Invar 36 Manufacturer and Supplier

Invar 36 is a nickel-iron, low expansion alloy that exhibits a near zero rate of thermal expansion and is able to maintain almost constant dimensions from cryogenic temperatures to 260°C. It has become a popular choice when it comes to composite material manufacturing.

Invar 36 Mechanical Properties

Metallurgical Condition       Annealed, Descaled     

Yield Strength       KSI (MPa)       38 (260) Max

Tensile Strength    KSI (MPa)       63 (430) Max

Hardness HB   135

Elongation     50mm     >30% (Typical 40%)

Invar 36 Chemistry

Nickel     Ni    35.5 - 36.5

Iron Fe    Balance

Carbon   C     0.01 max

Silicon     Si     0.2 max

Manganese    Mn  0.2 - 0.4

Sulphur  S     0.002 max

Phosphorus   P     0.07 max

Chromium     Cr    0.15 max

Cobalt    Co   0.5 max

Invar 36 Physical Properties

Co-efficient of Thermal Expansion            

20-100°C       10-6/°C  0.8 - 1.7

20-200°C       10-6/°C  2.2 – 2.9

Density   g/cm³     8.13

Curie Temp    °F    446, °C    230

Melting Point °F    2462, °C    1450

Modulus of Elasticity at 20°C       MPa 145000

Youngs / Shears Modulus    MPa 57000

Specific Heat at 20°C    J/g- °C   0.51

Thermal Conductivity at 20°C     J/cm.s.°C 0.105

Poisson's coefficient            0.25

A Popular, Low Expansion Alloy

Invar 36 was discovered in 1896, by Charles Edouard Gullaume whilst working with the international Bureau of Weights and Measures. Its unique property of low and linear expansion over a wide temperature range allowed the production of effective bimetals which could be used in safety cut-off devices for gas cookers and heaters.For his work on the nickel-iron system and the discovery of Invar, Charles Edouard Guillaume was awarded a Nobel Prize for Physics early in the 20th century.