“Inconel 718: High-Strength, Corrosion-Resistant Nickel Alloy for Extreme Environments”
Introduction: Inconel 718 (UNS N07718/W.Nr. 2.4668) is a remarkable nickel-based superalloy known for its exceptional properties. Let’s delve into its characteristics, fabrication techniques, and diverse applications:
Chemical Composition | ||||||||||||||||
Weight % |
C |
Mn |
P |
S |
Si |
Cr |
Ni |
Mo |
Cb |
Ta |
Ti |
Al |
Co |
B |
Cu |
Fe |
Alloy 718 |
0.08 |
0.35 |
0.015 |
0.015 |
0.35 |
17-21 |
50-55 |
2.8-3.30 |
4.75-5.50 |
0.05 |
0.65-1.15 |
0.20-0.80 |
1 |
0.006 |
0.3 |
Rem |
AMS 5662 |
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Material |
Condition |
Tensile Strength Ksi |
Yield Strength Ksi |
Elongation (%) |
Hardness |
|||||||||||
AMS 5589 Tube |
Solution Annealed |
155 |
95 |
30 |
|
|||||||||||
AMS 5589 Tube |
Solution Annealed and Aging |
185 |
150 |
12 |
≥36 HRC |
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(1700°F-1850°F Solution Anneal) |
- High-Strength Alloy: Inconel 718 exhibits impressive tensile, fatigue, creep, and rupture strength, making it suitable for demanding environments.
- Corrosion Resistance: The alloy’s chromium content (17.00-21.00%) ensures excellent resistance to corrosion, even at elevated temperatures.
- Age-Hardenable: Inconel 718 can be strengthened through precipitation hardening, allowing for tailored mechanical properties.
- Weldability: Its welding characteristics, including resistance to postweld cracking, are outstanding.
- Fabrication Ease: The alloy can be readily fabricated into complex parts, making it versatile for various applications.
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- Techniques:
- Solution Annealing: Inconel 718 can be supplied in the “solution annealed” condition, where it is heat-treated to achieve optimal properties.
- Age Hardening: For even higher strength, the alloy can undergo “solution annealing and age hardening.”
- Fabrication: Inconel 718 is easily machined, formed, and welded, allowing for intricate designs and components.
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- Industries and Applications:
- Aerospace: Components for liquid-fueled rockets, rings, casings, and sheet metal parts in aircraft and gas turbine engines.
- Cryogenic Tankage: Inconel 718’s cryogenic properties make it suitable for storage tanks.
- Fasteners and Instrumentation: It is used in fasteners and precision instrumentation parts.
- Power Generation: Gas turbine components and heat exchangers.
- Chemical Processing: Reactor vessels, heat exchangers, and other corrosive environments.
Remember, Inconel 718’s versatility and robustness have made it a go-to material in critical applications across various industries.