1.4462, X2CrNiMoN22-5-3, Duplex Stainless Steel

Introduce

1.4462 stainless steel is the most widely used duplex stainless steel grade. Its high chromium and molybdenum content gives the stainless steel excellent corrosion resistance. The microstructure provides resistance to stress corrosion cracking and ensures high strength.

Applications

DIN 1.4462 is typically used in the construction of heat exchangers, pressure vessels, tanks, tubes and pipes for the following industry areas:

 * Chemical processing, transport and storage.

 * Oil and gas exploration and processing equipment.

 * Marine and other high chloride environments.

 * Pulp and paper digesters, liquor tanks and paper machines.

Standard

    EN 10088-2: 2005 Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes

    EN 10088-3: 2005 Stainless steels. Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes

EN 10028-7: 2007 Flat products made of steels for pressure purposes. Stainless steels

Chemical Component

Mechanical Properties

Corrosion Resistance

 Due to its high chromium, molybdenum, and nitrogen content, Duplex 1.4462 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 1.4462 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 1.4462 is therefore not recommended for use above 572°F (300°C)

Heat Treatment

 Annealing temperature range is 1868 to 2012°F (1020 to 1100°C)

 Cannot be hardened by heat treatment – but Duplex 1.4462 does work-harden

 Special consideration is needed to compensate for a higher coefficient of thermal expansion to avoid warping and distortion

Hot Forming

Most Duplex 1.4462 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.

Cold Forming

Duplex 1.4462 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.

Machinability

Duplex 1.4462 is somewhat more difficult to machine than the 300 series austenitic stainless steels. Higher cutting forces are required and more rapid tool wear is typical. Some guidelines for machining are:

A) Use powerful, rigid machines with extremely strong rigid mounting of tools and work piece,

B) Minimize vibration by keeping the tool extension as short as possible,

C) Use a nose radius on the tool, no longer than necessary, for carbides that have a sharp edge while still providing adequate strength,

D) Design machining sequences to always provide for a depth of cut below the work hardened layer resulting from the previous passes.