.015 |
| Boron | B | – | 0.006 |
Niobium and tantalum are reported together because they behave alike in the γ″ reaction. Boron is capped at 0.006% but still matters: it segregates to grain boundaries and improves creep-rupture life.
Mechanical properties of Inconel 718 forgings
Inconel 718 is supplied in two different strength conditions. The aerospace route (ASTM B637 and AMS) develops maximum strength; the oil and gas route (API 6A CRA with NACE) caps hardness for sour service. The two are not interchangeable.
Room temperature minimums, solution treated and aged
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength, min | 1,275 MPa | 185 ksi |
| Yield strength 0.2% offset, min | 1,034 MPa | 150 ksi |
| Elongation in 4D, min | 12% | 12% |
| Reduction of area, min | 15% | 15% |
| Hardness, min | 331 HBW | 36 HRC |
| Stress rupture at 649 °C / 690 MPa | 23 h min, elong. 4% min | 1,200 °F / 100 ksi |
Sour service condition
| Property | Requirement |
|---|---|
| Tensile strength, min | 965 MPa (140 ksi) |
| Yield strength 0.2% offset | 827 to 1,034 MPa (120 to 150 ksi) |
| Elongation, min | 20% |
| Reduction of area, min | 25% |
| Hardness, max | 40 HRC |
| Grain size | ASTM 5 or finer, no duplex structure |
| Impact testing | Charpy V-notch per API 6A; temperature and acceptance per order |
Ordering note. Material aged to full ASTM B637 strength normally exceeds 40 HRC and cannot also satisfy NACE MR0175. If the part goes into H2S service, specify API 6A CRA when you place the order. The heat treatment is different and cannot be corrected afterwards.
Typical properties at elevated temperature
| Temperature | Tensile strength | 0.2% yield strength | Elongation |
|---|---|---|---|
| 20 °C / 68 °F | 1,375 MPa | 1,160 MPa | 21% |
| 540 °C / 1,000 °F | 1,230 MPa | 1,020 MPa | 18% |
| 650 °C / 1,200 °F | 1,100 MPa | 980 MPa | 18% |
| 760 °C / 1,400 °F | 760 MPa | 740 MPa | 25% |
Typical values for guidance, not guaranteed minimums. Elevated-temperature acceptance values are agreed on the order and verified on the actual heat.
Physical properties of Inconel 718
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.19 g/cm³ | 0.296 lb/in³ |
| Melting range | 1,260 to 1,336 °C | 2,300 to 2,437 °F |
| Modulus of elasticity at 20 °C | 200 GPa | 29.0 × 106 psi |
| Mean thermal expansion, 20 to 100 °C | 13.0 µm/m·°C | 7.2 µin/in·°F |
| Thermal conductivity at 20 °C | 11.4 W/m·K | 79 Btu·in/h·ft²·°F |
| Specific heat at 20 °C | 435 J/kg·K | 0.104 Btu/lb·°F |
| Electrical resistivity at 20 °C | 1.25 µΩ·m | 125 µΩ·cm |
| Curie temperature | about −112 °C | about −170 °F |
| Magnetic permeability at 21 °C, 200 Oe | 1.0011 | Non-magnetic |
Heat treatment of Inconel 718 forgings
Two heat treatment routes are in general use: the ASTM B637 and AMS 5663 cycle for maximum strength, and the higher solution temperature AMS 5664 cycle when creep-rupture life and notch ductility matter more than yield strength.
Route A: ASTM B637 / AMS 5663, maximum strength
- Solution anneal924 to 1,010 °C (1,700 to 1,850 °F), hold 30 min minimum, cool at air-cool rate or faster.
- First age718 ± 14 °C (1,325 ± 25 °F), hold 8 hours.
- Furnace coolCool in furnace to 621 ± 14 °C (1,150 ± 25 °F) at about 56 °C per hour.
- Second age and air coolHold until total precipitation time reaches 18 hours, then air cool.
Route B: AMS 5664, high solution temperature
- Solution anneal1,021 to 1,052 °C (1,870 to 1,925 °F), hold 1 hour, air cool. Dissolves δ phase and coarsens grain.
- First age760 °C (1,400 °F), hold 10 hours.
- Furnace coolCool to 649 °C (1,200 °F).
- Second age and air coolHold until total time reaches 20 hours, then air cool.
