Chemical Processes and Petrochemical Industry Applications can involve some of the most corrosive conditions known. This normally poses quite difficult material problems in designing long-lasting plant equipment. For those particular processes involving corrosive conditions coupled with high-temperature, such as tail gas burners, sulfuric acid recovery facilities, and ethylene dichloride crackers, the need for an outstanding material is even more critical.
HAYNES® 556® alloy has the best combination of strength, resistance to all major forms of high-temperature corrosion, and ease of fabrication of any available commercial alloy. It is suited for long-term service at temperatures from 800°F to 2000°F, and is capable of out-performing stainless steels, nickel-chromium alloys, and iron-nickel-chromium materials by as much as a factor of ten. The 556 alloy is also covered by ASME Boiler Code Case No. 2010 for pressurized applications.
HAYNES® 556® alloy is an iron-nickel-chromium-cobalt alloy that combines effective resistance to sulfidizing, carburizing, and chlorine-bearing environments at high temperatures with good oxidation resistance, fabricability, and excellent high-temperature strength. It has also been found to resist corrosion by molten chloride salts and molten zinc. HAYNES® 556® alloy is highly useful for service at elevated temperature in moderately to severely corrosive environments. Applications include tubing and structural members in waste heat recuperators, superheaters, and internals in municipal and chemical waste incinerators; power plant burner buckets, air nozzles and fluidized bed combustor heat exchangers and internals; high speed furnace fans, galvanizing bath hardware and brazing fixtures; and high-temperature rotary calciners and kilns. There are also additional uses in the chemical/petrochemical process and pulp and paper industries.
Oxidation in Air - Excellent at 2000°F (1095°C)
Sulfidation - Second only to Co-base alloys
Molten Chloride Salts - Equal to alloy X
Chlorination - Very good to 1650°F (900°C)
Carburization - Equal to alloy 800H
Molten Zinc - Best Available