ASTM A789 Tube

Duplex Stainless Steel Pipes

ASTM A789 Tube

Reliable Steel is a leading manufacturer and exporter of ASTM/ASME SA 789 Duplex Tubes in mostly countries. We offer best quality ASTM/ASME SA 789 Tubes which is most durable and cost-effective. We fabricated ASTM/ASME SA 789 Tubes in various sizes and lengths. Our Duplex ASTM/ASME SA 789 Tubes has magnetic property, yields strength, tensile strength, outstanding durability, high toughness, long-term working ability etc.

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Duplex A/SA-789 tubes are a type of stainless steel tubing that conforms to the ASTM A789/ASME SA789 standard, known for combining high strength with good corrosion resistance, especially against stress corrosion cracking. They are produced with a duplex (two-phase) microstructure of approximately 50% austenite and 50% ferrite and are used in demanding applications like chemical processing, food processing, and marine environments. Common grades include UNS S31803 and UNS S32205, while super duplex grades like UNS S32750 and S32760 offer even higher performance.
The Duplex A/SA A789 specification covers seamless and welded ferritic/austenitic stainless steel tubing intended for general corrosion resistance and, more specifically, resistance to stress corrosion cracking. Common grades include UNS S31803 (Alloy 2205) and the enhanced UNS S32205.


Key Features, Properties & Composition

  • Microstructure: Duplex structure with roughly 50% ferrite and 50% austenite.
  • Corrosion resistance: Excellent resistance to general and localized corrosion, with a particular focus on resisting stress corrosion cracking.
  • Strength: High tensile and yield strengths, often higher than standard austenitic stainless steels.
  • Chemical composition: Contains chromium, molybdenum, and nitrogen to enhance corrosion resistance.
  • Temperature limitations: Susceptible to embrittlement if used for prolonged periods at elevated temperatures, generally above 572° F (300° C). 

Properties

Property Value
Minimum Yield Strength 448 MPa (65 ksi)
Minimum Tensile Strength 621 MPa (90 ksi)
Minimum Elongation 25%
Density 7.8 g/cm³ (0.281 lb/in³)
Hardness (Brinell) 290 max

Chemical Composition

Chromium Nickel Molybdenum Nitrogen
22.0–23.0% 4.5–6.5% 3.0–3.5% 0.14–0.20%

Applications

  • Chemical process industry
  • Oil and gas industry
  • Marine environments and desalination plants
  • Food and beverage processing
  • Heat exchangers and condensers
  • General use in construction, automotive, and drilling equipment

Important Considerations

  • Heat Treatment: All A/SA A789 tubes must be furnished in a mandatory heat-treated condition (solution annealed and quenched) to achieve the specified mechanical properties and appropriate microstructure.
  • Temperature Limits: This material is susceptible to embrittlement if used for prolonged periods at elevated temperatures, with typical usage restricted to applications below 600°F (316°C).
  • Form: Available in round shape, including seamless and welded.