Introduction:
Hastelloy is the
registered trademark name of Haynes International, Inc. The trademark is
applied as the prefix name of a range of twenty-two different highly
corrosion-resistant metal alloys, loosely grouped by the metallurgical industry
under the material term “superalloys” or “high-performance alloys”.
The predominant
alloying ingredient is typically the transition metal nickel. Other alloying
ingredients are added to nickel in each of the subcategories of this trademark
designation and include varying percentages of the elements molybdenum,
chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum,
carbon, and tungsten.
The primary
function of the Hastelloy super alloys is that of effective survival under
high-temperature, high-stress service in a moderately to severely corrosive,
and/or erosion-prone environment where more common and less expensive
iron-based alloys would fail, including the pressure vessels of some nuclear
reactors, chemical reactors, distillation equipment, and pipes and valves in
chemical industry. Although a super alloy, Hastelloy does experience
degradation due to fabricating and handling. Electropolishing or passivation of
Hastelloy can improve corrosion resistance.
