Duplex S31803 & S32205
Super Duplex S32750 & S32760

6% Molybdenum Stainless Steels
6 Moly S31254, 6 Moly N08925, 6 Moly N08926
Inconel & Titanium Grades 1, 2, 5, 7, 9 & 12
Stainless Steel & Nickel Alloys

Seamless & Welded Tubing
Seamless & Welded Pipe
Alloy Pipe Fittings,
Alloy Flanges, Alloy Valves

Round Bar, Plate/Sheet
Specialty Forgings

Specializing in ON TIME delivery of Super Duplex, Duplex, Titanium, 254SMO and Nickel Alloys
When you need an alloy now, call Alloys Now. 863-607-6119 sales@alloys-now.com

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Duplex Stainless Steel

UNS S31803 - UNS S32205

Duplex Plate/Sheet
Duplex Seamless & Welded Tube
Duplex Seamless & Welded Pipe
Duplex Round Bar
Duplex Flanges F51
Duplex Specialty Forgings
Duplex Seamless & Welded BW Fittings

Allows Now offers a large variety of products in Duplex Stainless Steel alloys such as tubing, seamless- and welded pipe, butt weld fittings, flanges, round bar and plate products:

Duplex Stainless Steels
Ferritic Austenitic
UNS S31803    UNS S32205

1/16" - 2" OD 0.016" - 0.250" WT
3 mm - 50 mm OD 0.5 mm - 6.0 mm WT
1/2" - 6" OD 0.035" - 0.500" WT
12 mm - 150 mm OD 1.0 mm - 12.0 mm WT
Seamless & Welded
1/2" - 36" Sch 10S thru Sch XXS
Butt Weld Fittings
Seamless & Welded
1/2" - 36" Sch 10S thru Sch XXS
WN & Blind
1/2" - 36" Sch 10S thru Sch XXS
150lbs thru 2500lbs
Round Bar 1/2" - 12"
Plate 1/8" - 3" thick

Called duplex because of its mixed microstructure with about equal proportions of ferrite and austenite, duplex stainless steels are a family of grades, which range in corrosion performance depending on their alloy content.

  • High strength
  • A cost-effective alternative to austenitic stainless steel 316L.
  • 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 weldability,
  • High energy absorption.
  • 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.

UNS S31803
Carbon Chromium Manganese Molybdenum Nitrogen Nickel Phosphorus Sulfur Silicon
0.030 max 21.0-23.0 2.00 max 2.50-3.50 0.08-0.20 4.50-6.50 0.030 max 0.020 max 1.00 max

UNS S32205
Carbon Chromium Manganese Molybdenum Nitrogen Nickel Phosphorus Sulfur Silicon
0.030 max 22.0-23.0 2.00 max 3.00-3.50 0.14-0.20 4.50-6.50 0.030 max 0.020 max 1.00 max

Trade Name UNS 6Moly Industry Specifications Chemical Composition Min.Tensile
SAF 2205 UNS S31803 ASME SA-182 (F51), SA-240, SA-798, SA-790, SA-815
ASTM A240, A276, A479, A789, A790, A815, A923, A928, A988
SAE J405
C 0.30 max
Mn 2.00 max
Mo 2.50-3.50
N 0.08-0.20
Ni 4.50-6.50
P 0.030 max
S 0.020 max
Si 1.00 max
90 65 25
SAF 2205 UNS S32205 ASTM A240, A240M, A276, A479, A480, A480M, A798, A7901, A815, A923, A928, A988
C 0.30 max
Cr 22.0-23.0
Mn 2.00 max
Mo 3.00-3.50
N 0.14-0.20
Ni 4.50-6.50
P 0.030 max
S 0.020 max
Si 1.00 max
 90 65 25

General Duplex stainless steel information

2205 is the most widely used duplex (ferritic/austenitic) stainless steel grade. It finds applications due to both excellent corrosion resistance and high strength. The standard duplex S31803 composition has over the years been refined by many steel suppliers, and the resulting restricted composition range was endorsed as UNS S32205 in 1996. Duplex S32205 gives better guaranteed corrosion resistance, but for much of the Duplex S31803 currently produced also complies with Duplex S32205. 2205 is not generally suitable for use at temperatures above 300ºC as it suffers from precipitation of brittle micro-constituents, nor below -50ºC because of its ductile-to-brittle-transition.

Duplex Applications

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.

Duplex Corrosion Resistance

Excellent general corrosion resistance; superior to Grade 316 in most environments. Excellent resistance to localized corrosion including intergranular, pitting and crevice corrosion; the CPT of 2205 is generally at least 35ºC. The grade is also resistant to chloride stress corrosion cracking (SCC) at temperatures of up to about 150ºC. Grade 2205 will often perform well in environments which cause premature failure of austenitic grades. It has better resistance to sea water then Grade 316.

Duplex Heat Resistance

Although 2205 has good high temperature oxidation resistance, this grade - like other duplex stainless steels - suffers from embrittlement if held for even short times at temperatures above 300ºC. If embrittled, this can only be rectified by a full solution annealing treatment. Duplex stainless steels are almost never used above 300ºC.
Duplex Heat Treatment

Duplex Heat Treatment

Solution treatment (annealing) - heat to 1020ºC-1100ºC and cool rapidly. This grade cannot be hardened by thermal treatment, but does work harden.

Source: Atlas Steels Australia