Incoloy 800H (UNS N08810)

Incoloy 800H (also specified as UNS N08810) is a nickel-iron-chromium alloy of the Incoloy 800 series. With controlled carbon content (0.05–0.10 %) and an appropriate annealed microstructure, it develops significantly higher creep and rupture strength above about 600 °C (1100 °F), while retaining good oxidation, sulfidation and carburisation resistance for long-term high-temperature service.

Overview

• Category: Austenitic Ni-Fe-Cr heat-resistant alloy (800 series)
• Key feature: Higher creep and rupture strength above 600 °C than Incoloy 800, with excellent oxidation resistance
• Available forms: Round bar / rod, plate, sheet, pipe & tube, forgings, and custom profiles to order

Chemical Composition (wt%)

Physical Properties

Mechanical Properties

Maintains high tensile strength even at 1090 °C (2000 °F).

Key Features

• High-temperature performance: excellent creep resistance above 600 °C, retaining good tensile strength up to about 1090 °C (2000 °F);
• Corrosion resistance: excellent in a wide range of corrosive environments, especially acidic media; the chromium- and aluminium-rich oxide film protects the alloy;
• Oxidation resistance: high chromium content forms a dense, stable chromium-oxide scale at temperature, preventing oxidant attack on the base metal;
• Thermal conductivity: good thermal conductivity due to high nickel content;
• Weldability: good weldability with almost no tendency to stress-corrosion cracking during welding.

Machining & Welding

• Machining: standard methods can be used; control cutting parameters to avoid work hardening.
• Welding: a range of processes can be used. ERNiCr-3 filler wire is recommended; for maximum mechanical strength, ERNiCrCoMo-1 wire or ENiCrCoMo-1 covered electrode may be selected.

Heat Treatment

• To avoid grain-boundary cracking caused by stress relaxation above 538 °C, post-weld heat treatment at 899 °C is required, holding for 1 hour per 25 mm of thickness (minimum 0.5 hour per 25 mm), then air cool.

Typical Applications

• Petrochemical: high-temperature, high-pressure processes such as hydrogen production, aromatics reforming and catalytic cracking — reactors, heat exchangers and piping;
• Nuclear: reactor steam generators, pressure vessels and high-temperature piping;
• Aerospace: aero-engine and combustor high-temperature components;
• Power generation: high-temperature heaters, crude-oil heaters and steam generators;
• Food processing: selected high-temperature food-processing applications.

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