Duplex stainless steels are two-phase alloys, consisting of approximately equal parts austenite and ferrite. In addition to chromium in the range of 20 to 30%, these alloys contain molybdenum, nitrogen, and other elements providing increased resistance to pitting and crevice corrosion. Therefore they are commonly used in high chloride environments. The higher alloys in this family are often referred to as Super Duplex. The duplex microstructure and nitrogen also provide strength. In the annealed conditions, these alloys have yield strengths between 65 and 100 KSI. In the cold hardened condition, yield strength as high as 160 KSI may be achieved.