Invar 36 / Alloy 36

Invar 36® (Alloy 36)  is a 36% nickel-iron alloy that exhibits a near zero rate of thermal expansion which is roughly one tenth the expansion rate of carbon steel at temperatures from around -100°C up to 200°C. Along with this very low coefficient of linear thermal expansion over a broad range of temperatures, up to around 200 °C. Invar 36 retains superior strength and toughness at cryogenic temperatures, making it suitable for a variety of low temperature applications. Invar 36 is Available from stock in the flowing specifications ASTM F-1684, UNS K93603, UNS K93050

Typical Chemistry

Maximum % Unless Noted
Nickel, nominal Ni3636
CarbonC0.05 max0.15 max
ManganeseMn0.6 max1.00 max
SulfurS0.015 max0.020 max
PhosphorusP0.015 max0.020 max
Chromium Cr0.25 max0.25 max
CobaltCo0.50 max 0.50 max
SiliconSi0.40 max0.35 max

Physical Properties

Curie Temp°F446
Melting Point°F2600
Modulus of elasticity at 20°CMPa145000
Shears ModulusMPa57000
Specific HeatJ/g- °C0.51
Thermal coductivity at 20°CJ/cm.s.°C0.105

Invar 36 is available in two variations. One is the conventional Invar alloy, used generally for its optimum low expansion properties. The second is a variation of the basic alloy known as Free-Cut Invar 36® alloy (UNS K93050). This alloy has shown improved machinability for applications where high productivity is important. It is also a 36% nickel-iron alloy, but with a small addition of selenium to enhance machinability. For UNS No. K93603 and K93050, the iron, and nickel requirements are nominal, while for UNS No. K93500, the iron, nickel, and cobalt requirements are nominal. These levels may be adjusted by the manufacturer to meet the requirements for the coefficient of thermal expansion as specified in ASTM F1684. The total of aluminium, magnesium, titanium, and zirconium shall not exceed 0.20 %. The total of phosphorus and sulphur shall not exceed 0.025 %. Alloy 36 is available in a number of different forms such as pipe, tube, sheet, plate, round bar, forging stock, and wire. It is also important to note that Alloy 36 can be hot or cold worked, machined, and formed using the same processes as those used with austenitic stainless steel.

Alloy 36 CTE’s Graph

We also Offer Alloy 42 or Kovar which have lower CTE than Alloy Invar in this temperature range.

Stock Sizes 


Tensile Strengths for Plate

AnnealedKSI (MPa)63 (430) max

Tensile Strengths for Strip and Sheet

AnnealedKSI (MPa)85 max (586)
1/2 Hard KSI (MPa)86 min (593)
HardKSI (MPa)105 min (724)

Tensile Strengths for rod and Wire

AnnealedKSI (MPa)85 (586) max 85 (586) max
Cold WorkedKSI (MPa)86 (593) min 86 (593) min
UnannealedKSI (MPa)--------111 (765) max

Added Value

If you do not see the size or form of Invar that you require, please call or send us a mail, our Staff are very knowledgeable and will be able to help you. We can cut, slit, water jet, or center less grind Invar to your exact specifications.

Alloy 36 is also know by the following brand names

Nilo 36
Nickel Alloy 36
Pernifer 36

Common Applications

Some of our other Signature Alloys

Click on a product below to learn more…

Invar 36 is a Trademark Carpenter Technology Corp, Pernifer 36 is a Trademark of ThyseenKrupp-VDM, Germany, Invar is a Trademark of Imphy Alloys,  Nilo 36 is a Trademark Special Metals Corporation, USA