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Alloy 400 • UNS N04400 • WNR 2.436

Alloy 400 (UNS N04400) is a solid-solution 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 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 eat exchangers; and deaerating heaters.

Available tube product forms

Typical Applications

  • Heat exchangers
  • Steam Generators
  • Reboiler tubes
  • Nuclear core cooling tubes
  • Brine heaters and evaporator bodies in salt plant
  • Sulphuric and hydrofluric acid alkylation plant acids
  • Control lines

Typical manufacturing specifications

  • ASTM B163
  • ASTM B165
  • AMS 4574
  • BS3074

Industries predominantly using this grade

Technical Data

Mechanical Properties

Temper Annealed
Tensile Rm 70 ksi (min)
Tensile Rm 480  MPa (min)
R.p. 0.2% Yield 28 ksi (min)
R.p. 0.2% Yield 195 MPa (min)
Elongation (2” or 4D gl) 40 % (min)

Physical Properties (Room Temperature)

Specific Heat (0-100°C) 427°K-1
Thermal Conductivity 21.8 W.m -1.°K-1
Thermal Expansion 13.9 μm/μm/°C
Modulus Elasticity 173 GPa
Electrical Resistivity 5.47 μohm/cm
Density 8.83 g/cm3

Chemical Composition (% by weight)

Element Min Max
C - 0.3
Si - 0.5
Mn - 2
S - 0.24
Cu Balance
Fe - 2.5
Ni 63 70