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Alloy 400

Last updated: August 17, 2017

What Does Alloy 400 Mean?

Alloy 400 is a solid solution alloy that can be hardened only by cold working. It exhibits great strength over a wide temperature range and shows excellent corrosion resistance.

The chemical composition of Alloy 400 is:

  • Nickel with addition of cobalt – 63%
  • Copper – 28 to 34%
  • Carbon – 0.3% max
  • Manganese – 2% max
  • Silicon – 0.5% max
  • Sulfur – 0.025% max
  • Iron – 2.5% max

Alloy 400 is also known as Monel 400.


Corrosionpedia Explains Alloy 400

Industrial nomenclature or the recommended grade for Alloy 400 is UNS N04400/ W.Nr. 2.4360 and 2.4361.

Alloy 400 exhibits excellent corrosion resistance to warm seawater and steam at high temperatures. This alloy resists stress corrosion cracking because of its high nickel content. The presence of copper also gives it resistance to sulfuric acid and other reducing agents in both extreme and mild temperature conditions. It also shows high resistance to alkalis.

Some of the major applications of grade 400 alloys include:

  • Marine engineering
  • Chemical and hydrocarbon processing equipment
  • Gasoline and freshwater tanks
  • Crude petroleum stills
  • De-aerating heaters
  • Boiler feed water heaters and other heat exchangers
  • Valves, pumps, shafts, fittings and fasteners
  • Industrial heat exchangers
  • Chlorinated solvents
  • Crude oil distillation towers


Monel 400

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