718

718

Inconel 718 is a high strength nickel base superalloy used for cryogenic temperatures up to long term service at 1200°F. The alloy is readily fabricated and may be welded in either the annealed or precipitation (age) hardened condition. Anneal 1700 -1850°F, air cool or faster. Age 1325°F 8 hours, furnace cool to hold at 1150°F, for a total aging time of 18 hours, air cool. Alloy 718 will show a contraction of 0.0008 inch/inch after precipitation hardening. 

Chemistry

 Ni+CoCrCb+TaMoTiAlCoCMnSiPSBCuFe
MIN 50.00 17.00 4.75 2.80 0.65 0.20 -- -- -- -- -- -- -- -- --
MAX 55.00 21.00 5.50 3.30 1.15 0.80 1.00 0.08 0.35 0.35 0.015 0.015 0.006 0.30 Balance

Specifications

AMS 5596, AMS 5662, AMS 5663, AMS 5832
ASME Case 2222-1, ASME SFA 5.14
ASTM B 637, ASTM B 670
EN 2.4668
GE B50TF14, GE B50TF15
UNS N07718
Werkstoff 2.4668

Inventory

718 Plate, 718 Round Bar, 718 Sheet, 718 Welding Products

Common Trade Names

Alloy 718, Inconel® 718, Nickel 718

Features

  • Good mechanical properties: tensile, fatigue and creep-rupture
  • Excellent welding characteristics, resistant to postweld age cracking
  • Oxidation resistant throughout its useful temperature range

Applications

  • Gas turbine engine parts
  • Liquid fuel rocket motor components
  • Springs, fasteners
  • Cryogenic tanks

Physical Properties

Density: 0.296 lb/in3 annealed, 0.274 lb/in3 aged
Melting Point: 2410 - 2540°F

Temperature, °F -320 70 200 400 600 1000 1200 1400
Coefficient* of Thermal Expansion, in/in°F x 10-6 5.9 - 7.3 7.5 7.7 8.1 8.4 8.9
Thermal Conductivity
Btu • ft/ft2 • hr • °F
- 6.4 7.2 8.2 9.3 11.3 12.3 13.3
Modulus of Elasticity, Dynamic psi x 106 - 29 28 27 26 25 24 22

* 70°F to indicated temperature.

Mechanical Properties

Typical Room Temperature Properties, 1800°F Annealed Condition

Ultimate tensile strength, ksi 135
0.2% yield strength, ksi 70
Elongation, % 45
Hardness, Rockwell B 100

Average Tensile Properties, ½" Bar Annealed 1800°F, Aged 1325/1150°F

Temperature, °F 70 400 800 1000 1200 1400
Ultimate Tensile Strength, ksi 210 198 191 185 168 111
0.2% Yield Strength, ksi 175 163 156 155 149 110
Elongation, % 22 20 19 18 19 27
Hardness, Rockwell C 42 - 44 - - 40 - 41 40 - 41 33 - 34

Typical Stress Rupture, Bar, Annealed 1800°F, Aged 1325/1150°F

Temperature, °F 1100 1200 1300 1400
100 Hours, ksi 170 110 75 44
1,000 Hours, ksi 130 85 55 25

INCONEL® and INCOLOY® are registered trademarks of Special Metals (PCC)