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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+Co | Cr | Cb+Ta | Mo | Ti | Al | Co | C | Mn | Si | P | S | B | Cu | Fe | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 SB 637, ASME SFA 5.14, ASME SFA 5.14 (ERNiCrMo-11)
ASTM B 637, ASTM B 670
EN 2.4668
GE B50TF14, GE B50TF15
MSRR 7115, MSRR 7116
UNS N07718
Werkstoff 2.4668
Inventory
718 Plate, 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)