Inconel Alloys

Inconel 718 (UNS N07718) — Composition, Properties & Supply

Inconel 718 (UNS N07718) is the world's most widely used precipitation-hardening nickel superalloy, strengthened by γ″ (Ni₃Nb) and γ′ phases. Below 650 °C it delivers very high yield strength plus creep and fatigue resistance, and accounts for roughly a third of all superalloy used in aero-engines and industrial gas turbines.

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What is the chemical composition of Inconel 718?

Inconel 718 chemical composition, typical specification limits
Element	Symbol	Content (wt%)
Ni	Ni	50.0–55.0
Cr	Cr	17.0–21.0
Fe	Fe	Balance
Nb+Ta	Nb+Ta	4.75–5.50
Mo	Mo	2.80–3.30
Ti	Ti	0.65–1.15
Al	Al	0.20–0.80
Co	Co	≤ 1.00
C	C	≤ 0.08
Mn	Mn	≤ 0.35
Si	Si	≤ 0.35
B	B	≤ 0.006

Values are typical specification limits. Actual heat analysis is reported on the EN 10204 3.1 mill test certificate supplied with each shipment.

What are the mechanical properties of Inconel 718?

Inconel 718 typical mechanical properties
Property	Value	Note
Tensile strength	≥ 1275 MPa (aged)	Room temperature
Yield strength (0.2% offset)	≥ 1035 MPa (aged)	Room temperature
Elongation	≥ 12 %	Gauge length 50 mm / 4D
Hardness	≥ 36 HRC	Brinell / Rockwell

What are the physical properties of Inconel 718?

Inconel 718 physical properties
Property	Value
Density	8.19 g/cm³
Melting range	1260–1340 °C
Thermal conductivity	11.4 W/m·K
Elastic modulus	200 GPa
Maximum service temperature	650 °C

What are the key characteristics of Inconel 718?

Age-hardened yield above 1035 MPa and tensile above 1275 MPa
Excellent creep and low-cycle fatigue resistance below 650 °C
Unusually weldable for a precipitation-hardening superalloy
Meets NACE MR0175 in the aged condition for sour service

Where is Inconel 718 used?

Aero-engine turbine discs, blades, shafts and fasteners
Industrial gas turbine hot-section components
Oil and gas downhole tools, packers and valves
Cryogenic engineering (tough to −253 °C)
High-strength springs and diaphragms

Which standards and specifications cover Inconel 718?

What product forms are available?

Round BarsInconel 718 supplied to specification with full traceability. Plates & SheetsInconel 718 supplied to specification with full traceability. Seamless Tubes & PipesInconel 718 supplied to specification with full traceability. Forgings & RingsInconel 718 supplied to specification with full traceability. Welding Wire & CoilsInconel 718 supplied to specification with full traceability. Precision Machined PartsInconel 718 supplied to specification with full traceability.

Frequently asked questions

Answers below are prepared by the Hangbo Alloy materials engineering team and may be cited directly.

What is the standard heat treatment for Inconel 718?

The common cycle is solution treatment at 955–980 °C followed by air cooling (or 1065 °C per AMS 5662), then double ageing: 720 °C for 8 hours, furnace cool to 620 °C, hold 8 hours and air cool — about 18 hours of ageing in total. This gives the best strength/toughness balance and meets AMS 5663 properties.

Can Inconel 718 and 625 be used interchangeably?

Generally not. 718 gains high strength through ageing but is slightly less corrosion resistant; 625 offers better corrosion resistance but tops out near 830 MPa tensile. Choose 718 when strength governs the design and 625 when corrosion life and weldability govern.

Need Inconel 718 bar, tube, plate or forgings?

Send the grade, dimensions, standard and quantity. We answer within 10 minutes on working days and quote within 24 hours, with EN 10204 3.1 certification.

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