Inconel Superalloys

Inconel is a group of superalloys that are nickel-chromium-based austinites. Its alloys are commonly utilized in processes that require high temperature. In the 1940s, some Wiggin Alloys research teams in Hereford, England developed it for the creation of the Whittle jet engine.

There are many different types of inconels, and they vary in their compositions.  They all are predominantly made up of nickel as the first element, and chromium as the second. Some examples of other elements found in inconels are iron, molybdenum, manganese, aluminum, titanium, cobalt, sulfur, boron, phosphorus, copper, silicon, carbon, and niobium.

The following are the some examples of inconel alloys and their respective compositions:

  • Inconel 600 – made up of 72% Ni+Co, 14%-17% Cr, 6%-10% Fe, 0.15% C, 1% Mn, 0.015% S, 0.50% Si, and 0.50% Cu. It is utilized in nuclear engineering, food processing, aerospace, chemical industry, pulp and paper manufacture, and heat treatments.
  • Inconel 625 – made up of 58% Ni, 20%-23% Cr, 8%-10% Mo, 3.15%-4.15% Nb+Ta, and 5% Fe. It is good for welding and is resistant to acids.
  • Inconel 690 – made up of 27%-31% Cr, 7%-11% Fe, 0.50% Si, 0.50% Mn, 0.50% Cu, 0.50% Si, 0.05% C, 0.015% S, and the rest is Ni. It is widely used in various welding processes, nuclear and high temperature applications, and duct work.
  • Inconel 718 – made up of 50%-55% Ni+Co, 17%-21% Cr, 4.75%-5.5% Nb+Ta, 2.8%+3.3% Mo, 0.65%-1.15% Ti, and 0.2%-0.8% Al. It is typically employed in nuclear reactors, rocket motors, gas turbines, and spacecraft applications.
  • Inconel 722 – made up of 14%-17% Cr, 5%-9% Fe, 2%-2.75% Ti, 1% Mn, 0.5% Cu, 0.4%-1% Al, 0.01% S, 0.07% Si, 0.08% C, and the remainder is Ni. It is commonly used in the manufacture of turban section frames and other gas turbine materials.
  • Inconel 751 – made up of 70% Ni, 14%-17% Cr, 5%-9% Fe, 2.2%-6% Ti, 1% Mn, 0.90%-1.5% Al, 0.70%-1.2% Nb, 0.50% Cu, 0.50% Si, 0.10% C, and 0.01% S. It can be welded, formed, forged, cold worked, hot worked, or annealed to be useful in diesel engines, exhaust valves, and other processes.
  • Inconel 825 – made up of 38%-46% Ni, 22% Fe, 19.5%-23.5% Cr, 2.5%-3.5% Mo, 1.5% Cu, and 0.6%-1.2% Ti. It is frequently used in chemical applications, nuclear fuel reprocessing, pickling equipment, and acid production.
  • Inconel 901 – made up of 41%-43.5% Ni, 11%-14% Cr, 2.2%-2.75% Ti, 1% Si, 9.8% Mn, 0.5% Cu, 0.35% Al, 0.1% C, 0.04% P, 0.04% S, 0.01%-0.02% B, and the rest is Fe. It is used in high temperature and stress applications.