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. % Al 0.2 - 0.8   B Max 0.006   C Max 0.08   Co Max 1   Cr 17 - 21

Component    Wt. % Cu Max 0.3   Fe 17   Mn Max 0.35   Mo 2.8 - 3.3   Nb 4.75 - 5.5

Component    Wt. % Ni 50 - 55   P Max 0.015   S Max 0.015   Si Max 0.35   Ti 0.65 - 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 1200°F (650°C). 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 1300°F (700°C).

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 Properties	Metric	English	Comments
Density	8.19 g/cc	0.296 lb/in³
Mechanical Properties
Tensile Strength, Ultimate	1375 MPa	199000 psi	Precipitation Hardened. Value at room temperature.
Tensile Strength, Ultimate at Elevated Temperature	1100 MPa	160000 psi	Precipitation Hardened prior to test; 650°C
Tensile Strength, Yield	1100 MPa	160000 psi	Precipitation Hardened. Value at room temperature; 0.2% offset.
Tensile Strength, Yield at Elevated Temperature	980 MPa	142000 psi	Precipitation Hardened prior to test; 0.2% offset; 650°C
Elongation at Break	25 %	25 %	Precipitation Hardened
Elongation at Break at Elevated Temperature	18 %	18 %	Precipitation Hardened prior to test.; 650°C
Electrical Properties
Electrical Resistivity	0.000125 ohm-cm	0.000125 ohm-cm
Magnetic Permeability	1.0011	1.0011	at 200 oersted (15.9 kA/m)
Curie Temperature	-112 °C	-170 °F
Thermal Properties
CTE, linear 20°C	13 µm/m-°C	7.22 µin/in-°F	20-100°C
Specific Heat Capacity	0.435 J/g-°C	0.104 BTU/lb-°F
Thermal Conductivity	11.4 W/m-K	79.1 BTU-in/hr-ft²-°F
Melting Point	1260 - 1336 °C	2300 - 2440 °F
Solidus	1260 °C	2300 °F
Liquidus	1336 °C	2440 °F