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Nickel-chromium (Ni-Cr) alloy UNS N07718 EN 2.4668

Inconel 718

Inconel 718 (Alloy 718, UNS N07718) is a precipitation-hardenable nickel-chromium-iron alloy with very high yield, tensile and creep-rupture strength up to about 650 °C.

Also known asAlloy 718UNS N077182.4668NiCr19Fe19Nb5Mo3

N07718
UNS
8.19 g/cm³
Density
9
Forms

Inconel 718 at a glance

Family
Nickel Alloys · Nickel-chromium (Ni-Cr) alloy
UNS
N07718
EN / W.Nr
2.4668 · NiCr19Fe19Nb5Mo3
Density
8.19 g/cm³
Pipes
To order
Tubes
AMS 5589 / 5590
Plates
AMS 5596 / ASTM B670
Sheets
AMS 5596 / 5597
On this page 13 sections
  1. Overview
  2. Specifications
  3. Chemical composition
  4. Mechanical properties
  5. Physical properties
  6. Fabrication
  7. Available products
  8. Applications
  9. Related grades
  10. Markets
  11. Buying checklist
  12. Explore more
  13. FAQs

What is Inconel 718?

Quick answer

Definition
Inconel 718 (Alloy 718, UNS N07718) is a precipitation-hardenable nickel-chromium-iron alloy with very high yield, tensile and creep-rupture strength up to about 650 °C.
Family
Nickel-chromium (Ni-Cr) alloy
Key strength
Age-hardenable: yield strength above 1,000 MPa
Main forms
Pipes, Tubes, Plates, Sheets, Bars, Flanges
Typical uses
Aero-engine discs, shafts and casings; Oil and gas downhole tools and hangers; Wellhead and valve components (API 6A718)

Alloy 718 is strengthened by niobium-rich gamma-double-prime precipitates that form during ageing. Its slow ageing response means it can be welded and annealed without spontaneous hardening, which made it the most widely used superalloy for aero-engine discs, shafts and casings.

Outside aerospace, 718 is used for oil and gas completion tools, wellhead and valve components (API 6A718), high-strength bolting and cryogenic tankage. Most supply is bar, forgings and sheet to AMS or API specifications. Always specify the heat-treatment condition (solution-annealed, or solution-treated and aged).

Key characteristics

  • Age-hardenable: yield strength above 1,000 MPa
  • Excellent creep and fatigue strength to about 650 °C
  • Weldable without strain-age cracking
  • Mainly bar, forgings and sheet (AMS / API 6A718)

What are the specifications and equivalents of Inconel 718?

Inconel 718: specification by product form
Product formSpecification / designationProduct page
PipesTo order (AMS / customer specification)Inconel 718 pipes →
TubesAMS 5589 / 5590Inconel 718 tubes →
PlatesAMS 5596 / ASTM B670Inconel 718 plates →
SheetsAMS 5596 / 5597Inconel 718 sheets →
BarsASTM B637 / AMS 5662 / 5663 / API 6A718Inconel 718 bars →
FlangesASTM B637 forgingsInconel 718 flanges →
BoltsASTM B637 / AMS 5662Inconel 718 bolts →
NutsASTM B637Inconel 718 nuts →
WashersAMS 5596Inconel 718 washers →

UNS N07718 · EN 2.4668 (cross-reference; limits are similar but not identical) · Inconel® is a trademark of Special Metals Corporation; generic material is supplied to the specification on your order.

Standards: ASTM B637, ASTM B670.

What is the chemical composition of Inconel 718?

Inconel 718 chemical composition, % (AMS 5662 / ASTM B637)
ElementLimit (%)
Ni50.0 – 55.0
Cr17.0 – 21.0
Nb + Ta4.75 – 5.50
Mo2.80 – 3.30
Ti0.65 – 1.15
Al0.20 – 0.80
Co1.00 max
C0.08 max
FeBalance
Limits per the cited specification. Other product forms and specifications may differ slightly. Confirm against the edition named on your order.
0%10%20%30%40%50%60% Ni 50.0 – 55.0 Cr 17.0 – 21.0 Nb + Ta 4.75 – 5.50 Mo 2.80 – 3.30 Co 1.00 max
Main alloying elements of Inconel 718. Bars show the permitted range.

