Seamless rolled rings
Ring-rolled from upset and punched preforms. The most efficient route for large-diameter Alloy 718.
- OD
- 200 - 3,000 mm
- Height
- 50 - 800 mm
- Wall
- 30 - 400 mm
§1 · Grade description
What is Alloy 718, and what is it used for?
Alloy 718 is the most widely used nickel superalloy in the world and accounts for roughly a third of all superalloy production by tonnage. After solution treatment and double ageing a forged section reaches 1,276 MPa tensile and 1,034 MPa yield while still elongating 12 % or more, and it holds that strength to about 650 °C. Above roughly 700 °C the γ″ precipitate coarsens and converts to the incoherent orthorhombic δ phase, and the alloy loses its advantage.
Why designers specify it
- It welds. γ″ precipitation is slow, so the alloy can be welded in the solution-treated condition and aged afterwards without the strain-age cracking seen in γ′-strengthened alloys such as Waspaloy and René 41.
- It works cold as well as hot. Ductility and toughness are retained down to liquid-hydrogen temperature (-253 °C), which puts it in rocket turbopumps and LNG hardware.
- It is accepted for sour service. UNS N07718 is listed in NACE MR0175 / ISO 15156-3 when produced and heat treated to the limits of the standard, normally the API 6A718 condition at 40 HRC maximum.
- Heavy sections respond evenly. Hardenability is not diffusion-limited as it is in steels, so thick wellhead bodies and turbine discs age through the section without a soft core.
Naming note. Inconel® is a registered trademark of Special Metals Corporation;
Haynes®, Pyromet®, Udimet® and Nicrofer®
belong to their respective owners. Jiangyin Jiangnan Metal Co., Ltd. supplies this grade under the generic
designation Alloy 718 / UNS N07718 / W.Nr. 2.4668 and does not represent its products as those
of any trademark holder. Trade names are listed here only so buyers can cross-reference specifications.
§2 · Chemical composition
Alloy 718 chemical composition (% by mass)
Alloy 718 to ASTM B637 / AMS 5662 contains 50.00-55.00 % Ni (+Co), 17.00-21.00 % Cr, 4.75-5.50 % Nb (+Ta), 2.80-3.30 % Mo, 0.65-1.15 % Ti and 0.20-0.80 % Al, with iron as the balance (typically 17-20 %). Carbon is limited to 0.08 % maximum. API 6A718 narrows the Nb, Ti and Al windows and tightens carbon, sulphur, copper and trace elements to control δ-phase and Laves-phase formation in heavy oilfield sections.
| Element | ASTM B637 / AMS 5662 | API 6A718 (oilfield) | Role in the alloy |
|---|---|---|---|
| Nickel (Ni + Co) | 50.00 - 55.00 | 50.00 - 55.00 | Austenitic matrix; γ″ and γ′ former |
| Chromium (Cr) | 17.00 - 21.00 | 17.00 - 21.00 | Oxidation and corrosion resistance |
| Iron (Fe) | Balance (≈ 17 - 20) | Balance | Cost and density reduction; γ″ stabiliser |
| Niobium (Nb + Ta) | 4.75 - 5.50 | 4.87 - 5.20 | Primary γ″ (Ni₃Nb) strengthener |
| Molybdenum (Mo) | 2.80 - 3.30 | 2.80 - 3.30 | Solid-solution strength; pitting resistance |
| Titanium (Ti) | 0.65 - 1.15 | 0.80 - 1.15 | γ′ former; carbide/nitride former |
| Aluminium (Al) | 0.20 - 0.80 | 0.40 - 0.60 | γ′ former; deoxidiser |
| Cobalt (Co) | 1.00 | 1.00 | Residual; counted within Ni range |
| Carbon (C) | 0.08 | 0.045 | MC carbides; restricted for toughness |
| Manganese (Mn) | 0.35 | 0.35 | Residual from melting |
| Silicon (Si) | 0.35 | 0.35 | Residual deoxidiser |
| Copper (Cu) | 0.30 | 0.23 | Residual; restricted for sour service |
| Phosphorus (P) | 0.015 | 0.015 | Grain-boundary embrittlement control |
| Sulphur (S) | 0.015 | 0.010 | Hot-workability; restricted for cleanliness |
| Boron (B) | 0.006 | 0.006 | Grain-boundary cohesion; creep life |
Order against the current edition of the specification. API 6A718 also restricts lead, bismuth,
selenium and magnesium to trace levels that are not shown above, and those limits are confirmed per order.
