AMS 5597 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 plate, sheet, and strip and is best suited for components that require high strength at cryogenic temperatures, such as cases and ducts.
AMS 5597 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 5597 can be age-hardened directly, without stress relief.