Alloy 2205 (Plate) (UNS S32205 Duplex F60 (UNS31803 Duplex F51))

Alloy 2205 duplex stainless steel is an alloy developed from the initial Super Duplex Stainless Steel. It is supplied in the solution annealed condition. 

As a form of duplex stainless steel, alloy 2205 was designed as comprising 22% chromium, 3% molybdenum, and 5-6% nickel nitrogen. Alloy 2205 combines the desirable aspect of properties of both austenitic and ferritic grades. The high chromium, molybdenum and nitrogen mixture results in a Pitting Resistance Equivalent number (PREN) of 33-34, providing pitting and crevice corrosion resistance superior to Alloy 316L or Alloy 317L austenitic stainless steels in almost all corrosive media. 

As a result of its excellent corrosion properties, it is well-suited to environments containing chlorides and hydrogen sulphide, for use in oil and gas extraction from sour wells, in refineries and in process solutions contaminated with chlorides.

It also has good erosion fatigue properties as well as lower thermal expansion and higher thermal conductivity than austenitic steels. The yield strength is about twice that of austenitic stainless steels, allowing a designer to save weight and make the alloy more cost-competitive when compared to Alloy 316L or Alloy 317L.