Inconel® alloy 718

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Applications

Alloy 718 combines properties which make it suitable for a variety of fabricated component applications in both aircraft turbine engines and land-based turbines. These include seals, bellows, and many types of stamped metal components. The alloy is used in downhole and well head components for oil and gas wells.

Description

Inconel^® 718 is an age-hardenable Nickel-Chromium-Columbium (Niobium)-Molybdenum alloy with high strength, corrosion-resistance, and good fabrication characteristics. Inconel^® 718 has high tensile, yield, and creep-rupture properties at high temperatures up to 1200°F (650°C). 

Industries Supplied

Oil & Gas Extraction, Nuclear, Aerospace, Defense and Automotive.

Nominal Composition

C: 0.08 max
Mn: 0.35 max
Si: 0.35 max
P: 0.015 max
S: 0.015 max
Cr: 17.0 – 21.0 
Ni: 50.0 – 55.0 
Mo: 2.80 – 3.30 
Nb: 4.75 – 5.50
Ti: 0.65 – 1.15
Al: 0.20 – 0.80
Co: 1.0 max 
Fe: Balance

Physical Properties

Density: 0.296 lb/in³, (8.19 g/cm³)

Modulus of Elasticity (E): 
At 70°F (20°C): 29 x 10³ ksi (200 GPa)

Modulus of Rigidity (G)
At 70°F (20°C):  11.6 x 10³ ksi (80 GPa)

Coefficient of Expansion:
7.7 µin/in.-°F (70°F to 600°F)
13.9 µm/m-°C (20°C to 538°C)

Electrical Resistivity: 47.5 µΩ.in, (121 µΩ.cm)

Thermal Conductivity: 79 Btu-in/ft²hr-°F, (11.4 W/m-K)

Applicable Specifications

Strip and Foil: AMS 5596, AMS 5597, ASTM B670

Typical Mechanical Properties

• Annealed
  • Heat Treatment: 1800°F (980°C)
  • Tensile Strength: 120 – 140 ksi (830 – 965 MPa)
  • Suggested Operating Conditions: -330°F to 1200°F (-200°C to 650°C)
• Spring Temper
  • Tensile Strength: 180 – 230 ksi (1240 – 1585 MPa)
  • Suggested Operating Conditions: -330°F to 1200°F (-200°C to 650°C)
• After Precipitation Heat Treat
  • Heat Treatment: Per AMS 5596
  • Tensile Strength: 190 – 240 ksi (1310 – 1655 MPa)
  • Suggested Operating Conditions: -330°F to 1200°F (-200°C to 650°C)

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INCONEL^® is a registered trademark of the Special Metals Corporation group of companies.

For further information Contact:

Email: stripinfo@elgiloy.com
Phone: 1 888 843 2350 
Elgiloy Specialty Metals – Strip Products
1565 Fleetwood Dr.
Elgin, IL 60123 USA 

Additional Information on Inconel® 718

No matter if you are producing springs, valves, or other components for a machine that will experience extremely high temperatures, Inconel® 718 strip is one of the most highly sought-after alloys by professionals in the industry. Turbine engines and aircraft are the most common places where this alloy can be found, but it is very useful for many different types of machinery. At Elgiloy, we provide 718 for our customers who are looking for peak performance in extreme conditions.

Inconel® 718 strip is a precipitation hardened, Nickel-based, super alloy that can withstand extreme temperatures both in the hot and cold end of the spectrum. It is made up of mainly Nickel, Chromium, and Columbium, with trace amounts of other elements. It is very strong, corrosion resistant, and maintains great fabrication characteristics.  Perhaps the most useful characteristic of 718 Inconel® is its performance at very high temperatures. It is resistant to creeping and has a high rupture strength threshold. While it may seem that it would be difficult to weld due to its durability in hot temperatures, the poor age hardening response of the alloy allows for relatively easy weldability especially using a gas tungsten arc welder.

As stated before, 718 strip from Inconel® can be easily welded and will not toughen or crack during the process. This is also true during extremely frigid temperatures, down to even -400 degrees, where this alloy maintains its strength and performance. Once heat processing begins, Inconel® 718 will age harden. This shows the extreme versatility of this alloy as a whole. No matter if you are using it or processing it in very hot or very cold temperatures, it will still operate at peak performance. 718 strip can also be roll threaded only after full aging using induction heat and without increasing the size of the grain.

When you are shaping or machining Inconel® 718 strip alloy, be aware that the quick work hardening of the alloy makes using conventional methods much more complicated. After the initial machining pass, deformation can occur in either the alloy or your tool because of work hardening for the next subsequent passes. This is why most use a hostile and mild cut hard tool when it is machined, mainly because it limits the amount of passes necessary to complete the process. Ultimately, it is best to machine the alloy in a solution form. This way only the final steps are necessary followed by age hardening. If you are cutting a plate of 718 Inconel®, consider using a waterjet cutter, or selective laser melting, even just for the 718 components.

At Elgiloy, we offer our customers Inconel® products because of their outstanding track record among professionals in many different industries. The 718 strip is no exception. At extremely competitive prices, it is absolutely worth making sure that you can trust the materials you are working with to ensure that you will spend less time maintaining your equipment, and more time doing your job efficiently. Whether you are working on a jet engine, or any other piece of equipment that will experience extremely high temperatures, Inconel® 718 is the alloy for you.