Duplex Steel

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Duplex Steel

Duplex steel is a high-performance stainless steel that combines the excellent corrosion resistance of austenitic grades with the superior strength of ferritic grades. Its dual-phase microstructure provides outstanding resistance to stress corrosion cracking, pitting, and crevice corrosion, while delivering exceptional mechanical strength and toughness. Duplex steel is widely used in industries that require reliability in extreme environments, such as offshore, chemical processing, marine, and oil & gas sectors.

Duplex Steel Products and their Grades

Product Grades
Refractory Anchors ASTM A182 F51, ASTM A182 F53, ASTM A182 F55, ASTM A182 F61, ASTM A182 F54, ASTM A182 F60, ASTM A182 F70
Pipes A790
Tubes A789
Pipe Fitting A815
Forged Fitting A182 (F51, F53, F55, F61, F54, F60, F70)
Flanges A182 (F51, F53, F55, F61, F54, F60, F70)

Chemical Composition of Duplex Steel

Grade C (%) Mn (%) Si (%) P (%) S (%) Cr (%) Ni (%) Mo (%) N (%)
Duplex 2205 0.03 max 2.00 max 1.00 max 0.030 max 0.020 max 21.0 – 23.0 4.5 – 6.5 2.5 – 3.5 0.14 – 0.20
Duplex 2304 0.03 max 2.50 max 1.00 max 0.035 max 0.015 max 21.5 – 24.5 3.0 – 5.5 0.05 – 0.60 0.05 – 0.20
Duplex 329 0.08 max 1.00 max 1.00 max 0.040 max 0.030 max 23.0 – 28.0 2.5 – 5.0 1.0 – 2.0

Mechanical Properties of Duplex Steel

Grade Tensile Strength (MPa) Yield Strength (0.2% Proof) (MPa) Elongation (%) Hardness (Brinell HB)
Duplex 2205 620 min 450 min 25 min 290 max
Duplex 2304 600 min 400 min 25 min 290 max
Duplex 329 650 min 450 min 25 min 290 max

Applications of Duplex Steel

Duplex steel offers a unique combination of high strength, excellent corrosion resistance, and good weldability, making it ideal for use in challenging environments such as marine, chemical processing, and oil & gas industries.

Chemical Processing

Used in tanks, piping, and heat exchangers where resistance to chloride stress corrosion cracking is crucial.

Oil & Gas Industry

Ideal for subsea equipment, risers, and pipelines exposed to aggressive seawater and sour gas conditions.

Marine Engineering

Used for propeller shafts, offshore platforms, and seawater cooling systems due to high pitting resistance.

Desalination Plants

Applied in evaporators, pumps, and piping systems where saltwater corrosion is a major concern.

Power Generation

Used in heat recovery systems, condensers, and boilers for its excellent stress corrosion cracking resistance.

Pharmaceutical & Food Industry

Preferred for hygienic processing equipment due to its strength and ease of cleaning in corrosive conditions.