What are the mechanical properties of Inconel 718?

Inconel 718 mechanical properties (typical): AMS 5663 (solution-treated and aged, typical minimums)
PropertyValue
Tensile strength1,275 MPa (185 ksi)
Yield strength (0.2% offset)1,034 MPa (150 ksi)
Elongation12%
Hardness≈ 36 HRC min
Typical values for reference only. They aren't specification guarantees.

Physical properties and service temperature

Inconel 718: physical and metallurgical summary
PropertyValue
Density (typical)8.19 g/cm³ (8190 kg/m³)
MagnetismNon-magnetic.
Heat treatmentSupplied annealed or solution annealed, and age-hardened when specified.
Service temperatureHigh strength to about 650 °C; also excellent at cryogenic temperatures.

How is Inconel 718 welded and fabricated?

Weldable by TIG, MIG and SMAW with matching or over-alloyed nickel fillers. Keep surfaces clean of sulphur and low-melting contaminants.

Always follow a qualified welding procedure (for example ASME Section IX) and the filler-metal recommendations for Inconel 718. Verify incoming material by PMI and check the mill test certificate against the specification.

Which Inconel 718 products do we supply?

Inconel 718 is available in 9 product forms, from ready stock or mill-sourced to your specification, with EN 10204 3.1 mill test certificates (3.2 with third-party inspection on request).

Inconel 718 PipesTo orderSpecification & sizes
Inconel 718 pipe cross-section, NPS 6 Sch 40S Engineering drawing showing outside diameter 168.28 mm and wall thickness 7.11 mm (To order Inconel 718). Wall thickness is exaggerated for clarity. OD 168.28 mm WT 7.11 mm NPS 6SCH 40S To order Inconel 718

How it's madeSeamless pipe is pierced from a solid billet and hot-finished or cold-drawn. Welded pipe is formed from strip or plate and welded longitudinally (ERW/HFW, TIG/plasma, EFW, LSAW) or spirally (SAWH). Stainless and nickel-alloy pipe is then solution annealed and pickled. Carbon and alloy steel pipe is supplied as-rolled, normalised, or normalised and tempered according to the specification.

Specification
To order (AMS / customer specification)
Size range
NPS ⅛" to 48" and larger (DN 6 – DN 1200+), schedules 5S to XXS, single random, double random and cut lengths
Finish
Annealed & pickled, bright annealed, mill finish, black, varnished, galvanised or 3LPE / FBE coated (by material)
Ends
Plain end (PE), bevelled end (BE, ASME B16.25), threaded (NPT / BSP), grooved

Testing & documents

  1. Chemical and mechanical (tension, flattening, flare/bend) tests
  2. Hydrostatic test or non-destructive electric test (UT/ET) on each length
  3. Dimensional and visual inspection
  4. Intergranular corrosion (stainless), impact (low-temperature), hardness (sour service) when specified
  5. PMI and third-party inspection on request
  6. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 pipes →
Inconel 718 TubesAMS 5589 / 5590Specification & sizes
Inconel 718 tubes AMS 5589 / 5590

How it's madeSeamless tubes are hot-extruded or pierced and then cold-drawn or pilgered to size. Welded tubes are formed from strip, welded (TIG/laser/HF), bead-worked and drawn or sized. Heat-exchanger and boiler tubes are annealed after final forming, and U-tubes are bent and stress-relieved as required.

Specification
AMS 5589 / 5590
Size range
OD 3 mm to about 127 mm (¼" to 5") typical, wall 0.5 mm to 12 mm; BWG or mm; straight lengths up to about 30 m, U-bent to drawing
Finish
Annealed & pickled, bright annealed (BA), polished (sanitary), cold-drawn
Ends
Plain square-cut, deburred; U-bends with stress-relieved bends on request

Testing & documents

  1. Eddy-current and/or ultrasonic testing on each tube
  2. Hydrostatic or pneumatic test
  3. Flattening, flaring and flange tests
  4. Grain size (H grades), IGC and hardness when specified
  5. Surface roughness (Ra) for sanitary and instrumentation tube
  6. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 tubes →
Inconel 718 PlatesAMS 5596 / ASTM B670Specification & sizes
Inconel 718 plates AMS 5596 / ASTM B670

How it's madeSlabs are hot-rolled on a reversing plate mill (or a Steckel/hot-strip mill for thinner plate), then heat treated (annealed, normalised, or quenched and tempered, depending on material), descaled and pickled or shot-blasted. Plates are cut to size by plasma, oxy-fuel, waterjet or shearing.

