Stainless Steel Duplex Grades
North American Stainless produces duplex grades 2205 and 2304 in both flat products and long products. Type 2205 and 2304 are duplex stainless steel grades with a microstructure, when heat treated properly, of nearly equal proportions of austenite and ferrite.
The higher chromium, molybdenum and nitrogen contents give 2205 significantly improved pitting and crevice corrosion resistance in the presence of chlorides. 2304, also called lean duplex, exhibits excellent pitting and crevice corrosion resistance. These grades exhibit better corrosion resistance than 316 SS in high pH and in presence of the chlorides, making these very suitable for use as rebar for bridge constructions in colder areas to resist road salt.
2205 is a highly suitable material for service in environments containing chlorides and hydrogen sulfide such as marine environments and the oil and gas extraction and processing industries. Typical applications also include the chemical industry, the pulp and paper industry and the mining industry.