ASTM A790 UNS S31803 S32750 S32760 Duplex Stainless Steel Pipe

ASTM A790 UNS S31803 S32750 S32760 Duplex Stainless Steel Pipe


ASTM A790 UNS S31803, UNS S32750 and UNS S32760 are duplex ( Ferritic/Austenitic ) steel grades, with high chromium and molybdenum elements, UNS S31803 is the most wide used duplex stainless, it has excellent corrosion resistance, and high strength feature, generally S31803 stainless steel pipe is applied in corrosion and high temperature environment.

ASTM A790 Standard

ASTM A790 / A790M specification specify duplex welded and seamless steel pipe manufacturing, sizes, tolerances, testing condition.

The specification covers seamless and straight-seam welded ferritic/austenitic steel pipe for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. The pipe shall be made by the seamless or an automatic welding process, with no addition of filler metal in the welding operation. Heat analysis shall be made to determine the percentages of the elements specified. Tension tests, hardening tests, flattening tests, hydrostatic tests and nondestructive electric tests shall be made to conform to the specified requirements.

ASTM A790 UNS S31803 S32750 And S32760 Compositions

Duplex Stainless Steels are characterized by Austenitic stainless steels and Ferritic stainless steels, high chromium (18–30%) and molybdenum (up to 5%) and lower nickel contents (3% – 10%) than Austenitic stainless steels, there are Lean Duplex, Standard Duplex, Super Duplex and Hyper Duplex.

S32101LDX 21010.0401.004.0/6.00.0400.03021.0/22.00.10/0.801.35/1.70N 0.20/0.25; Cu 0.10/0.80
S32202DX 22020.0301.002.000.0400.01021.5/24.00.451.00/2.80N
S3220522050.0301.002.000.0300.02022.0/23.03.0/3.54.5/6.5N 0.14/0.20
S3230423040.0301.002.500.0400.03021.5/24.50.05/0.603.0/5.5N 0.05/0.20; Cu 0.05/0.60
S32404Uranus 500. 0.20; Cu 1.0/2.0
S32520Uranus 52N+0.0300.801.500.0350.02024.0/26.03.0/4.05.5/8.0N 0.20/0.35; Cu 0.50/2.00
S32550Ferralium 2550.041.001.500.0400.03024.0/27.02.9/3.94.5/6.5N 0.10/0.25; Cu 1.50/2.50
S3275025070.0300.801.200.0350.02024.0/26.03.0/5.06.0/8.0N 0.24/0.32; Cu 0.50
S32760Zeron 1000.0301.001.000.0300.01024.0/26.03.0/4.06.0/8.0N 0.20/0.30; Cu 0.5/1.00; W 0.50/1.00

Chemical Composition % By Mass Max, unless a range or minimum is indicated.

ASTM A790 UNS S31803 Duplex Stainless Steel Pipe

ASTM A790 standard state welded and seamless pipe dimensions conforming to ANSI B36.19, outside diameter range from to NPS 1/8 to NPS 30, pipe schedules have Sch 5S, SCH10S, SCH40S, and SCH80S, other pipe sizes can be offered on request.

Dimensional tolerances of ASTM A790 pipe should conform to ASTM A999 in outside and wall thickness, The pipe shall be pickled free of scale. When bright annealing is used, pickling is not necessary, DONGSHANG stainless supply A790 standard welded and seamless pipe with high quality, dimensional accuracy and excellent finish.

Duplex Stainless Steel Pipe Applications

Due to duplex stainless steel excellent corrosion resistance and high strength, duplex stainless steel pipe and tube are applied in harsh environments, even in chloride and sulphide environments.

Duplex stainless steel pipe are typically used in:

  • Chemical processing, transport and storage
  • Oil and gas exploration and offshore rigs
  • Oil and gas refining
  • Marine environments
  • Pollution control equipment
  • Pulp & paper manufacturing
  • Chemical process plant

Duplex Stainless Steel Features

Duplex stainless steels have Austenitic and Ferritic stainless steel microstructure, and possess properties in two groups stainless steel, however, there are different.

Versus Austenitic

  • Higher yield strength
  • Greater corrosion resistance
  • Stress corrosion cracking resistance
  • Not common, used temperate under 250 C.
  • Fabricability not good as Austenitic
  • Strictly control heat treatment and welding process
  • Price stability

Versus Ferritic

  • Good toughness than Ferric, not hard
  • Greater corrosion
  • Fabricability is better
  • Better weldability
  • Wide usage than Ferritic
  • Higher price

Corrosion Resistance

Duplex stainless steel are extremely corrosion resistant, including intergranular corrosion and stress corrosion cracking.

Heat Resistance

Duplex steel grades have a good performance in high temperature, and can be used down to at least -50°C low temperature, better ductility than the ferritic and martensitic grades.

Heat Treatment

Solution temperature is around 1100°C, and rapid cooling.

UNS DesignationTemperatureQuench
S318031870-2010 °F [1020-1100°C]Rapid Cooling In Air Or Water
S322051870-2010 °F [1020-1100°C]Rapid Cooling In Air Or Water
S315001800-1900 °F [980-1040°C]Rapid Cooling In Air Or Water
S325501900 °F [1040°C] Min.Rapid Cooling In Air Or Water
S312001920-2010 °F [1050-1100°C]Rapid Cooling In Water
S312601870-2010 °F [1020-1100°C]Rapid Cooling In Water
S320011800-1950 °F [982-1066°C]Rapid Cooling In Air Or Water
S320031850-2050 °F [1010-1120°C]Rapid Cooling In Air Or Water
S321011870 °F MinQuenched In Water Or Rapidly Cooling In Other Means
S322021870-1975 °F [1020-1080°C]Rapid Cooling In Air Or Water
S325061870-2050 °F [1020-1120°C]Rapid Cooling In Air Or Water
S323041700-1920 °F [925-1050°C]Rapid Cooling In Air Or Water
S327501880-2060 °F [1025-1125°C]Rapid Cooling In Air Or Water
S327602010-2085 °F [1100-1140°C]Rapid Cooling In Air Or Water
S329501820-1880 °F [990-1025°C]Rapid Cooling In Water
S325201975-2050 °F [1080-1120°C]Rapid Cooling In Air Or Water

Tensile And Hardness Requirements

GradeTensile Strength, Min., Ksi [MPa]Yield Strength, Min., Ksi [MPa]Elongation In 2 In., Or 50mm, Min, %Hardness, Max Brinell
S3180390 [620]65 [450]25290
S3220595 [655]70 [485]25290
S3150092 [630]64 [440]30290
S32550110 [760]80 [550]15297
S31200100 [690]65 [450]25280
S31260100 [690]65 [450]25290
S3200190 [620]65 [450]25290
S32304100 [690]65 [450]25290
S32750116 [800]80 [550]15310
S32760109 [750]80 [550]25300
S32950100 [690]70 [480]20290
S32520112 [770]80 [550]25310