Where a customer specification is tighter than the governing standard, the customer specification is what
we work to.
§3 · Mechanical properties
Alloy 718 mechanical properties by heat-treated condition
In the solution-treated and aged (STA) condition to AMS 5662 / ASTM B637, Alloy 718 forgings meet 1,276 MPa (185 ksi) minimum tensile strength, 1,034 MPa (150 ksi) minimum 0.2 % proof strength, 12 % minimum elongation, 15 % minimum reduction of area and 331 HB minimum hardness. In the API 6A718 condition the yield strength is held to 827-1,034 MPa (120-150 ksi) with 20 % elongation and 40 HRC maximum, trading peak strength for the toughness and hardness limits required by NACE MR0175 / ISO 15156 sour service.
| Condition / specification | Tensile strength Rm | 0.2 % proof Rp0.2 | Elongation A | Reduction of area Z | Hardness |
|---|---|---|---|---|---|
| Solution treated + aged AMS 5662 / 5663 · ASTM B637 (954 °C solution) |
≥ 1,276 MPa ≥ 185 ksi |
≥ 1,034 MPa ≥ 150 ksi |
≥ 12 % | ≥ 15 % | ≥ 331 HB ≈ 36 HRC |
| Solution treated + aged AMS 5664 (1,038 °C solution, creep-rupture) |
≥ 1,241 MPa ≥ 180 ksi |
≥ 1,034 MPa ≥ 150 ksi |
≥ 12 % | ≥ 15 % | ≥ 331 HB |
| Oilfield condition API 6A718 / ASTM A1014 · NACE MR0175 |
≥ 965 MPa ≥ 140 ksi |
827 - 1,034 MPa 120 - 150 ksi |
≥ 20 % | ≥ 25 % | ≤ 40 HRC |
| Solution annealed (unaged) typical as-supplied for further forming or welding |
≈ 965 - 1,100 MPa | ≈ 550 - 760 MPa | ≈ 35 - 45 % | ≈ 45 - 55 % | ≤ 30 HRC |
Elevated-temperature tensile properties (STA, typical)
| Test temperature | Tensile strength | 0.2 % proof strength | Elongation |
|---|---|---|---|
| -196 °C (-320 °F) | ≈ 1,570 MPa | ≈ 1,250 MPa | ≈ 20 % |
| 21 °C (70 °F) | ≈ 1,400 MPa | ≈ 1,170 MPa | ≈ 20 % |
| 538 °C (1,000 °F) | ≈ 1,200 MPa | ≈ 1,030 MPa | ≈ 18 % |
| 649 °C (1,200 °F) | ≈ 1,100 MPa | ≈ 980 MPa | ≈ 19 % |
| 704 °C (1,300 °F) | ≈ 950 MPa | ≈ 860 MPa | ≈ 22 % |
| 760 °C (1,400 °F) | ≈ 720 MPa | ≈ 640 MPa | ≈ 25 % |
Stress-rupture requirement
AMS 5662 requires a stress-rupture life of at least 23 hours at 649 °C (1,200 °F) under 690 MPa (100 ksi) with at least 4 % elongation. The higher 1,038 °C solution of AMS 5664 coarsens the grain and extends rupture life, at the cost of some room-temperature tensile strength. It is the usual choice for hot-section turbine components.
§4 · Physical properties
Alloy 718 physical and thermal properties
Alloy 718 has a density of 8.19 g/cm³ (0.296 lb/in³), a melting range of 1,260-1,336 °C (2,300-2,437 °F), a room-temperature elastic modulus of about 200 GPa (29.0 × 10⁶ psi) and a mean coefficient of thermal expansion of 13.0 µm/m·°C between 20 and 100 °C. It is non-magnetic at room temperature, with a Curie temperature below -112 °C and relative permeability of about 1.001.
