NITRONIC Alloys are classified into the 200 and 300 series and contain between 16% and 30% chromium and 2% to 20% nickel for enhanced surface quality, formability, corrosion, and wear resistance. Hardening austenitic alloys by heat treatment is not possible. These steels are the most widely used grades of stainless steel due to their superior formability and corrosion resistance. All austenitic steels are nonmagnetic in their annealed state. Certain austenitics, depending on their composition, are slightly magnetic when cold worked.