ASTM A789
Seamless and welded duplex stainless steel tubing
Covers seamless and welded duplex and super duplex stainless steel tubing for general corrosive service, with an emphasis on stress-corrosion-cracking resistance.
- Pipe & tube
- ASME SA-789
- 3 grades supplied to it
Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026
What is ASTM A789?
ASTM A789 is the specification for seamless and welded duplex (ferritic/austenitic) stainless steel tubing for general service, including heat-exchanger tubes. It covers duplex 2205 (S31803, S32205) and super duplex S32750 and S32760. Pipe in the same grades is ordered to ASTM A790. ASME adopts it as SA-789.
ASTM A789 at a glance
| Products | Tubing — ordered by outside diameter and wall |
|---|---|
| Grades | S31803, S32205, S32750, S32760 and others |
| General requirements | ASTM A1016 |
| ASME designation | SA-789 |
A789 tubing vs A790 pipe
| ASTM A789 | ASTM A790 | |
|---|---|---|
| Product | Tubing | Pipe |
| Sized by | OD and wall (mm or in) | NPS and schedule |
| General requirements | A1016 | A999 |
| Typical use | Heat exchangers, instrumentation, hydraulic lines | Process piping |
How to write ASTM A789 on a purchase order
Name the product, size, material specification and grade, the dimensional standard and the certificate. An example line:
Illustrative only — sizes, tests, inspection level and any project values come from your purchase specification.
ASTM A789 edition and verification status
Which edition we have confirmed, and what is still being checked before any numerical requirement is published here.
| Current edition (publisher listing) | A789/A789M-24 — checked 7 October 2026 |
|---|---|
| Full-text verification | In progress — numerical requirements are published here only after the current text has been reviewed |
| Edition on your order | The edition named in your purchase order or design code governs — confirm it with your enquiry |
What to know before ordering to ASTM A789
The points that decide whether material to ASTM A789 is accepted at inspection.
- Tubing is ordered by OD and wall thickness, not by NPS and schedule.
- Heat-exchanger and instrumentation tubing in 2205 and 2507 is typically bought to A789.
- Pipe in the same grades is ASTM A790.
Grades and products we supply to ASTM A789
| Grade | Product | Designation on the certificate |
|---|---|---|
| Duplex 2205 | Pipe & Tube | ASTM A789 |
| Super Duplex 2507 | Pipe & Tube | ASTM A789 |
| Super Duplex S32760 | Pipe & Tube | ASTM A789 |
How ASTM A789 fits into an order
A purchase order line is only complete when it names the material standard, the dimensional standard and the inspection document. Miss one and the mill, the inspector and the buyer can each read the order differently.
Standards used with ASTM A789
Same family
ASTM A789 — questions buyers ask
What is ASTM A789?
ASTM A789 is the specification for seamless and welded duplex (ferritic/austenitic) stainless steel tubing for general service, including heat-exchanger tubes. It covers duplex 2205 (S31803, S32205) and super duplex S32750 and S32760. Pipe in the same grades is ordered to ASTM A790. ASME adopts it as SA-789.
What is the difference between A789 and A790?
A789 covers tubing (sized by OD and wall); A790 covers pipe (sized by NPS and schedule).
Is A789 used for heat-exchanger tubes?
Yes — duplex heat-exchanger and condenser tubes are commonly ordered to A789.
Which grades do you supply to ASTM A789?
Duplex 2205, Super Duplex 2507, Super Duplex S32760 — see the table on this page for the exact product and designation.
What is the current edition of ASTM A789?
The publisher's listing checked on 7 October 2026 shows A789/A789M-24 as the current edition. The edition that governs an order is the one named in the purchase order or design code. Full-text review of the current edition is in progress, so numerical requirements are not published on this page yet.
Do you supply certificates to this standard?
Yes. Material is supplied with mill test certificates to EN 10204 3.1 showing the standard, grade and heat number; 3.2 with third-party inspection on request.
Sources: the ASTM / ASME specifications named on this page and producer datasheets · Last updated October 2026