AMS 5590 is a designation of Nickel Inconel 718, itself a nickel-chromium alloy with high strength, corrosion and oxidation resistance, and excellent tensile and impact strength at cryogenic temperatures.
Full chemical composition is 52.5Ni – 19Cr – 3.0Mo – 5.1Cb – 0.90Ti – 0.50Al – 18Fe.
This designation is made by solution annealing at 1950°F (1065°C) followed by rapid cooling, usually in water, and precipitation hardening is done at 1400°F (760°C) for 10 hours and furnace cool to 1200°F (650°C), then aging at the same temperature for 20 hours.
It is available as tubing and thus it is best suited for fluid lines and components that require resistance and stress-rupture of up to 1300°F (705°C), and oxidation resistance of up to 1800°F (982°C).
AMS 5590 is an excellent choice for tensile-limited applications. It has the best transverse ductility in heavy sections, better impact strength, and low-temperature notch strength.
Efficiency when welding is about 100% with the gas tungsten-arc process and using the proprietary Nickel Filler Metal 718. Nickel Inconel 718 AMS 5590 can be age-hardened directly, without stress relief.