Specification
AMS 5596 / ASTM B670
Size range
Thickness about 3 – 150 mm (and heavier on request), widths 1,000 – 3,000 mm, lengths 2,000 – 12,000 mm; cut-to-size and profile-cut parts
Finish
No.1 (hot-rolled, annealed and pickled) for stainless; shot-blasted, mill scale or primed for carbon steel
Ends
Mill edge, sheared, plasma or waterjet cut, profile cut to drawing

Testing & documents

  1. Chemical analysis and tensile tests (per plate or heat)
  2. Impact tests for low-temperature and pressure-vessel plates
  3. Ultrasonic testing (e.g. ASTM A435 / A578) when specified
  4. IGC, HIC and simulated PWHT tests as required
  5. Flatness and dimensional inspection
  6. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 plates →
Inconel 718 SheetsAMS 5596 / 5597Specification & sizes
Inconel 718 sheets AMS 5596 / 5597

How it's madeHot-rolled coil is cold-rolled to final thickness, then annealed and pickled (2B/2D) or bright annealed (BA), temper-passed, and polished or textured as needed. Coils are then levelled and cut into sheets.

Specification
AMS 5596 / 5597
Size range
Thickness about 0.3 – 6 mm, standard sizes 1,000 × 2,000, 1,219 × 2,438 (4 × 8 ft), 1,250 × 2,500 and 1,500 × 3,000 mm; custom cut lengths
Finish
2B, 2D, BA, No.4 (brushed), HL (hairline), No.8 (mirror), embossed, PVC or laser-film protected
Ends
Sheared or slit edges; laser-cut blanks on request

Testing & documents

  1. Chemical and mechanical tests
  2. Surface and finish inspection
  3. Thickness and flatness checks
  4. Hardness and bend tests as specified
  5. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 sheets →
Inconel 718 BarsASTM B637 / AMS 5662 / 5663 / API 6A718Specification & sizes
Inconel 718 bars ASTM B637 / AMS 5662 / 5663 / API 6A718

How it's madeBillets are hot-rolled or forged to size, then heat treated (annealed, solution treated, or quenched and tempered) and finished by descaling, peeling, turning, cold-drawing or centreless grinding for bright bar with tight tolerance.

Specification
ASTM B637 / AMS 5662 / 5663 / API 6A718
Size range
Round bars about 3 – 500 mm diameter; hex 6 – 100 mm A/F; square and flat sections to order; lengths 3 – 6 m random or cut to size
Finish
Black (hot-rolled), peeled, bright drawn, centreless ground and polished (h9 / h11 tolerance)
Ends
Saw-cut, chamfered on request

Testing & documents

  1. Chemical and mechanical tests
  2. Ultrasonic testing for internal soundness
  3. Hardness, IGC and impact tests as specified
  4. Straightness and tolerance checks
  5. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 bars →
Inconel 718 FlangesASTM B637 forgingsSpecification & sizes
Inconel 718 flanges ASTM B637 forgings

How it's madeFlanges are forged from billets (or cut from plate for some blind and plate flanges), heat treated to the material specification, and machined: bore, face, raised face or ring groove, bolt holes and hub bevel.

Specification
ASTM B637 forgings
Size range
NPS ½" – 24" (B16.5), 26" – 60" (B16.47 Series A/B); Class 150, 300, 600, 900, 1500, 2500; EN 1092-1 PN 6 – PN 100 on request
Finish
Raised face (RF), flat face (FF) or ring-type joint (RTJ); serrated spiral or concentric face finish (typically 3.2 – 6.3 µm Ra)
Ends
Weld-neck bevel matched to pipe schedule; socket bore; threaded

Testing & documents

  1. Chemical and mechanical tests of the forging
  2. Dimensional inspection to ASME B16.5 / B16.47
  3. Hardness, impact and IGC tests as specified
  4. Ultrasonic testing of forgings on request
  5. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 flanges →
Inconel 718 BoltsASTM B637 / AMS 5662Specification & sizes
ASTM A193 B7 stud bolt with two A194 2H heavy hex nuts Side elevation of a fully threaded stud bolt with chamfered ends and two heavy hex nuts, showing the stud length dimension and grade markings. 2H 2H Stud length L (end to end, per flange bolting tables) B7 mark on one end Heavy hex nut A194 2H Continuous thread

How it's madeCut from heat-treated bar (or forged and heat treated), then threaded by rolling or cutting, and coated if required.

