Deriving the Duplex name from the presence of both Austenite and Ferrite in similar proportions, Duplex Stainless Steels combine excellent corrosion resistance with high strength. The typical mechanical properties would be double that of a single phase austenitic grade such as 316, while, for example, offering superior stress corrosion cracking resistance in chloride solutions.
Standard Duplex Stainless Steels typically have a 22% Chromium and 5% Nickel and in the 1960's Langley Alloys developed the first 25% Chromium Duplex alloy, Ferralium 255, and coined the phrase Super Duplex.
