The Home of HASTELLOY® and HAYNES® alloys

Principal Features

Excellent High-Temperature Strength Up to 1200°F (650°C), Good Ductility, Formability, and Weldability
HAYNES® 718 alloy (UNS # N07718) is an age-hardenable nickel-iron-chromium-columbium-molybdenum-titanium-aluminum alloy designed to combine excellent strength with good fabrication characteristics in the annealed condition. While limited to applications below 1200°F (650°C), it is significantly stronger at these lower temperatures than materials such as Waspaloy alloy, R-41 alloy, or X-750 alloy. It is also much easier to weld than these alloys, and is less susceptible to the strain age cracking problems common for gamma prime strengthened materials.

HAYNES 718 alloy is normally only used for component applications up to 1200°F (650°C); however, its oxidation resistance is comparable to that for other gamma-prime-strengthened superalloys.

Fabrication
HAYNES 718 alloy has very good forming and welding characteristics. The hot working temperature range for the alloy is approximately 1700 to 2100°F (985-1150°C). The alloy has very good ductility in the annealed condition and thus, may also be formed by cold working. Intermediate annealing in the temperature range from 1700 to 1850°F (925 to 1010°C) may be needed for complex component forming operations. All hot- or cold-worked parts should be annealed and rapidly cooled in order to restore the best balance of properties.

HAYNES 718 alloy can be welded by both manual and automatic welding methods, including gas tungsten arc (TIG), gas metal arc (MIG), electron beam, and resistance welding. Matching composition filler wire is available and is generally used for welding 718 alloy.

Heat Treatment
Wrought HAYNES 718 alloy is furnished in the solution heat-treated condition unless otherwise specified. The alloy is normally solution heat-treated at 1700 to 1850°F (925 to 1010°C) and rapidly cooled or water quenched for optimal properties. Following solution heat treatment, the alloy is normally age-hardened by a two step treatment consisting of 1325°F (720°C) for 8 hours, furnace cooling to 1150°F (620°C), holding for an additional 8 hours, and then air cooling.

Available in Convenient Forms
HAYNES 718 alloy is produced in the form of sheet, strip, plate, bar, billet, wire, and tubular products.

Applications
HAYNES 718 alloy combines properties which make it suitable for a variety of fabricated component applications in both aircraft turbine engines and land-based turbines. These include rings, casings, and many types of formed sheet metal components. It is also used for fasteners and instrumentation parts. The alloy is used in down hole and well head components for oil and gas wells.

Applicable Specifications
HAYNES 718 alloy is covered by the following specifications: AMS 5596/5597 (sheet, strip, and plate), AMS 5662/5664 (bar and billet), AMS 5832 (wire), AMS 5589/5590 (seamless tubulars); NACE MR-01-75 (oil field equipment); and ASTM B-626 (welded tubing). The UNS number for this material is N07718.


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