Route A gives higher room-temperature yield and tensile strength and is the default for oil-field and general engineering parts. Route B gives better stress-rupture life and notch ductility above 650 °C and is normal for rotating gas turbine hardware. For sour service, API 6A CRA prescribes its own solution and aging cycle designed to hold hardness at or below 40 HRC.
Standards, specifications and equivalent grades
| Designation | System or country | Notes |
|---|---|---|
| Inconel 718 | Trade name | Registered trademark of Special Metals Corporation |
| Alloy 718 / 718 | Generic industry | Common on drawings and purchase orders |
| UNS N07718 | USA, UNS | The designation to state on orders |
| W.Nr. 2.4668 | Germany | Material number |
| NiCr19Fe19Nb5Mo3 | DIN / EN | Chemical name form |
| GH4169 (GH169) | China, GB/T 14992 | Chinese equivalent grade |
| NCF 718 | Japan, JIS | Bar and forging grade |
| NC19FeNb | France, AFNOR | Chemical name form |
| Specification | Scope |
|---|---|
| ASTM B637 / ASME SB-637 | Precipitation-hardening nickel alloy bars, forgings and forging stock for high-temperature service |
| ASTM B564 / ASME SB-564 | Nickel alloy forgings: flanges, fittings, valves and parts |
| AMS 5662 | Bars, forgings and rings, solution heat treated, precipitation hardenable |
| AMS 5663 | Bars, forgings and rings, solution heat treated and precipitation heat treated |
| AMS 5664 | Bars, forgings and rings, high solution temperature, precipitation heat treated |
| API 6A / API 6A CRA | Wellhead and Christmas tree equipment, corrosion-resistant alloy requirements |
| NACE MR0175 / ISO 15156-3 | Materials for H2S-containing oil and gas production |
| DIN 17742 / DIN 17752 | German nickel alloy wrought product standards |
| EN 10204 3.1 / 3.2 | Type of inspection document supplied with the forging |
Forging route for Inconel 718
With a nickel superalloy, melting practice and finish forging temperature set the properties long before heat treatment does. Every Inconel 718 forging follows the same eight stages.
- Melting practiceBillet procured double melted (VIM + ESR or VIM + VAR), or triple melted (VIM + ESR + VAR) for aerospace and critical rotating parts.
- Billet inspectionIncoming chemistry verified by spectrometer, billet ultrasonically inspected before cutting.
- HeatingFurnace soak at 1,050 to 1,120 °C with controlled soak time to avoid incipient melting and grain coarsening.
- Open-die forging or ring rollingTotal forging ratio 3:1 minimum, 4:1 or more for critical parts. Finish temperature held above about 950 °C to control δ phase and grain size.
- Heat treatmentSolution anneal plus double age to ASTM B637, AMS 5663/5664 or API 6A CRA, in furnaces with calibrated and recorded temperature uniformity.
- Rough or proof machiningMachined to your allowance so that test locations and ultrasonic surfaces represent the finished part.
- Testing and NDTChemistry, tensile, hardness, grain size, ultrasonic and liquid penetrant examination against the ordered acceptance class.
- Certification and packingEN 10204 3.1 or 3.2 certificate, hard stamping or vibro-marking of heat number, seaworthy packing for export.
Where Inconel 718 forgings are used
Inconel 718 is specified when high strength has to hold up under heat, pressure and a corrosive medium at once. Oil and gas wellhead equipment and gas turbine rotating hardware account for most of the volume.
Oil, gas and subsea
Wellhead and Christmas tree bodies, tubing and casing hangers, valve bodies, bonnets, stems and seats, subsea connectors, downhole tools and packers to API 6A, API 17D and NACE MR0175.
Aerospace and gas turbine
Compressor and turbine discs, seal rings, casings, shafts, spacers, blade retainers and high-temperature fasteners. This is the largest volume application for the alloy.
Power generation
Land-based gas turbine rings and discs, steam turbine bolting, and nuclear plant components where strength and radiation resistance are both required.
Chemical and petrochemical
Pump shafts and plungers, heat exchanger tube sheets, forged flanges and nozzles for columns, towers, reactors and pressure vessels in aggressive media.
Cryogenic and space
Liquid oxygen and liquid hydrogen tankage components, rocket engine turbopump parts and fasteners that keep toughness down to −253 °C.
