Duplex s32205, s31803 is a nitrogen enhanced duplex stainless steel that was developed to combat common corrosion problems encountered with the 300 serious stainless steel. "duplex" describes a family of stainless steel that are neither fully austenitic, like 304 stainless, nor purely ferritic phase. In the annealing 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 stainless tube. As required