Duplex 2205 is a nitrogen-enhanced duplex stainless steel that was developed to combat common corrosion problems encountered with the 300 series stainless steels. Duplex ? describes a family of stainless steels that are neither fully austenitic, like 304 stainless, nor purely ferritic, like 430 stainless. The structure of 2205 duplex stainless steel consists of austenite pools surrounded by a continuous ferrite phase. In the annealed condition, 2205 contains approximately 40-50% ferrite. Often referred to as the work horse grade, 2205 is the most widely used grade in the duplex family of stainless steels The advantage of a duplex structure is that it combines the favorable qualities of a ferritic alloy (stress corrosion cracking resistance and high strength) with those of an austenitic alloy (ease of fabrication and corrosion resistance). Usage of 2205 Duplex stainless steel should be limited to temperatures below 600 F. Extended elevated temperature exposure can embrittle 2205 stainless.