HASTELLOY is the registered trademark name of Haynes International, Inc. The trademark is applied as the prefix name of a range of roughly fifteen different highly corrosion resistant metal alloys loosely grouped by the metallurgical industry under the material term “super alloys” or "high performance alloys". A trademark (Commonwealth English: trade mark)[1] is a distinctive sign of some kind which is used by a business to identify itself and its products or services to consumers, and to set the business and its products or services apart from those of other businesses. ... An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ... Metallurgy is a domain of materials science and of materials engineering that studies the physical and chemical behavior of metallic elements and their mixtures, which are called alloys. ...

The predominant alloying ingredient is typically the transition metal nickel. Other alloying ingredients are added to the nickel in each of the sub categories of this trade mark designation and include varying percentages of the elements molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminum, carbon, and tungsten. General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10 , 4, d Density, Hardness 8908 kg/m³, 4. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metal Group, Period, Block 6 (VIB), 5, d Density, Hardness 10280 kg/m3, 5. ... General Name, Symbol, Number cobalt, Co, 27 Chemical series transition metals Group, Period, Block 9 , 4, d Density, Hardness 8. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11 , 4, d Density, Hardness 8920 kg/m3, 3. ...

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.