S32205 Tubing/Piping Duplex S32205 is a nitrogen enhanced duplex stainless steel that was developed to combat common corrosion problems encountered with the 300 series stainless steel. “Duplex” describes a family of stainless steel that are neither fully austenitic, like 304 stainless, nor purely ferritic, like 430 stainless steel. The structure of 2205 duplex stainless steel consists of austenitic pools surrounded by a continuous ferritic phase. In the annealing condition, 2205 contains approximately 40-50% ferrite. Ofen referred to as the work horse grade, 2205 is the most widely used grade in the duplex stainless steel tube. S32205 Chemical composition, % according to ASTM A789 ASTM A790 C Si Mn P S Cr Mo Ni N Cu Min 22.0 3.0 4.50 0.14 Max 0.03 1.00 2.00 0.030 0.02 23.0 3.50 6.50 0.20