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.19 g/cm³ | 0.296 lb/in³ |
| Melting range | 1,260 - 1,336 °C | 2,300 - 2,437 °F |
| Modulus of elasticity, 20 °C | 200 GPa | 29.0 × 10⁶ psi |
| Modulus of elasticity, 649 °C | ≈ 163 GPa | ≈ 23.6 × 10⁶ psi |
| Shear modulus, 20 °C | ≈ 77.2 GPa | ≈ 11.2 × 10⁶ psi |
| Poisson's ratio | 0.29 | 0.29 |
| Specific heat, 20 °C | 435 J/kg·K | 0.104 Btu/lb·°F |
| Thermal conductivity, 20 °C | 11.4 W/m·K | 79 Btu·in/ft²·h·°F |
| Mean CTE, 20 - 100 °C | 13.0 µm/m·°C | 7.2 µin/in·°F |
| Mean CTE, 20 - 649 °C | ≈ 14.7 µm/m·°C | ≈ 8.2 µin/in·°F |
| Electrical resistivity, 20 °C | 1.25 µΩ·m | 125 µΩ·cm |
| Curie temperature | < -112 °C | < -170 °F |
| Relative permeability, 20 °C | ≈ 1.001 | ≈ 1.001 |
§5 · Heat treatment
Heat treatment of Alloy 718 forgings
The standard aerospace cycle (AMS 5662) is: solution treat at 927 to 1,010 °C, typically 954 °C (1,750 °F), for about 1 hour and air cool; then double age at 718 °C (1,325 °F) for 8 hours, furnace cool at approximately 55 °C/h (100 °F/h) to 621 °C (1,150 °F), hold to a total ageing time of about 18 hours, then air cool. AMS 5664 substitutes a 1,038 °C (1,900 °F) solution for improved creep-rupture life. API 6A718 requires solution annealing at 1,021-1,052 °C followed by ageing at 774-802 °C with furnace cooling to 649-663 °C, an 18-hour total cycle that limits δ phase and holds hardness to 40 HRC maximum for sour service.
| Specification | Solution treatment | Ageing | Selected for |
|---|---|---|---|
| AMS 5662 / 5663 ASTM B637 Type 1 |
927 - 1,010 °C (typ. 954 °C), 1 h, air cool | 718 °C / 8 h → furnace cool 55 °C/h → 621 °C / hold to 18 h total → air cool | Maximum room- and mid-temperature tensile and fatigue strength; fine grain |
| AMS 5664 ASTM B637 Type 2 |
1,038 °C ± 14 °C, 1 - 2.5 h, air cool | Same double-age cycle as above | Creep and stress-rupture life in hot-section turbine parts |
| API 6A718 ASTM A1014 |
1,021 - 1,052 °C (1,870 - 1,925 °F), 1 - 2.5 h, quench | 774 - 802 °C / 6 - 8 h → furnace cool → 649 - 663 °C / hold to 18 h total → air cool | Sour service; controlled yield window and ≤ 40 HRC per NACE MR0175 |
| Solution annealed only | 954 - 1,010 °C, air cool or water quench | None. Aged after machining or welding | Parts to be cold formed, machined or welded before final ageing |
Note on δ phase. Orthorhombic δ (Ni₃Nb) precipitates between roughly 860 and 1,010 °C. A
controlled amount pins grain boundaries during sub-solvus forging and helps hold grain size; too much
consumes the niobium that would otherwise form γ″ and drops both strength and notch ductility. Give us the
governing specification and the intended service temperature and we will confirm the cycle in writing before
production starts.
§6 · Melting route and forging practice
How Alloy 718 forgings are melted and forged
Alloy 718 billet is supplied in three routes. VIM + VAR (vacuum induction melting followed by vacuum arc remelting) is the normal requirement for API 6A718 wellhead equipment and most aerospace work. VIM + ESR + VAR triple melt is specified for rotating aerospace components where the lowest possible inclusion content is required. EAF + AOD/VOD + ESR is an economical route acceptable for general industrial service. Forging is carried out between about 1,120 °C and a finishing temperature above 954 °C, with sub-solvus finishing used to hold grain size to ASTM No. 5 or finer.
Melting routes compared
| Route | Typical requirement | Cleanliness | Relative cost |
|---|---|---|---|
| EAF + AOD/VOD + ESR | General industrial, pumps, fasteners, non-critical process hardware | Commercial | Base |
| VIM + VAR (double melt) | API 6A718 wellhead and subsea, most static aerospace, land-based gas turbine | Premium | +30 - 60 % |
| VIM + ESR + VAR (triple melt) | Rotating aerospace discs and shafts, AMS 2280 fracture-critical parts | Premium plus | +70 - 120 % |
Forging parameters
- Heating. Charge into a furnace at or below 815 °C and heat to 1,010-1,120 °C. Do not exceed about 1,120 °C, since incipient melting of Laves phase begins near 1,150 °C.
