Incoloy 800 (UNS N08800)

Incoloy 800 (also specified as UNS N08800) is a nickel-iron-chromium alloy with a fully austenitic single-phase structure after rapid cooling from elevated temperature. It combines good high-temperature stability and strength with excellent resistance to a wide range of corrosive media, and is a widely specified material for heat-transfer, furnace and nuclear-service components.

Overview

• Category: Austenitic Ni-Fe-Cr heat-resistant / corrosion-resistant alloy
• Key feature: Excellent resistance to chloride stress-corrosion cracking, with good high-temperature oxidation, carburisation and sulfidation resistance below about 816 °C (1500 °F)
• Available forms: Round bar / rod, plate, sheet, pipe & tube, forgings, and custom profiles to order

Chemical Composition (wt%)

Physical Properties

Mechanical Properties (typical, annealed)

Key Features

• Corrosion resistance: excellent resistance to stress-corrosion cracking in chloride solutions, low-concentration NaOH aqueous solutions and high-temperature, high-pressure water. General corrosion resistance is superior to ordinary austenitic stainless steels and better than Inconel 600 in many media;
• High-temperature performance: good oxidation, carburisation and sulfidation resistance; retains strength and stability below 816 °C (1500 °F).

Fabrication & Welding

• Hot working: 1200–950 °C, followed by water quenching or fast air cooling. Solution treatment after hot working is required to restore optimum properties and creep resistance.
• Cold working: The work-hardening rate is higher than that of austenitic stainless steels, so suitable equipment must be selected. Cold-work material should be in the solution-treated condition; intermediate annealing is required for large cold reductions, and a second solution treatment is recommended when cold reduction exceeds about 10 %.
• Welding: Weldable to itself or to other metals by any conventional process, such as GTAW (TIG) and plasma arc welding. Pulsed arc welding is the preferred process; for SMAW (MMA), a shielding gas of Ar + He + H&sub2; + CO&sub2; is recommended.

Typical Applications

• Chemical industry: nitric-acid coolers, acetic-anhydride cracking tubes, heat-exchange equipment and piping systems;
• Nuclear industry: nuclear steam generators and steam-generator tubing;
• Heat-treatment industry: baskets, trays and fixtures for furnace equipment;
• Appliances: sheathing for electric heating elements;
• Petroleum processing: air-cooled heat exchangers for process streams.

For detailed datasheets, mill certificates (EN 10204 3.1) or inquiries on specific sizes and tolerances, please contact our sales & engineering team.