As a nickel-copper alloy, alloy 400 has excellent corrosion resistance in a wide variety of media. This alloy is highly resistant to sea water and steam at high temperatures as well as to salt and caustic solutions. Alloy 400 is characterized by its general corrosion resistance, good weldability, and moderate to high strength in the tempered conditions.

This alloy has excellent resistance to rapidly flowing and warm seawater, brackish water, and steam. It is particularly resistant to hydrochloric and hydrofluoric acids when they are de-aerated. This alloy is slightly magnetic at room temperature. Alloy 400 is widely used in the chemical, oil, and marine engineering industries.