Austenite

Work-Hardened Twinned Austenite

Austenite is a non-magnetic allotrope of Iron and other alloying elements, typically Chromium, Nickel, and Manganese.  Austenite is formed during heat treating, at temperatures above 1340*F, when the Iron undergoes a transition from the Body Centered Cubic System (BCC) to the Face Centered Cubic System (FCC), changing from Ferrite to Austenite.  Austenitic Steels have better corrosion resistance than carbon steels because of the high Chromium content, that reacts with the environment to  for a thin oxide layer that protects the surface of the metal from further exposure.