Duplex stainless steels are a family of grades combining good corrosion resistance with highstrength and ease of fabrication. Their physical properties are between those of the austenitic and ferritic stainless steels but tend to be closer tothose of the ferritics and to carbon steel. The chloride pitting and crevice corrosion resistanceof the duplex stainless steels is a function ofchromium, molybdenum, and nitrogen content. Itmay be similar to that of Type 316 or range up tothat of the sea water stainless steels such as the6% Mo austenitics. All the duplex stainless steels have chloride stress corrosion cracking resistance significantly greater than that of the 300-series austenitics. They all provide significantly greater strength than the austenitic grades while exhibiting good ductility and toughness