What is Austenite?

Legal Definition
Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron, with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K (727°C); other alloys of steel have different eutectoid temperatures. The austenite allotrope exists at room temperature in stainless steel. It is named after Sir William Chandler Roberts-Austen (1843–1902).
-- Wikipedia
Legal Definition
Any iron that has carbon or facecentered crystaline structures. It is named after Sir W. C. Roberts Austen. Refer to martensite.