Special Metals INCONEL Alloy 718

Subcategory: Metal; Nickel Base; Superalloy

Key Words: IN718, INCONEL 718, AFNOR NC 19 Fe Nb, UNS N07718; ASTM B637, B670; ASME Boiler Code Sections I, III; AMS 5589, AMS 5590, AMS 5596, AMS 5597, AMS 5662, AMS 5663, AMS 5664, AMS 5832, Werkstoff Nr. 2.4668; WL Nr. 2.4668; MIL-N-24469; NACE MR-01-75; AECMA Pr EN 2404, 2405, 2407, 2408, 2952, 2961, 3219

Component   Wt. %
Al0.2 - 0.8 
BMax 0.006 
CMax 0.08 
CoMax 1 
Cr17 - 21 
Component   Wt. %
CuMax 0.3 
MnMax 0.35 
Mo2.8 - 3.3 
Nb4.75 - 5.5 
Component   Wt. %
Ni50 - 55 
PMax 0.015 
SMax 0.015 
SiMax 0.35 
Ti0.65 - 1.15 

Material Notes:
Nickel content above includes cobalt. Iron content as remainder. Developed in the early 1960's, IN718 is still considered the material of choice for the majority of aircraft engine components with service temperatures below 1200F (650C). Inconel 718 is a precipitation-hardenable nickel-chromium alloy containing also significant amounts of iron, niobium, and molybdenum along with lesser amounts of aluminum and titanium. It combines corrosion resistance and high strength with outstanding weldability including resistance to postweld cracking. The alloy has excellent creep-rupture strength at temperatures to 1300F (700C).

Applications: Aerospace, gas turbines, rocket motors, spacecraft, space shuttles, nuclear reactors, pumps, turbo pump seals, and tooling.

Forms: round, flat, extruded section, pipe, tube, forging stock, plate, sheet, strip and wire.

Data provided by the manufacturer, Special Metals.

Physical PropertiesMetricEnglishComments
Density8.19 g/cc0.296 lb/in 

Mechanical Properties
Tensile Strength, Ultimate1375 MPa199000 psi Precipitation Hardened. Value at room temperature.
Tensile Strength, Ultimate at Elevated Temperature1100 MPa160000 psi Precipitation Hardened prior to test; 650C
Tensile Strength, Yield1100 MPa160000 psi Precipitation Hardened. Value at room temperature; 0.2% offset.
Tensile Strength, Yield at Elevated Temperature980 MPa142000 psi Precipitation Hardened prior to test; 0.2% offset; 650C
Elongation at Break25 %25 % Precipitation Hardened
Elongation at Break at Elevated Temperature18 %18 % Precipitation Hardened prior to test.; 650C

Electrical Properties
Electrical Resistivity0.000125 ohm-cm0.000125 ohm-cm 
Magnetic Permeability1.00111.0011 at 200 oersted (15.9 kA/m)
Curie Temperature-112 C-170 F 

Thermal Properties
CTE, linear 20C13 m/m-C7.22 in/in-F 20-100C
Specific Heat Capacity0.435 J/g-C0.104 BTU/lb-F 
Thermal Conductivity11.4 W/m-K79.1 BTU-in/hr-ft-F 
Melting Point1260 - 1336 C2300 - 2440 F 
Solidus1260 C2300 F 
Liquidus1336 C2440 F 

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