Incoloy 800
Incoloy 800 (UNS N08800) is an iron-nickel-chromium alloy (nominal 32% Ni, 21% Cr, balance Fe) combining high-temperature strength with outstanding resistance to oxidation, carburization, and sulfidation. Developed by Special Metals Corporation, the 800-family alloys were specifically engineered for service in high-temperature process environments where plain stainless steels would rapidly oxidize, carburize, or corrode in aggressive gas-phase media. Continuous service to 1500°F (816°C) in oxidizing and mildly reducing atmospheres is the design envelope for standard Incoloy 800.
The family also includes Incoloy 800H (higher carbon for improved creep resistance) and 800HT (Ti and Al additions for improved high-temperature properties), governed by ASTM B407/B408 for pipe/bar and AMS 5766 for the premium aerospace bar and forging form. All three variants share the same basic Ni-Cr-Fe composition and are available in the complete range of wrought product forms.
Product Forms & Size Range of Incoloy 800
Incoloy 800 bar and rod per ASTM B408 is available in diameters from 0.188 inch to 8.000 inches in the annealed condition. Bar is used for precision machined components including valve bodies, fastener shanks, and structural fittings for high-temperature chemical process and power generation systems. Wire and rod for fastener and spring production are available in smaller diameters.
HEAT TREATMENT OF INCOLOY 800
Incoloy 800 is solution annealed at 1800–1900°F (982–1038°C) and rapid-quenched to produce a fully austenitic structure. It is not hardenable by precipitation. Incoloy 800H and 800HT require higher annealing temperatures (2100°F / 1149°C minimum) to achieve the specified grain growth that improves creep resistance for elevated-temperature pressure vessel service. Stress relief at 1650°F (899°C) followed by controlled cooling is used for weldments in high-temperature service to minimize residual welding stresses.
Incoloy 825
Ni-Fe-Cr alloy with Mo and Cu — exceptional resistance to both oxidizing and reducing acids including sulfuric and phosphoric acid environments.
Haynes Alloy 230
Ni-Cr-W-Mo alloy with outstanding high-temperature strength and oxidation resistance to 2100°F for gas turbine combustion applications.
Certified Material for Critical Service
Incoloy 800 is supplied to ASTM B408 (bar and rod, UNS N08800/N08810) and ASTM B409 (plate, sheet, strip). AMS 5766 covers the premium aerospace-grade bar and forging form of Incoloy 800H/800HT. All forms are supplied solution annealed with certified mill test reports per the applicable specification.