Alloy 800 H/HT
Alloy 800 H/HT | UNS N08810 & N08811 | 1.4958 & 1.4959 are solid solution strengthened, iron-nickel-chromium alloys, typically offered as one, dual certified alloy meeting the elemental requirements of both alloys. The principle difference between alloy 800H and 800HT® material is the restricted aluminum and titanium content in 800HT®, which results in higher creep and stress rupture properties. Both Alloy 800H and 800HT® are superior to Alloy 800 (UNS N08800), having greater creep and stress rupture properties. The alloy is typically used for applications involving long-term exposure to high-temperatures where resistance is needed from oxidation, carburization and other types of high-temperature corrosion. Hydrocarbon processing, heat-treat furnaces and power generation are some of the most common applications where 800H & 800HT® is utilized. Pressure vessels and vessel components constructed from 800H and 800HT® are approved under the ASME, Boiler and Pressure Vessel Code, Section VIII, Division 1.
High nickel and chromium contents in both alloy 800H and 800HT® result in excellent resistance to oxidation, carburization and sulfidation. The high nickel content also increases the resistance to nitriding, although not as good as other alloys such as Alloy 600, which contains a higher percentage of nickel.
Typical industrial sectors:
• Steam / hydrocarbon reforming
• Ethylene pyrolsis tubing
• Ethylene dichloride cracking tubes
• Components, eg. Heat exchangers, piping systems, etc
• Steam generators tubing in helium coolant, high temperature reactor systems