Steels that remain austenitic in structure (gamma iron) on slow cooling from the temperature of solidification. These steels exhibit no critical temperature on cooling. They cannot be hardened by heat treatment, although they may be cold work-hardened and annealed. Austenitic steels exhibit great shock strength, low elastic strength, and are very ductile.

They work harden very rapidly and develop great resistance to wear and abrasion. Outstanding examples are the manganese steels. The stainless austenitic steels are very resistant to corrosion.