- Finishing temperature. Finish above 954 °C. Sub-solvus finishing between 954 and 1,010 °C, with at least 20 % reduction in the final passes, produces the fine, uniform structure required by API 6A718 and AMS specifications.
- Reduction ratio. A minimum 3:1 forging reduction from billet is normal practice; heavy wellhead and disc sections are frequently upset and drawn repeatedly to break down as-cast structure.
- Grain size. ASTM No. 5 or finer to ASTM E112 is the usual acceptance level; ASTM 6-8 is achievable on controlled sub-solvus schedules.
- Reheating. The hot-working window is narrow and the alloy work-hardens quickly, so reheats are planned into the schedule rather than pushing a heat below its finishing temperature.
§7 · Product forms and size range
Alloy 718 forged product forms we supply
Jiangyin Jiangnan Metal Co., Ltd. produces Alloy 718 as seamless rolled rings, forged discs and blanks, shafts and spindles, round bars, flanges, sleeves and bushings, hollow bars and tube sheets, and rectangular blocks, supplied rough-machined or in the as-forged, heat-treated condition with machining allowance, from 5 kg to 8,000 kg per piece.
Forged discs & blanks
Upset discs for turbine wheels, valve closures, flange blanks and hub forgings.
- OD
- 100 - 2,000 mm
- Thickness
- 20 - 600 mm
Shafts & spindles
Stepped and plain shafts drawn on the press, ultrasonically tested full length.
- Dia
- 80 - 1,200 mm
- Length
- up to 8,000 mm
Round bars
Forged and peeled bar for machined valve stems, fasteners and downhole tools.
- Dia
- 50 - 800 mm
- Length
- up to 6,000 mm
Flanges
Weld-neck, blind, slip-on and special flanges to ASME B16.5, B16.47 or drawing.
- OD
- 50 - 2,500 mm
Sleeves & bushings
Bored hollow forgings for pump wear parts, hangers and subsea connectors.
- OD
- 100 - 1,500 mm
- Wall
- from 25 mm
Blocks & rectangles
Forged rectangular sections for machined valve bodies and manifold blocks.
- Section
- up to 800 × 800 mm
- Length
- up to 3,000 mm
Tube sheets & hollow bars
Drilled tube sheets and trepanned hollows for heat exchangers and pressure vessels.
- OD
- up to 2,500 mm
Maximum single-piece weight is 8,000 kg for Alloy 718. The sizes above are the working envelope for
open-die and ring-rolled work. Parts outside it are quoted case by case. Send the drawing and we will confirm
feasibility, forging weight and machining allowance before quoting.
§8 · Standards and equivalents
Alloy 718 specifications, standards and international equivalents
Alloy 718 forgings are ordered against ASTM B637 (bars, forgings and forging stock for high-temperature service), ASME SB-637 for pressure-vessel use, AMS 5662/5663/5664 for aerospace, and API 6A718 / ASTM A1014 for API 6A and API 17D oilfield equipment. The grade is designated UNS N07718 in the United States, W.Nr. 2.4668 / NiCr19Fe19Nb5Mo3 in Europe, NCF 718 in Japan and GH4169 in China.
| Standard | Scope | Applies to |
|---|---|---|
| ASTM B637 | Precipitation-hardening nickel alloy bars, forgings and forging stock for high-temperature service | General and industrial forgings |
| ASME SB-637 | ASME Boiler & Pressure Vessel Code adoption of ASTM B637 | Coded pressure equipment |
| AMS 5662 / 5663 | Bars, forgings and rings, 954 °C solution + precipitation heat treated | Aerospace structural and static parts |
| AMS 5664 | Bars, forgings and rings, 1,038 °C solution + precipitation heat treated | Creep-limited hot-section parts |
| API 6A718 / ASTM A1014 | Nickel alloy 718 for oil and gas drilling and production equipment | Wellhead, subsea and valve components |
| NACE MR0175 / ISO 15156-3 | Materials for use in H₂S-containing environments | Sour-service qualification, ≤ 40 HRC |
| DIN 17752 / 17754 · EN 10269 | European bar, forging and fastener standards for 2.4668 | European projects |
| GB/T 14992 · GB/T 14994 | Chinese superalloy designation and forging standards for GH4169 | Domestic Chinese supply |
| EN 10204 | Types of inspection documents (3.1 mill certificate, 3.2 third-party countersigned) | Certification for all orders |
| System | Designation |
|---|---|
| USA (UNS) | N07718 |
| Germany (Werkstoff) | 2.4668 |
| Europe (EN chemical symbol) | NiCr19Fe19Nb5Mo3 |
| China (GB/T) | GH4169 (GH169) |
| Japan (JIS) | NCF 718 |
| France (AFNOR) | NC19FeNb |
| Common trade names | Inconel® 718 · Nicrofer® 5219 Nb · Haynes® 718 · Pyromet® 718 · Udimet® 718 · ATI 718™ |
§9 · Applications
Where Alloy 718 forgings are used
Gas turbines, both aero and industrial, take the largest share of Alloy 718 production: discs, rings, casings, seals and shafts. Oil and gas is the next largest market, where API 6A718 forgings become wellhead bodies, hangers, valve stems, subsea connectors and downhole tool housings. It is also used in cryogenic rocket turbopumps, nuclear reactor internals, high-pressure chemical process equipment and high-performance fastener stock.
