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Invar 36

Global Supplier of Invar 36

City Special Metals are the UK’s leading stockist and supplier of high performance, specialist alloys including all varieties of Invar 36 (FeNi36).

Available in many forms we can offer a bespoke solution that meets your exact requirements and specification for your Invar 36 application, be it from Plate, Bar, Sheet, Coil or Wire. With over 20 years’ experience, our team has a combined wealth of knowledge about Invar 36 and its different characteristics, so we can guarantee you will find the product that fits your requirements.

For pricing or general advice speak to CSM today on +44 (0) 1268 774 261, email or alternatively complete the contact form below. 

Invar 36 Stockist Range

Product FormRange FromRange To
Invar Plate icon

Invar Plate

Invar Round Bar icon

Invar Round Bar

Invar Square Bar icon

Invar Square Bar

Invar Flat Bar icon

Invar Flat Bar

N/A250mm x 250mm
Invar Sheet & Coil icon

Invar Sheet & Coil

Invar Wire icon

Invar Wire


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Beneficial Properties

  • Dimensional Stability Between -100°C & 260°C
  • Durability Strong performance, toughness and resilience
  • Near zero Coefficient of linear thermal expansion
  • Flexibility Good workability, weldability and easy to machine

Markets & Applications

  • Moulds and lay up tools for composites
  • Devices, electrical transformers and circuit breakers
  • Precision equipment elements as such as: lasers, measuring and positioning devices, thermostats, precision condenser blades
  • High voltage transmission lines

Invar 36 Composition

Mechanical Properties

Metallurgical ConditionAnnealed, Descaled
Yield StrengthKSI (MPa)38 (260) Max
Tensile StrengthKSI (MPa)63 (430) Max
Elongation50mm>30% (Typical 40%)

Technical Specifications



NickelNi35.5 - 36.5
CarbonC0.01 max
SiliconSi0.2 max
ManganeseMn0.2 - 0.4
SulphurS0.002 max
PhosphorusP0.07 max
ChromiumCr0.15 max
CobaltCo0.5 max

Physical Properties

Co Efficient of Thermal Expansion
20-100°C10-6/°C0.8 - 1.7
20-200°C10-6/°C2.2 – 2.9
Curie Temp°F446
Melting Point°F2462
Modulus of Elasticity at 20°CMPa145000
Youngs / Shears ModulusMPa57000
Specific Heat at 20°CJ/g- °C0.51
Thermal Conductivity at 20°CJ/cm.s.°C0.105
Poisson's coefficient0.25

Invar 36 Information

Invar 36 (FeNi36) 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.

We offer a bespoke service so, if you don’t see the size or form that you require, contact us either by phone, email or our contact form below, and we will provide a solution to your requirements.

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.

If you'd like to know more about Invar 36's history and legendary status, read our blog article: "Invar - A Legend in Metals" which can be found in our insights area.

Invar is also known by the following trade names;

  • Invar ®
  • Invar 36 ®
  • Pernifer 36® 
  • Dilaton 36® 
  • Nilo 36® 
  • Ametek 936®
  • ATI 36®
  • NI 36®
  • FeNi36