Heavy and process machinery
Forged rolls, wheels, manifolds, crankshafts, eccentric shafts and gear blanks for mills, mixers and compressors running hot.
Machining, welding and forming
Inconel 718 machines slowly and work hardens fast. Standard practice is to rough machine in the solution annealed condition and finish machine after aging.
Thermal conductivity of 11.4 W/m·K is about one third that of carbon steel, so heat stays at the cutting edge instead of leaving in the chip. Use rigid setups, sharp positive-rake carbide or ceramic tooling, a constant heavy feed, reduced surface speed and high-pressure coolant. Do not let the tool dwell in the cut: the work-hardened layer that forms causes rapid tool wear on the next pass. Machinability is broadly comparable to hardened stainless grades such as 410 and 17-4PH, but at higher strength.
Welding is one of the alloy's advantages. Because γ″ precipitation is sluggish, Inconel 718 resists strain-age cracking during post-weld heat treatment. GTAW and electron beam welding are the normal processes, using matching AMS 5832 / ERNiFeCr-2 filler, followed by a full solution and age cycle to restore properties across the weld.
Hot forming should be done between about 1,120 °C and 950 °C. Cold forming is possible in the annealed condition, but the alloy work hardens rapidly and intermediate anneals are usually needed.
Inconel 718 forged ring weight calculator
The weight of a rectangular-section forged ring is W = π/4 × (OD² − ID²) × H × ρ, using a density ρ of 8.19 g/cm³ for Inconel 718.
W (kg) = π ÷ 4 × (OD² − ID²) × H × 8.19 ÷ 1,000,000. Dimensions in mm.
Finished weight only. Add forging and machining allowance, typically 15 to 30% depending on tolerance class, to get the required rough weight.
Testing, inspection and certificates
Every Inconel 718 forging leaves our factory with an EN 10204 3.1 mill certificate as standard, or an EN 10204 3.2 certificate countersigned by SGS, BV, TÜV, DNV or Lloyd's Register when the order calls for third-party witness.
| Test | Method | Standard or optional |
|---|---|---|
| Chemical analysis | Spectrometer, product analysis on the heat | Standard |
| Tensile test at room temperature | ASTM E8 / ASTM A370 | Standard |
| Hardness | ASTM E18 (HRC) or ASTM E10 (HBW) | Standard |
| Grain size | ASTM E112, duplex check to ASTM E1181 | Standard for API 6A |
| Ultrasonic testing | ASTM E2375 or AMS-STD-2154 | Standard |
| Liquid penetrant testing | ASTM E1417 / ASME BPVC Section V | Standard |
| Elevated temperature tensile | ASTM E21 | On request |
| Stress rupture | ASTM E139 | On request |
| Charpy V-notch impact | ASTM E23, including low temperature | On request |
| Corrosion and sour service qualification | NACE TM0177, ASTM G48 | On request |
| Dimensional and PMI report | Positive material identification | On request |
Frequently asked questions about Inconel 718
What is Inconel 718 used for?
Inconel 718 is used where high strength has to hold up under heat, pressure and corrosion together. Typical forged parts are gas turbine discs, seal rings, casings and shafts; rocket engine components; oil and gas wellhead and Christmas tree parts, hangers, valve bodies, stems and downhole tools to API 6A and API 17D; heat exchanger tube sheets and pump shafts in chemical plants; and cryogenic tankage components down to −253 °C.
What is the maximum service temperature of Inconel 718?
About 700 °C (1,300 °F) for continuous service. Above roughly 650 °C the strengthening γ″ phase gradually transforms to δ phase during long exposure, so strength and creep resistance fall away. At the cold end the alloy keeps good toughness down to cryogenic temperatures near −253 °C, which is why it is used in liquid hydrogen systems.
Is Inconel 718 magnetic?
No, it is essentially non-magnetic at room temperature. Its Curie temperature is about −112 °C and the magnetic permeability is roughly 1.0011 at 21 °C in a 200 oersted field, so it behaves as a non-magnetic material in normal service.
What is the difference between Inconel 718 and Inconel 625?
Inconel 718 is precipitation hardened by niobium-bearing γ″ and γ′ phases and reaches about 1,275 MPa tensile and 1,034 MPa yield after aging. Inconel 625 is a solid-solution alloy at roughly 830 MPa tensile, with better general corrosion resistance and easier weldability in the as-supplied condition. Specify 718 for strength and 625 for corrosion resistance.
