A steel that meets one of the following descriptions:

• Martensitic or Ferritic Chromium stainless steels containing more than 10 percent Chromium (typically AISI 400 series).
• Austenitic Chromium-Nickel stainless steels containing more than 16 percent Chromium and more than 6 percent Nickel (typically AISI 300 series).  This also includes the super austenitic stainless steels (with 6 percent Mo) and the alloys with nominally 20 percent Cr and 35 percent Ni such as Incoloy 825 or Alloy 20.
• Duplex Ferritic-austenitic stainless steels containing approximately 15–30 percent chromium and 2–8 percent Nickel (typically the 2205 and 2507 alloys).