Oil, gas and subsea
- Wellhead bodies, casing and tubing hangers
- Gate, ball and check valve bodies, stems and seat rings
- Subsea connectors, hubs and clamp segments
- Downhole tool housings, MWD/LWD collars, packer components
- Christmas tree components to API 6A / 17D
Aero and industrial gas turbines
- Compressor and turbine discs, spacers and seal rings
- Casings, diffusers and combustor hardware
- Shafts, spindles and stub shafts
- High-strength bolting and fastener stock
Cryogenic and aerospace propulsion
- Rocket turbopump impellers, housings and shafts
- Liquid-hydrogen and LNG valve and pump components
- Structural fittings retaining toughness to -253 °C
Chemical and process plant
- Pump shafts, sleeves and wear rings for aggressive duty
- High-pressure vessel nozzles, tube sheets and closures
- Heat-exchanger components and flanges
- Extrusion and hot-working tooling
Power and nuclear
- Land-based gas turbine rotating and static hardware
- Reactor internals, springs and fastener components
- Steam-plant high-temperature bolting
Heavy machinery and tooling
- Hot-die and extrusion tooling requiring hot hardness
- Rolls, mandrels and forming dies
- Gears and power-transmission components for hot service
§10 · Testing, inspection and certification
Testing and certification supplied with every Alloy 718 order
Every Alloy 718 forging is supplied with chemical analysis, tensile testing to ASTM E8 or ISO 6892, hardness to ASTM E18, grain size to ASTM E112 and ultrasonic testing to ASTM A388, EN 10228-3 or AMS-STD-2154 as specified. Charpy V-notch impact testing to ASTM E23 is added for API 6A718 and sour-service orders. Documentation is issued as an EN 10204 3.1 mill certificate, or EN 10204 3.2 countersigned by SGS, BV, TÜV, DNV or Lloyd's Register when the order requires it.
| Test | Method | Scope |
|---|---|---|
| Chemical analysis | Optical emission spectrometry; combustion analysis for C and S | Every heat, product analysis on request |
| Tensile | ASTM E8 / E21 · ISO 6892-1 | Every heat-treatment lot; test-block location per specification |
| Hardness | ASTM E18 (HRC) · ASTM E10 (HB) | Every piece for API 6A718 orders |
| Charpy V-notch impact | ASTM E23 · ISO 148-1 | Sour service and low-temperature orders |
| Grain size | ASTM E112 | ASTM No. 5 or finer unless otherwise specified |
| Microstructure | δ-phase and Laves-phase evaluation; ASTM E45 inclusion rating | On specification requirement |
| Ultrasonic testing | ASTM A388 · EN 10228-3 · AMS-STD-2154 · API 6A Annex M | 100 % volumetric on critical parts |
| Liquid penetrant | ASTM E1417 · ASME Section V | Machined and sealing surfaces |
| Dimensional | Against approved forging drawing | Every piece, recorded |
| Positive material identification | Portable XRF | On request; standard for API orders |
| Certification | EN 10204 3.1 or 3.2 | Issued with every shipment; heat and piece traceable |
§11 · How to order
How to order Alloy 718 forgings
Email a drawing or size list to sales@steelforgepieces.com stating the governing specification, melting route, heat-treated condition and certificate level. A quotation with unit weight, price, lead time and the proposed test plan is returned within 24 working hours. Typical lead time is 30-45 days from available billet and 50-70 days when new melt to a specific route is required.
