

Duplex grades such as UNS S32205 are examples of equal amounts of austenitic and ferritic phases that provide good strength and corrosion resistance. Super Duplex has higher amounts of chromium and molybdenum which resist more aggressive chloride environments.
Selection based on operating conditions. Stainless is the average workhorse, Duplex handles chlorides, Inconel and Hastelloy handle extremes of heat and acids, Monel performs well in marine applications.
Hastelloy C276 is resistant to more oxidising and reducing acids than most alloys and is the preferred choice for aggressive chemical processing environments.
Duplex 2205 and Super Duplex bars are not susceptible to sour gas and chloride stress corrosion cracking, and Inconel 625 is used on high pressure, high-temperature wellhead components.
SS 316 has 2-3% of molybdenum content which gives it better resistance to chlorides and acids. SS 304 is less expensive and is good for general fabrication where there is no saltwater or chemical exposure.