austenite, solid solution of carbon and other constituents in a particular form of iron known as γ (gamma) iron. This is a face-centred cubic structure formed when iron is heated above 910° C (1,670° F); gamma iron becomes unstable at temperatures above 1,390° C (2,530° F). Austenite is an ingredient of a kind of stainless steel used for making cutlery, hospital and food-service equipment, and tableware.