- Send the geometry. A drawing is ideal. A rough-machined size list, or finished sizes plus your machining allowance, is enough to quote.
- State the specification. ASTM B637, AMS 5662, AMS 5663, AMS 5664 or API 6A718, plus any customer specification that overrides it.
- State the melting route and condition. VIM+VAR, VIM+ESR+VAR or EAF+AOD/VOD+ESR; solution annealed, or solution treated and aged.
- State the documentation. EN 10204 3.1 or 3.2, third-party witness requirements, and any PMI, NDT or marking requirements.
- Approve the plan. We return the forging drawing, heat-treatment cycle and inspection and test plan for approval before cutting billet.
- Production and shipment. Forging, heat treatment, machining, testing, certification and export packing. FOB Shanghai or Ningbo, CIF and DDP available.
Not sure which specification you need? Give us the service conditions: temperature, pressure, H₂S
partial pressure and the equipment standard the part belongs to. We will propose the specification, melting
route and heat treatment, then confirm it in writing on the quotation.
§12 · Frequently asked questions
Alloy 718 buyer and engineering questions
What is Alloy 718?
Alloy 718 (UNS N07718, W.Nr. 2.4668) is a precipitation-hardenable nickel-chromium superalloy containing 50-55 % nickel, 17-21 % chromium, 4.75-5.5 % niobium and 2.8-3.3 % molybdenum, with iron as the balance. It is strengthened by the γ″ phase Ni3Nb, reaches 1,276 MPa minimum tensile strength after solution treatment and ageing, and retains useful strength from cryogenic temperatures up to about 700 °C. It is the most widely used nickel superalloy in the world by tonnage.
Is Alloy 718 the same as Inconel 718?
Chemically they are the same grade. Both describe UNS N07718. Inconel® is a registered trade name of Special Metals Corporation; Alloy 718 is the generic designation for the same composition, and every reputable producer works to the same ASTM, AMS and API requirements. Jiangyin Jiangnan Metal Co., Ltd. supplies the grade as Alloy 718 / UNS N07718 / 2.4668 and certifies it to the specification named on your order.
What is the maximum service temperature of Alloy 718?
About 700 °C (1,300 °F) for short-term or lightly loaded service, and about 650 °C (1,200 °F) for sustained load-bearing duty. Above this range the strengthening γ″ phase coarsens and transforms to δ, and strength falls away quickly. For hot-section parts operating above 700 °C, Waspaloy, Alloy 706 or a cast nickel alloy is the appropriate choice.
What are the mechanical properties of Alloy 718 in the solution treated and aged condition?
To AMS 5662 or ASTM B637 the specified minima are 1,276 MPa (185 ksi) tensile strength, 1,034 MPa (150 ksi) 0.2 % proof strength, 12 % elongation, 15 % reduction of area and 331 HB hardness. Under API 6A718 the yield strength is instead controlled to a 827-1,034 MPa (120-150 ksi) window with 20 % elongation, 25 % reduction of area and 40 HRC maximum hardness for sour service.
What heat treatment is used for Alloy 718 forgings?
The standard AMS 5662 cycle is: solution treat at 927-1,010 °C (typically 954 °C) for about 1 hour and air cool, then double age at 718 °C for 8 hours, furnace cool at about 55 °C/h to 621 °C, hold to a total ageing time of about 18 hours and air cool. AMS 5664 substitutes a 1,038 °C solution for better creep-rupture life. API 6A718 requires solution annealing at 1,021-1,052 °C and ageing at 774-802 °C to hold hardness at 40 HRC maximum.
Which melting route should be specified for Alloy 718 forgings?
VIM + VAR double melt is the normal requirement for API 6A718 wellhead equipment and most aerospace work. VIM + ESR + VAR triple melt is used for rotating aerospace components needing the lowest inclusion content. EAF + AOD/VOD + ESR is an economical route acceptable for general industrial service. Jiangyin Jiangnan Metal sources billet to whichever route your specification requires.
How does Alloy 718 compare with Inconel 625?
Alloy 718 is precipitation hardened and roughly twice as strong: 1,276 MPa minimum tensile against about 827 MPa for solution-annealed Alloy 625. For load-bearing parts such as hangers, discs, shafts and valve stems, 718 is the usual choice. Alloy 625 is a solid-solution alloy with better general and seawater corrosion resistance and better weld-overlay behaviour, so it is preferred where corrosion rather than mechanical load governs the design. See our Inconel 625 forgings page.
