Nominal Composition
Nickel 52%, Chromium 19%, Iron 18%,
Columbium 5%, Molybdenum 3%, Titanium 1%

Description
Alloy 718 is a precipitation-hardening nickel-chromium alloy containing significant amounts of iron, columbium, and molybdenum, along with lesser amounts of aluminum and titanium. Alloy 718 maintains high strength and good ductility up to 1300°F (704°C). This alloy has relatively good weldability, formability, and excellent cryogenic properties compared to other precipitation hardening nickel alloys. The sluggish precipitation hardening response of this alloy allows it to be readily welded without hardening or cracking.

Properties
Non-magnetic. Good corrosion resistance and oxidation resistance in jet engine and gas turbine applications. This alloy is used for parts requiring high resistance to creep and stress rupture up to 1300°F (704°C) and oxidation resistance up to 1800°F (982°C). Alloy 718 exhibits excellent tensile and impact properties even at cryogenic temperatures. AMS 5662 requires minimum yield strength of 150,000 psi at room temperature.

Hardness
Hardness of Aerodyne stock is typically 225 BHN and a maximum of 277 BHN by specification. Classified as a precipitation-hardening alloy that can be age hardened by heat treatment. Grain structure remains austenitic at all temperatures. Various solution and aging treatments are used during heat treatment of this grade to optimize either short or long time elevated temperature mechanical properties.

Machinability
RATING: 12% of B-1112

TYPICAL STOCK REMOVAL RATE:
20 surface feet/minute with high-speed tools.
80 surface feet/minute with carbide.

COMMENTS:
Carbide tooling preferred for turning operations, but high speed steel preferred for milling (to avoid tooth chipping). Use relatively heavy cuts and low speeds to minimize surface work hardening. Roughing cuts are usually made before hardening, finishing cuts after hardening. Allow a contraction due to hardening of about 0.001 inch per inch of the workpiece dimensions.

Density: 0.297 lbs/in3, 8.22 g/cm3

Standard Inventory Specifications
· AMS 5662
· GE B50TF15 Class D
· PWS S-5662
· ASME-SB 637
· Capable of AMS 5663
· Line marked over 0.5 inches in diameter
· Predominately produced by VIM-VAR melt method. Hot worked, solution treated (annealed), then centerless ground or rough turned.
· Lengths: 10-12 feet

The Nickel 718 alloy steel product specification will be available soon and will include details about nominal composition, 718 product description, 718 alloy steel properties, hardness, machinability, and density.


Standard Inventory Specifications
GE B50A809C