Austenite (or gamma phase iron)'s a metallic non-magnetic solid solution of iron and an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K (about 727 °C); other alloys of steel have different eutectoid temperatures. It's named after Sir William Chandler Roberts-Austen (1843-1902). Behavior in Plain-Carbon Steel As austenite cools, it often transforms into a mixture of ferrite and cementite as the carbon diffuses. Depending on alloy c… (More on Austenite)