ASTM A790 UNS S31803 Duplex Steel Seamless And Welded Pipe For Boiler
ASTM A790 is the standard specification for seamless and welded ferritic/austenitic stainless steel pipe. This specification covers piping intended for general corrosive and high-temperature service applications.
S31803 is the grade designation for a duplex stainless steel alloy under ASTM A790. It is also known as UNS S31803 or Duplex 2205. The "S" prefix indicates a stainless steel material, while "31803" is the Unified Numbering System (UNS) name for this specific alloy.
ASTM A790 S31803 is a specification covering seamless and welded ferritic/austenitic stainless steel pipe for general corrosive and high-temperature service. SA790 UNS S31803 pipe exhibits exceptional corrosion resistance in seawater and other chloride-rich environments. Its resistance to chloride-induced stress corrosion cracking makes it one of the most cost-effective long-term solutions available.
Duplex 31803 seamless pipe is suitable for high-sensitivity applications requiring precise measurements. However, compared to welded UNS S31803 pipe, the seamless characteristic slightly reduces its strength.
A790 S31803 DSS ERW pipe is used in applications including seawater and marine environments, chemical processing industries, food processing plants, heat generators, automotive components, boiler parts, and other high-temperature applications. Electric fusion welded (EFW) duplex S31803 UNS pipe can also be used interchangeably for less critical applications where slightly lower performance requirements are acceptable.
Chemical Composition of ASTM A790 S31803 pipe
| Grade | C | Mn | S | P | Si | Ni | Cr | Mo | N | |
| S31803 | Min | 4.5 | 21.0 | 2.5 | 0.08 | |||||
| Max | 0.03 | 2.0 | 0.02 | 0.03 | 1.0 | 6.5 | 23.0 | 3.5 | 0.20 |
Mechanical Properies of ASTM A790 S31803 seamless pipe
| Grade | Tensile Str Ksi(Mpa) | Yield Str Ksi(Mpa) | Elongation(%) | Brinell(HBW) | Rockwell C(HRC) |
| S31803 | ≥90(620) | ≥65(450) | ≥25 | ≥290 | ≥30 |
Wall Thickness Tolerance os ASTM A790
| OD Range | t/D Ratios | Wall Thickness Tolerance | |
| Under(-) | Over(+) | ||
| 1/8"~2 1/2" (Incl.) | All | 12.5% | 20% |
| 3"~18" (Incl.) | t/D up to 5% Incl. | 12.5% | 22.5% |
| >18" (Incl.) | t/D up > 5% Incl. | 12.5% | 15% |
| >18" Welded | All | 12.5% | 17.5% |
| >18" Seamless | t/D up to 5% Incl. | 12.5% | 22.5% |
| t/D up > 5% Incl. | 12.5% | 15% | |
If you have a project need for UNS S31803 stainless steel bright annealed tubing, we welcome your order. GNEE has a large inventory of popular products for you to choose from. We offer a variety of practical product forms, including seamless and welded. For detailed chemical composition and free samples, please contact our factory today. We offer competitive pricing and excellent service.
Duplex Steel S31803 Seamless Pipe Tube Specification
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Standard |
ASTM A790 / ASME SA790 UNS S31803, S32205, S32550, S32750, S32760 |
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Materials |
ASTM A815 – UNS S31803 |
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Size |
1/2"NB TO 12 "NB IN |
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Seamless Pipes & Tubes Sizes |
1/2" NB - 8" NB |
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Welded Pipes & Tubes Sizes |
6" NB - 24" NB |
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Thickness |
0.5-45mm |
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Outer Diameter |
6.0-630mm |
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Dimensions |
OD(6.0-630)*WT(0.5-45)mm |
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Schedule |
SCH20, SCH30, SCH40, STD, SCH80 |
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Type |
Welded / Fabricated / Seamless |
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Length |
Single Random, Double Random & Cut Length. |
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