Duplex is a material having an approximate equal amount of austenite and ferrite. These combine excellent corrosion resistance with high strength. Mechanical properties are approximately double those of singular austenitic steel and resistance to stress corrosion cracking is superior to type 316 stainless steel in chloride solutions.
Duplex material has a ductile / brittle transition at approximately -50°C. High temperature use is usually restricted to a maximum temperature of 300°C for indefinite use due to embrittlement