Hastelloy is the brand name of a range of specialised, high performance alloys manufactured by Haynes International. The primary component of Hastelloy is nickel, which is combined in varying degrees with other elements, such as chromium, molybdenum, iron, copper, manganese, cobalt, carbon, tungsten, aluminium and zirconium. There are currently 22 different types of Hastelloy.
All Hastelloy products perform well in corrosive environments, but are modified to excel in specialised applications. The following explains some of the unique properties of the most commonly used Hastelloys:
Hastelloy C-276 – A nickel-molybdenum-chromium alloy that performs well in most corrosive environments.
Hastelloy C-4 – Along with its anti-corrosion properties, Hastelloy C-4 is suited to high temperature applications.
Hastelloy B-3 – A nickel-molybdenum alloy that is highly effective in industrial applications involving the use of hydrochloric acid.
Hastelloy X – Made from nickel, chromium, iron and molybdenum, this alloy was developed for the petrochemical industries, combining oxidative resistance with good performance under high temperatures.
Hastelloy G – Excellent anti-corrosion properties against both oxidative and reducing media. This alloy is unique in that it is effective against both alkaline and acid corrosion.
All forms of Hastelloy are manufactured using standard alloy production techniques, depending on the format in which it is required. Hastelloy has good formability and can be manufactured as foil, rod, strips, blocks, plates and piping.
As well as being ideal for corrosive environments, the Hastelloy super-alloys offer a business advantage, in that they are known for their superior cost to performance ratio and are used for:
- Chemical applications
- Nuclear reactors
- Distillation equipment
- Petrochemical industry
- Paper production
- Waste treatment plants
During the 60s, a low chromium, nickel-molybdenum alloy was used in an experimental molten-salt nuclear reactor. Known as Hastelloy-N, it was specially developed to be compatible with the fluoride salts used in the reactor.
Chemical Composition of Inconel 625
|Mo||15 – 17 %|
|Cr||14.5 – 16.5 %|
|Fe||4 – 7 %|
|W||3 – 4.5 %|
Typical Properties of C-276
|Density||8.89 g/cm3||0.321 lb/in3|
|Melting point||1370 °C||2500 °F|
|Co-Efficient of Expansion||11.2 μm/m.°C
|Modulus of Rigidity||78.6 kN/mm2||11400 ksi|
|Modulus of Elasticity||205.5 kN/mm2||29806 ksi|