Can Alloy 718 be welded?
Yes, and it is one of the main reasons the grade gets specified. γ″ precipitation is slow, so the alloy can be welded in the solution-treated condition without the strain-age cracking common to γ′-strengthened superalloys. GTAW and electron-beam welding are the usual processes, with ERNiFeCr-2 (AMS 5832) filler. A full solution treatment and double age after welding restores properties across the joint.
Is Alloy 718 magnetic?
No. It is austenitic and non-magnetic at room temperature, with relative permeability around 1.001 and a Curie temperature below -112 °C. That matters for MWD and LWD drill-collar housings, where directional survey tools need the housing to be magnetically transparent.
Is Alloy 718 approved for sour service under NACE MR0175 / ISO 15156?
Yes. UNS N07718 is listed in NACE MR0175 / ISO 15156-3 when produced and heat treated within the limits of the standard, in practice the API 6A718 condition with hardness at 40 HRC maximum and a controlled 120 to 150 ksi yield window. The permitted H₂S partial pressure, chloride level and temperature depend on the material class, so confirm the intended well conditions against the standard before ordering.
Why is Alloy 718 so difficult to machine?
Aged Alloy 718 has high hot hardness, low thermal conductivity (11.4 W/m·K, roughly a quarter of steel) and severe work-hardening, so heat concentrates at the cutting edge. Common practice is to rough machine in the solution-annealed condition and finish after ageing, using rigid setups, positive-rake carbide or ceramic inserts, low surface speeds with heavy feeds, and high-pressure flood coolant. A tool that dwells or rubs work-hardens the surface immediately.
What is the maximum size of Alloy 718 forging you can supply?
Jiangyin Jiangnan Metal Co., Ltd. supplies Alloy 718 open-die forgings from about 5 kg to 8,000 kg single-piece weight: seamless rolled rings to 3,000 mm outside diameter, discs to 2,000 mm, round bars 50-800 mm diameter and shafts up to about 8,000 mm long. Parts outside that envelope are quoted case by case. Send the drawing and we will confirm feasibility before quoting.
What is the lead time and minimum order quantity for Alloy 718 forgings?
Quotations are returned within 24 working hours of receiving a drawing or size list. Typical production lead time is 30-45 days from available billet, and 50-70 days when new melt to a specific route must be procured. There is no fixed minimum piece count. Single prototype forgings are accepted, although for small pieces the economics depend on billet availability in the required melting route.
What testing and documentation ship with an Alloy 718 order?
Standard scope covers chemical analysis, tensile testing to ASTM E8 or ISO 6892, hardness to ASTM E18, Charpy V-notch impact to ASTM E23 where required, grain size to ASTM E112, and ultrasonic testing to ASTM A388, EN 10228-3 or AMS-STD-2154. Certificates are issued to EN 10204 3.1, or EN 10204 3.2 countersigned by a third party such as SGS, BV, TÜV, DNV or Lloyd's Register, with full heat and piece traceability.
§14 · Manufacturer
About the manufacturer, Jiangyin Jiangnan Metal Co., Ltd.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The plant produces open-die forgings and seamless rolled rings in carbon steel, alloy steel, tool steel, stainless steel and nickel-based superalloys, supplying forged rings, discs, shafts, round bars, flanges, sleeves, bushings, tube sheets and blocks from 5 kg to 8,000 kg single-piece weight to customers in the oil and gas, power generation, chemical process, marine and heavy machinery industries worldwide. Alloy 718 (UNS N07718) forgings are supplied to ASTM B637, ASME SB-637, AMS 5662/5663/5664 and API 6A718, with EN 10204 3.1 or 3.2 certification.
Company
Jiangyin Jiangnan Metal Co., Ltd.
Plant address
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone / WhatsApp
Website
Capability
Open-die forging · Ring rolling · Heat treatment · Machining
Cite this data sheet
Jiangyin Jiangnan Metal Co., Ltd. (2026). "Alloy 718 Forgings (UNS N07718 / W.Nr. 2.4668) Technical Data Sheet." Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Nickel-Alloy/ALLOY-718.html
Published 18 April 2016 · Last reviewed and revised 13 August 2026 by the technical sales department of Jiangyin Jiangnan Metal Co., Ltd. Property values are taken from the governing ASTM, AMS and API specifications and from published producer data. Values marked "typical" are for guidance only and are not guaranteed minima; the specification named on the purchase order governs in all cases.
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