Super Invar® 32-5
CarTech® Super Invar 32-5 (UNS K93500) is an austenitic, magnetic iron-nickel-cobalt alloy with a chemistry consisting of 32% nominal nickel, 5% cobalt max. and balance iron. Super Invar 32-5 is sometimes referred to as Invar 32-5 or Nickel 32-5 Alloy.
Super Invar is manufactured to provide minimum thermal expansion at room temperatures. The thermal expansion rates exhibited by this alloy is less than half of Invar 36 with a narrower application temperature range due to a lower Curie temperature. The alloy exhibits austenite stability to service temperatures at least -67°F (-55°C). ASTM F1684 and UNS K93500 are the specification references.
Although Super Invar has a substantially lower expansivity than Invar, it is susceptible to martensite transformation in the vicinity of -30°C. (-22°F), due to its reduced nickel content.
Super Invar has a very low coefficient of thermal expansion at temperatures from below -50°C. (-58°F.) up to about 100°C. (212°F.). It also exhibits thermal stability, a martensitic transformation inception point which is controlled, so as to fall well below the lowest temperature to be encountered in the particular application.
