ASTM A789 Duplex Stainless Steel Heat Exchanger Tubes
Product Name:Duplex Stainless Steel Heat Exchanger Tubes
Standard:ASTM A789 / ASME SA789
Product Type:Seamless / Welded Tubes
Material Grades:UNS S31803 / S32205 UNS S32750 , UNS S32760
Tube Type:Heat Exchanger Tube / Boiler Tube / Condenser Tube
Manufacturing Process:Cold Drawn / Cold Rolled / Seamless / Welded
Outer Diameter (OD):6.00–630 mm
Wall Thickness:0.5–30 mm
Length:3000–12000 mm; Custom Length Available
Heat Treatment:Solution Annealing + Rapid Cooling
Surface Finish:Pickled & Passivated / Bright Annealed / Polished
Testing:Hydrostatic Test / Pneumatic Test / Eddy Current Test / Ultrasonic Test
Certification:EN 10204 3.1 / 3.2 MTC Available
Send E-mail:info@gneestainless.com
Tel:+8615824687445
Description
Gnee Steel (Tianjin) Co., Ltd. is one of the most professional manufacturers and suppliers of ASTM A789 Duplex Stainless Steel Heat Exchanger Tubes in China. With abundant experience, we warmly welcome you to wholesale customized ASTM A789 Duplex Stainless Steel Heat Exchanger Tubes from our factory. For price consultation, contact us.
If you are seeking heat exchanger tubing that combines high strength and long service life for use in high-chloride environments, high-pressure conditions, and highly corrosive media, ASTM A789 duplex stainless steel tubing offers a lightweight, cost-effective alternative that outperforms traditional 316L and 317L grades. It is specifically engineered for applications-such as oil refining, petrochemical processing, seawater desalination, marine engineering, and marine condensers-that demand superior resistance to stress corrosion cracking (SCC) and high pressure-bearing capabilities.
What is the ASTM A789 standard?
ASTM A789/A789M standard covers seamless and welded ferritic-austenitic (duplex) stainless steel tubing, focusing on resistance to general corrosion and stress corrosion cracking. Compared to conventional austenitic stainless steels, duplex grades such as UNS S32205 (Duplex 2205) offer a minimum tensile strength of 655 MPa, a yield strength of 485 MPa, and an elongation of 25%; meanwhile, super duplex grade UNS S32750 achieves a minimum tensile strength of 800 MPa and a yield strength of 550 MPa. This high strength-to-weight ratio allows engineers to consider thinner wall thicknesses in appropriate designs.
Delivery Condition: The ASTM A789 standard mandates that tubing be supplied in a specific heat-treated condition and requires mechanical property testing alongside non-destructive electrical testing or hydrostatic testing, thereby ensuring critical quality assurance for heat exchanger applications.
ASTM A789 Duplex Stainless Steel Tube Suppliers and Manufacturers
GNEE supplies ASTM A789 duplex stainless steel heat exchanger tubing in various common grades (including UNS S31803, S32205, S32750, and S32760). Available in both seamless and welded forms, these tubes undergo cold drawing/cold rolling, solution annealing, and rapid water quenching in accordance with grade-specific requirements. For instance, S32205 is typically solution annealed at 1020–1100°C, whereas S32750 requires processing at approximately 1025–1125°C. GNEE offers customization regarding outside diameter, wall thickness, length, surface finish, and U-bend specifications, complemented by dimensional inspection, mechanical testing, hydrostatic or eddy current testing (depending on specific requirements), and EN 10204 3.1/3.2 material certification.
ASTM A789 UNS S31803 Duplex Stainless Steel Tube
ASTM A789 Tube Specification
| Types | Out diameter | Length | Wall thickness |
|---|---|---|---|
| NB Sizes (available) | 1/8" ~ 8" | Upto 6 Meters | SCH 40 /SCH 10 /SCH 160/ SCH 5 / SCH 80 |
| ASTM A789 Seamless Tubing (as per need) | 5.00 milimeter ~ 203.02 milimeter | as per need | |
| ASTM A789 Welded Tubing (available + as per need) | 5.00 milimeter ~ 1219.02 milimeter | 1.00 ~ 15.00 milimeter |
Heat Treatment (Solution Annealing)
All tubes must be furnished in the heat-treated condition.
| Grade | Annealing Temperature (Min.) | Quenching Method |
| S32205 / S31803 | 1900°F (1040°C) | Rapid cooling in water or air |
| S32750 | 1880°F – 2060°F (1025°C – 1125°C) | Rapid water quench |
| S32304 | 1700°F – 1920°F (925°C – 1050°C) | Rapid cooling |
ASTM A789 Duplex Heat Exchanger Tubes Chemical Composition
Duplex steel is characterized by its high Chromium, Molybdenum, and Nitrogen content.
| Grade (UNS) | Common Name | Cr (%) | Ni (%) | Mo (%) | N (%) | Others |
| S32205 | Duplex 2205 | 22.0 – 23.0 | 4.5 – 6.5 | 3.0 – 3.5 | 0.14 – 0.20 | - |
| S31803 | Standard Duplex | 21.0 – 23.0 | 4.5 – 6.5 | 2.5 – 3.5 | 0.08 – 0.20 | - |
| S32750 | Super Duplex 2507 | 24.0 – 26.0 | 6.0 – 8.0 | 3.0 – 5.0 | 0.24 – 0.32 | Cu: 0.5 max |
| S32304 | Lean Duplex 2304 | 21.5 – 24.5 | 3.0 – 5.5 | 0.05 – 0.6 | 0.05 – 0.20 | Cu: 0.05-0.6 |
ASTM A789 Duplex Stainless Steel Tubes Mechanical Properties
Duplex grades provide nearly double the yield strength of standard austenitic stainless steels (304/316).
