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
New Invar Sizes in Plate and Bar Please Call +44 (0)1268 774261
Maximum % Unless Noted
Modulus of elasticity at 20°C
Thermal coductivity at 20°C
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.
Tensile Strengths for Plate
63 (430) max
Tensile Strengths for Strip and Sheet
85 max (586)
86 min (593)
105 min (724)
Tensile Strengths for rod and Wire
85 (586) max
85 (586) max
86 (593) min
86 (593) min
111 (765) max
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