Metallurgical and chemical processing performed in rotary calciners or reaction vessels can place severe demands upon process equipment. Temperatures at 1800ºF to 2000ºF (982ºC to 1093ºC), when combined with corrosive environments, can be a designer’s headache and a maintenance department’s nightmare. Designing strength into a vessel by using thick sections of stainless steel, or nickel alloys (such as No. 600), is not effective if high-temperature corrosion causes localized or even general wall thinning.
The answer? HAYNES® 556® alloy. 556 alloy is the one material which not only resists most forms of high-temperature corrosion, but also provides a strength advantage over stainless steel or nickel alloys. That can mean years of additional service life.
556 alloy offers still another opportunity. Take advantage of the increased strength by designing with thinner sections. This can mean increased process efficiency, significantly longer vessel service life, and upfront material costs still comparable to those for thicker-section nickel alloy construction.
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 used for service at elevated-temperatures in moderately to severely corrosive environments. Applications include tubing and structural members in waste heat recuperators, super heaters, 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 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