Download

Alloy 400

Alloy 400, UNS N04400, W.Nr.2.4360, 2.4361

Alloy 400 is a single-phase, solid solution, nickel-copper alloy that can be hardened only by cold working. It has high strength and toughness over a wide temperature range and excellent resistance to many corrosive environments.

Alloy 400 is characterized by:

Resistance against chloride-induced stress corrosion

Excellent strength even at low application temperatures

Easy processing compared to other high-alloy materials

Approved for pressure vessels from -10 to 425°C (14 to 797°F) pursuant to VdTÜV Material Sheet 263 and up to 480°C (896°F) in accordance with ASME Boiler and Pressure Vessel Code. 

Alloy 400 is widely used in many fields, especially marine and chemical processing. Typical applications are valves and pumps; pump and propeller shafts; marine fixtures and fasteners; electrical and electronic components; springs; chemical processing equipment; gasoline and fresh water tanks; crude petroleum stills, process vessels and piping; boiler feedwater heaters and other heat exchangers; and deaerating heaters.

Alloy 400 in annealed condition as per ASTM B165

Alloy 400 has excellent resistance to neutral and alkaline salts and has long been the standard material for salt production systems. Alloy 400 is one of the few materials which can be used in contact with fluorine, hydrofluoric acid and hydrogen fluoride or their compounds. The material has a very high resistance to alkaline media. Its behavior in seawater is also excellent compared to copper-based alloys with an increased resistance to cavitation. Alloy 400 can be used in contact with highly diluted mineral acids, such as sulfuric and hydrochloric acid, provided that they are not ventilated.

Since the alloy does not contain chromium, the corrosion rates can increase significantly under oxidizing conditions. While Alloy 400 is resistant to stress corrosion cracking, it can display stress cracks in the presence of mercury or in moist, aerated HF vapors. Stress relief annealing is necessary in these conditions.

Alloy 400 exhibits resistance to corrosion by many reducing media. It is also generally more resistant to attack by oxidizing media than higher copper alloys. This versatility makes alloy 400 suitable for service in a variety of environments.

Alloy 400 is widely used in marine applications. While alloy 400 products exhibit very low corrosion rates in flowing seawater, stagnant conditions have been shown to induce crevice and pitting corrosion. Alloy 400 is also resistant to stress corrosion cracking and pitting in most fresh and industrial waters.

Alloy 400 offers exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point. It is perhaps the most resistant of all commonly used engineering alloys. Alloy 400 is also resistant to many forms of sulfuric and hydrochloric acids under reducing conditions.

(1) Hot formed, annealed, descaled

(2) Cold worked and bright annealed

(3) Cold worked, bright annealed, polished (MP, EP, CP etc.)

Chemical composition

Tension

Hardness

Flaring

Flange

Flattening

Micro structure

Hydrostatic

NDT

Intergranular Corrosion

Surface condition

Shape and dimension

Positive Material Identification