Duplex 2205 is a two-phase, ferritic, austenitic 22% chromium, 3% molybdenum, 5 to 6% nickel alloyed stainless steel. It is the most widely used duplex stainless steel grade and is characterized by high yield strength, double that of the standard austenitic stainless steel grades. It also demonstrates good fatigue strength, as well as outstanding resistance to stress corrosion cracking, crevice, pitting, erosion, and general corrosion in severe environments.

Corrosion Resistance

Due to its high chromium, molybdenum, and nitrogen content, Duplex 2205 demonstrates superior corrosion resistant properties to 316 and 316L in most environments

Chromium, molybdenum, and nitrogen content also provide high resistance to pitting and crevice corrosion, even in oxidizing and acidic solutions

Resistant to chloride stress corrosion cracking and temperatures of up to about 302°F (150°C)

The presence of ferrite provides for good performance of Duplex 2205 in caustic environments

Heat Resistance

Similar to other duplex stainless steels, Duplex 2205 has good oxidation resistance at high temperatures

Subject to embrittlement when exposed to temperatures above 572°F (300°C) even when exposed for short periods of time; Duplex 2205 is therefore not recommended for use above 572°F (300°C)

Processing – Hot Forming

Most Duplex 2205 producers recommend a maximum hot forming temperature between 2010 and 2100°F (1100 to 1150°C). If the shape of the work piece is not compact, the edges may be significantly cooler than the bulk, and there is risk of cracking in the cooler regions.

Processing – Cold Forming

Duplex 2205 has shown good formability in a variety of fabrications. The high strength of Duplex 2205 can pose problems. Even when the equipment has sufficient power, allowance must be made for higher spring-back caused by the grade’s high strength.

Applications

● Chemical processing, transport and storage – pressure vessels, tanks, piping, and heat exchangers

● Oil and gas exploration and processing equipment – piping, tubing, and heat exchangers

● Marine and other high chloride environments

● Effluent scrubbing systems

● Pulp and paper industry – digesters, bleaching equipment, and stock-handling systems

● Cargo tanks for ships and trucks

● Food processing equipment

● Biofuels plants