What is invar36?
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
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.
What is Invar used for?
high-grade Invar 36 material for a wide range of industries where dimensional changes due to temperature variation must be minimized, some of the applications where UNS K93600 is utilized include:
- Aircraft controls
- Optical & laser systems
- Radio & electronic devices
- Composite forming tools & dies
- Cryogenic components
Invar 36® Material Advantages
Invar 36 can be hot and cold formed and machined using processes like austenitic stainless steels and is also weldable using Filler Metal CF26. Some of the other benefits associated with the use of Invar nickel alloy 36 include:
- Superior dimensional stability
- Numerous workability aspects
- Extremely low coefficient of thermal expansion (CTE)