| Property | S32205 / S31803 | S32750 (Super Duplex) | S32304 |
| Tensile Strength, min. | 95 ksi (655 MPa) | 116 ksi (800 MPa) | 87 ksi (600 MPa) |
| Yield Strength (0.2%), min. | 65 ksi (450 MPa) | 80 ksi (550 MPa) | 58 ksi (400 MPa) |
| Elongation (in 2in.), min. | 25% | 15% | 25% |
| Hardness (Rockwell C), max. | 31 HRC | 32 HRC | 32 HRC |
| Hardness (Brinell), max. | 293 HBW | 310 HBW | 290 HBW |
Pressure Rating Chart ASTM A789 Duplex Steel Tube
| ASTM A789 Tubing O.D. (in.) |
Wall Thickness of ASTM A789 Tubing (inches) | |||||||
|---|---|---|---|---|---|---|---|---|
| 0.028 | 0.035 | 0.083 | 0.049 | 0.065 | 0.095 | 0.109 | 0.120 | |
| Working Pressure (psig) | ||||||||
| 1/8 | 7900 | 10100 | ||||||
| 1/4 | 3700 | 4800 | 7000 | 9500 | ||||
| 5/16 | 3700 | 5400 | 7300 | |||||
| 3/8 | 3100 | 4400 | 6100 | |||||
| 1/2 | 2300 | 3200 | 4400 | |||||
| 3/4 | 4000 | 2200 | 3000 | 4600 | ||||
| 1 | 2900 | 2200 | 3400 | 3900 | 4300 | |||
SA 789 Duplex Boiler Tubes Permissible Variations in Dimensions
| O.D. (d) mm | PVavw % | PVod mm | PVL mm | PVmiw % |
|---|---|---|---|---|
| d＜12.7 | ±15 | ±0.13 | (3, 0) | (30, 0) |
| 12.7≤d＜38.1 | ±10 | ±0.13 | (3, 0) | (20, 0) |
| 38.1≤d＜88.9 | ±10 | ±0.25 | (5, 0) | (20, 0) |
| 88.9≤d＜139.7 | ±10 | ±0.38 | (5, 0) | (20, 0) |
| 139.7≤d＜203.2 | ±10 | ±0.76 | (5, 0) | (20, 0) |
ASTM A789 Duplex Stainless Steel Tubes applications:
Seawater desalination and marine cooling circuits;
Offshore oil and gas platforms and subsea systems;
Chemical and petrochemical processing plants;
Pulp and paper industries, and general fluid transport in environments involving highly corrosive chlorides.
ASTM A789 UNS S32750 vs. S32205: How to Choose?
S32205 is suitable for conventional chemical processing, oil and gas pipelines, and environments involving moderate seawater exposure;
S32750 is suitable for deep-sea marine systems, high-temperature/high-concentration chloride solutions, and harsh marine or desulfurization environments.
Temperature limits: To avoid detrimental "sigma-phase" embrittlement, the maximum operating temperature for both materials is approximately 315°C (600°F); however, super duplex stainless steel requires stricter monitoring under high-temperature operating conditions.
If you are willing, please let me know:
the specific grade you require (e.g., S32205 or S32750),
whether you need seamless or welded pipe, and the expected operating temperature and pressure.
I can assist you in finding the precise technical data or dimensional specifications suitable for your project.
Lead time
| Supply Type | Estimated Lead Time | Remarks |
|---|---|---|
| Stock | 3–10 Days | Limited to standard sizes such as 19.05 mm and 25.4 mm OD. Re-inspection and repackaging are required before shipment. |
| Standard Production | 30–50 Days | Production starts from steel billets, followed by piercing, cold drawing, solution annealing, and complete mechanical and quality testing. |
| Custom / Large Order | 60–90 Days | Applicable to special dimensions, special testing such as ASTM G48 corrosion testing, or Super Duplex grades such as UNS S32750. |
| U-Bent Tubes | +7–15 Days | Additional time required after straight tube production for U-bending, stress relief treatment, and leak-tightness testing. |
ASTM A789M Super Duplex Steel Tube testing
Intergranular corrosion test: In accordance with ASTM A262 or ASTM G48 (for pitting corrosion).
Mechanical testing: Includes tensile, yield, elongation, hardness, flattening, and flaring tests.
Non-destructive testing (NDT): Each tube must undergo eddy current testing (ET) or ultrasonic testing (UT).
Hydrostatic test: To ensure leak-tightness under pressure.
Standard export packaging
Pipe End Protection: Plastic caps are fitted to both ends of each pipe to prevent the ingress of dust, moisture, and debris.
Woven Bags/Plastic Film: Bundles are wrapped in waterproof woven bags or plastic sheeting to protect against salt spray corrosion during sea transport.
Wooden Cases for Sea Transport: Reinforced wooden cases with internal dividers are recommended for thin-walled or high-precision heat exchanger tubes to prevent them from colliding with one another.
Fumigation: All wooden packaging for export complies with IPPC international fumigation standards.
FAQ
What is the difference between ASTM A789 and ASTM A790?
ASTM A789: This standard applies to tubing. It is typically used in heat exchangers and is custom-made according to outer diameter (OD) and wall thickness (WT), with higher requirements for dimensional accuracy (such as roundness and wall thickness tolerances).
ASTM A790: This standard applies to nominal pipes. It is typically used for fluid transport piping and is manufactured according to nominal diameter (NPS/Schedule).
What are S32205 and S31803? Are they interchangeable?
S31803: This is the earliest standard for 2205 duplex stainless steel.
S32205: This is an improved version of S31803, offering higher corrosion resistance by raising the lower limits for chromium, molybdenum, and nitrogen.
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