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