Which standard should I order Inconel 718 forgings to?
For aerospace, gas turbine and general high-strength use, order to ASTM B637 or AMS 5662 / 5663 / 5664. For oil and gas wellhead and sour service equipment, order to API 6A CRA together with NACE MR0175 / ISO 15156-3, which uses a different heat treatment to keep hardness at or below 40 HRC. State the specification and the required minimum yield strength on the purchase order, because the two routes are not interchangeable.
Can Inconel 718 forgings be used in sour service with H2S?
Yes, when supplied to API 6A CRA and NACE MR0175 / ISO 15156-3. That route requires a controlled solution and aging cycle, maximum hardness of 40 HRC, grain size of ASTM 5 or finer and freedom from deleterious phases. Material aged to full ASTM B637 strength is normally harder than the NACE limit, so the sour-service condition has to be specified when the order is placed.
What size Inconel 718 forged rings can you produce?
Jiangyin Jiangnan Metal Co., Ltd. produces Inconel 718 seamless rolled rings from about 100 mm to 3,000 mm outside diameter, discs and blanks up to about 1,500 mm diameter, shafts and bars from 30 mm to 800 mm diameter, and single pieces from about 5 kg to 8,000 kg. Send a drawing to sales@steelforgepieces.com and we will confirm against current capacity.
How is the weight of an Inconel 718 forged ring calculated?
Use W = π/4 × (OD² − ID²) × H × ρ with ρ = 8.19 g/cm³. For a ring of 600 mm OD, 400 mm ID and 200 mm height the finished weight is about 257 kg, before forging and machining allowance. The calculator above does the arithmetic.
Who is a reliable Inconel 718 forging manufacturer in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing Inconel 718 (UNS N07718) forged rings, flanges, discs, shafts, sleeves and bars to ASTM B637, AMS 5662/5663/5664 and API 6A CRA, with EN 10204 3.1 or 3.2 certification and a minimum order of one piece. Contact +86-189-2135-9659 or sales@steelforgepieces.com for a quotation.
What certificates and testing are supplied?
An EN 10204 3.1 mill certificate is standard; EN 10204 3.2 with third-party countersignature is available. Standard testing covers chemical analysis, room-temperature tensile, hardness, grain size to ASTM E112, ultrasonic testing to ASTM E2375 or AMS-STD-2154 and liquid penetrant testing to ASTM E1417. Stress rupture, impact and corrosion testing are added on request.
What is the lead time and minimum order quantity?
Minimum order is one piece, including single prototype forgings. Typical lead time is 15 to 45 days depending on size, heat treatment condition and billet availability. We confirm the current lead time when we quote your drawing.
Is Inconel 718 difficult to machine?
Yes. It work hardens rapidly and its low thermal conductivity concentrates heat at the cutting edge. Use rigid setups, positive-rake carbide or ceramic tooling, heavy constant feed, reduced surface speed and generous coolant, and do not dwell in the cut. Rough machining is much easier in the solution annealed condition before aging, which is one reason many buyers order proof-machined forgings in the annealed condition and age them afterwards.
Related nickel alloy forgings we produce
If Inconel 718 is not the right fit, these grades cover neighboring requirements: higher corrosion resistance, higher temperature capability, or lower cost.
- Inconel 625
- Inconel 706
- Inconel X-750
- Inconel 600
- Inconel 601
- Inconel 617
- Inconel 690
- Inconel 725
- Waspaloy
- Incoloy 925
- Incoloy 825
- Incoloy 800H
- Hastelloy C-276
- Monel K-500
- Nimonic 80A
- Nimonic 263
- Rene 41
- MP35N
We forge the same shapes in 17-4PH, 15-5PH and PH13-8Mo stainless steels, and produce seamless rolled rings and forged rings across our full grade range.
Data sources and citation
Jiangyin Jiangnan Metal Co., Ltd. (2026). Inconel 718 forgings: Alloy 718 (UNS N07718) technical data and supply. https://www.steelforgepieces.com/Nickel-Alloy/Inconel-718.html
Property data on this page is compiled from ASTM B637, AMS 5662/5663/5664, API 6A CRA and published producer data sheets. Values marked typical are for guidance and are not guaranteed minimums. Guaranteed values are those stated on the EN 10204 certificate issued with your order.