Duplex & Super Duplex

2205 Duplex

A widely used duplex steel combining high strength and corrosion resistance in various organic acids, anorganic acids, aggressive coolingwaters and hydrous H2S/NaCl mixtures. With a near equal mix of austenite and ferrite, they give yield strength 30% higher and tensile strengths marginally higher than comparable nitrogen-containing austenitics. High resistance to general corrosion and specifically to pitting and crevice corrosion. Their resistance to stress-corrosion cracking in neutral chlorides is superior to that of the austenites.

2507 Super Duplex

UNS S32750 (2507) is a super ferritic-austenitic grade with high mechanical properties and superior corrosion resistance. Besides the ferritic-austenitic structure, 2507 has an excellent resistance to pitting and crevice corrosion and is therefore particularly suitable for sea water applications and for process systems on off-shore platforms, respectively in all situations where there is a risk of stress corrosion. The high tensile properties are twice comparing with TP 316 L stainless steel.

Characteristics

Duplex alloys are essentially a compromise possessing some of the ferritic stress corrosion cracking resistance and much of the superior formability of the common austenitic stainless alloys, at a cost saving over the high nickel alloys.
With its high level of chromium, Super-Duplex steel provides outstanding resistance to acids, acid chlorides, caustic solutions and other environments in the chemical/petrochemical, pulp and paper industries, often replacing 300 series stainless steel, high nickel super-austenitic steels and nickel-based alloys.

Composition of Duplex Stainless Steels grades we provide :-

Material

UNS no.

Werkst.
Nr.

C
Max

Mn
Max

P
Max

S
Max

Si
Max

Cr

Ni

Mo

Other elements

2205 Duplex

 S31803 1.4462 0.03 2.0 0.030 0.020 1.00 21-23 4.5 -
6.5		 2.5 -
3.5		 N=0.08-0.20

2507 S.Duplex

 S32750 1.4410 0.03 1.2 0.035 0.020 0.80 24-26 6-8 3-5 N=0.24-0.32,
Cu0.05max

S.Duplex

 S32760 1.4501 0.03 1.0 0.030 0.010 1.00 24-26 6-8 3-4 W=0.5-1.0,Cu=0.50 -
1.00,N=0.20-0.30

Benefits

  • High strength,
  • High resistance to pitting, crevice corrosion resistance.
  • High resistance to stress corrosion cracking, corrosion fatigue and erosion,
  • Good sulfide stress corrosion resistance,
  • Low thermal expansion and higher heat conductivity than austenitic steels,
  • Good workability and weld-ability,
  • High energy absorption.
  • High thermal conductivity
  • Low coefficient of thermal expansion

Applications

  • Heat exchangers, tubes and pipes for production and handling of gas and oil,
  • Heat exchangers and pipes in desalination plants,
  • Pressure vessels, pipes, tanks and heat exchangers for processing and transport of various
  • Chemicals,
  • Pressure vessels, tanks and pipes in process industries handling solutions containing chlorides,
  • Rotors, fans, shafts and press rolls where the high corrosion fatigue strength can be utilized,
  • Cargo tanks, piping and welding consumables for chemical tankers.
  • Mechanical and structural components,
  • Power industry FGD systems,
  • Pipes in process industries handling solutions containing chlorides,
  • High-strength, highly resistant wiring.
  • Paper and Pulp Industry.