718/Inconel® Nickel Alloy Bar
Nickel Alloy 718, commonly known as UNS N07718, is a precipitation hardening nickel-chromium alloy containing significant amounts of iron, columbium, and molybdenum, along with lesser amounts of aluminum and titanium.
Nickel Alloy 718 maintains high strength and good ductility and oxidation resistance up to high temperatures; conversely it has outstanding cryogenic properties. An example of these combined characteristics used in one application can be seen in the aerospace industry. Nickel Alloy 718 provides vital strength aircrafts require, it can withstand both the intense heat of the afterburners and the freezing temperatures experienced at high altitude.
NSA offers many different conditions of Nickel Alloy 718: AMS 5662 solution treated, AMS 5663 solution treated and aged, AMS 5664 solution treated and aged, NACE MR-01-75, and many customer specific conditions.
AMS 5662 is the rawest state of 718, and the softest condition of the AMS group. It can be heat treated into AMS 5663; this heat treatment can be done in two ways to achieve specific outcomes such as optimum impact properties, or optimum tensile and creep-rupture properties. The hardness of AMS 5662 is about 20-25 HRC and can increase upon aging to about 36-44 HRC. Some prefer to machine their parts in AMS 5662 and later heat treat to their desired specification to the softness of the material, while others prefer the opposite machining their parts afterwards. Regardless, the same outcome of AMS 5663 is achieved.
AMS 5564 is different than the other AMS specifications; it has a more complicated forming process and is available through NSA upon mill run. The outcome is a higher tensile and yield strength, along with specific grain size restrictions. These restrictions enable AMS 5664 to have a higher strength which is desired for some aerospace applications.
NACE MR-01-75, produced in accordance with API (American Petroleum Institute), is in a separate category than the AMS conditions. NACE conditions of 718 have an adjusted chemistry which allows for the material to have a different range of characteristics. NACE conditions have a tighter element content range in addition to adjusted annealing and aging temperatures which produces a product with lower mechanicals, larger grain and increase toughness. NACE can be achieved through heat treating the AMS material but it is extremely complicated and not recommended. It is produced satisfactorily at the mill in a group of its own, as the chemical composition is slightly different than the AMS grades. Although this composition is special, the material is still recognized as UNS N07718. The tensile and yield are lower as well as the hardness which is about 40 HRC max which is lower than that of the AMS specifications depending on how much they were aged. These combined physicals make 718 NACE the preferred condition for many oil, offshore, and OEM applications.
Industries that use 718 include:
- Chemical processing
- Oil and Gas
Products partially or completely constructed of 718 include:
- Cryogenic storage tanks
- Downhole shafting
- Gas turbine components
- High strength bolting
- Jet engines
- Nuclear fuel element spacers
- Pump parts
- Pump shafts
- Rocket motors
- Thrust reversers
|AMS 5662||Stocking Diameters||1/2” to 8”|
|Material Lengths||Up to 20’|
|NACE/API||Stocking Diameters||1/2” to 8”|
|Material Lengths||Up to 20’|
|B-637||An age hardenable alloy with elevated strength up to 1300° F, withstands corrosion and has fantastic welding applications.|
|.08||.35||.015||.015||.35||17. – 21.||50. – .55||2.8 – 3.3||.3||Co 1.
Cb + Ta = 4.75 – 5.5
Ti .65 – 1.15
Al .2 – .8
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