Specification
ASTM B637 / AMS 5662
Size range
M6 – M100 and ¼" – 4" (larger on request); lengths to flange tables or drawing
Finish
Plain, black oxide, zinc, hot-dip galvanised, PTFE-based fluoropolymer, zinc-nickel
Ends
Chamfered points; full or partial thread

Testing & documents

  1. Chemical and mechanical tests of bar and finished bolts
  2. Hardness tests
  3. Proof-load and wedge tests where applicable
  4. Coating thickness and adhesion
  5. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 bolts →
Inconel 718 NutsASTM B637Specification & sizes
Inconel 718 nuts ASTM B637

How it's madeHot-forged or cold-formed from bar, heat treated (for hardenable grades), tapped and coated if required.

Specification
ASTM B637
Size range
M6 – M100 and ¼" – 4"; heavy hex to ASME B18.2.2; metric to ISO 4032 / 4033
Finish
Plain, zinc, galvanised (tapped oversize), fluoropolymer

Testing & documents

  1. Proof-load tests
  2. Hardness tests
  3. Chemical analysis
  4. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 nuts →
Inconel 718 WashersAMS 5596Specification & sizes
Inconel 718 washers AMS 5596

How it's madeStamped or machined from plate or strip and heat treated where required.

Specification
AMS 5596
Size range
M6 – M100 and ¼" – 4" bolt sizes
Finish
Plain, zinc, galvanised

Testing & documents

  1. Hardness tests
  2. Dimensional checks
  3. EN 10204 3.1 certificate; 3.2 with third-party inspection
Request a quote for inconel 718 washers →

Where is Inconel 718 used?

Typical applications

  • Aero-engine discs, shafts and casings
  • Oil and gas downhole tools and hangers
  • Wellhead and valve components (API 6A718)
  • High-strength fasteners and springs
  • Cryogenic tankage

Where do we supply Inconel 718?

Inconel 718 is regularly requested for projects in these markets:

What should you specify when buying Inconel 718?

  • Grade and specification, e.g. To order
  • Product form, size and tolerance
  • Heat treatment / condition and surface finish
  • Quantity, delivery location and required date
  • Tests: PMI, hydro/NDT, IGC, impact or hardness as required
  • Certificate type (EN 10204 3.1 / 3.2) and third-party inspection

See our RFQ checklist guide and what drives metal prices.

Explore more on Inconel 718

Frequently asked questions

Is Inconel 718 heat treatable?

Yes. It's solution treated and then aged (typically a two-step age) to develop its high strength.

Inconel 718 vs 625: which is stronger?

Aged 718 is much stronger, with yield above 1,000 MPa against about 400–500 MPa for 625. 625 has better corrosion resistance and weldability.

What is Inconel 718 used for?

Aero-engine discs, shafts and casings, Oil and gas downhole tools and hangers, Wellhead and valve components (API 6A718), High-strength fasteners and springs. It's used across Aerospace, Oil & Gas, Power Generation, Nuclear.

What is the UNS number of Inconel 718?

Inconel 718 is designated UNS N07718; the closest EN cross-reference is 2.4668.

Which product forms is Inconel 718 available in?

Pipes, Tubes, Plates, Sheets, Bars, Flanges, Bolts, Nuts, Washers, to To order, AMS 5589 / 5590, AMS 5596 / ASTM B670 and related specifications.

What is the density of Inconel 718?

About 8.19 g/cm³ (8190 kg/m³), used for weight calculations.

Is Inconel 718 magnetic?

Non-magnetic.

What temperature can Inconel 718 withstand?

High strength to about 650 °C; also excellent at cryogenic temperatures.

Need Inconel 718?

Share form, size, quantity and destination. We supply Inconel 718 from stock or mill-sourced, exporting to the GCC, Europe, USA, UK & Asia.

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