Alloy 800 is an iron-nickel-chromium alloy with moderate strength and good resistance to oxidation and carburization at elevated temperatures. It is particularly useful for high-temperature equipment in the petrochemical industry because the alloy doesn’t form the embrittling sigma phase after long time exposure at 1200°F (649°C). Excellent resistance to chloride stress-corrosion cracking is another important feature of alloy 800.
Alloy 800H is a solution heat treated (2100°F/1150°C), controlled-carbon version of alloy 800 with improved elevated temperature properties. It has improved creep and stress-rupture characteristics in the 1100°F (593°C) to 1800°F (982°C) temperature range.
Typical applications for alloy 800 and 800H are – Heat exchangers and process piping; carburizing fixtures and retorts; furnace components; electric range heating-element sheathing; extruded tubing for ethylene and steam methane reforming furnaces; ammonia effluent coolers.