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“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

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

(1700°F-1850°F Solution Anneal)

Characteristics:


    • 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.

    • 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.


    • 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.