Super Duplex S32750 and S32760 Pipes and Tubes for Seawater and Aggressive Chloride Service
UNS S32750 (2507) and UNS S32760 are two separate super duplex stainless steel grades with about 25% chromium, 7% nickel, 3 to 5% molybdenum and 0.20 to 0.32% nitrogen; S32760 also contains copper and tungsten. Pipe is ordered to ASTM A790 / ASME SA790 by NPS and schedule, and tubing to ASTM A789 / ASME SA789 by OD and wall thickness.
Dinesh Tube India supplies S32750 and S32760 seamless pipes and tubes from Mumbai, with welded pipe on request and EN 10204 3.1 mill test certificates. State the grade exactly as your specification names it.
What Is Super Duplex Stainless Steel?
Super duplex steels have a balanced austenite-ferrite structure like duplex 2205, but with higher chromium, molybdenum and nitrogen. That gives a pitting resistance equivalent (PREN) of 40 or more, resistance to chloride stress corrosion cracking and crevice corrosion in seawater, and a minimum yield strength of 550 MPa, more than twice that of 316L. Like other duplex grades they are magnetic and are generally limited to service below about 250 to 300 °C.
S32750 or S32760: Which Super Duplex Grade?
The two grades are not interchangeable: a specification that names S32760 requires its copper and tungsten additions, and S32750 has a different strength and elongation basis. Order the UNS number on your specification; if your project accepts either grade, say so in the enquiry.
Pipe or Tube: ASTM A790 or A789?
Seamless or Welded: Which Do You Need?
Sizes: NPS and Schedule for Pipe, OD and Wall for Tube
Pipe is commonly supplied from 1/2" to 12" NPS in SCH 10S to SCH 80S, and tube from 6.35 to 50.8 mm OD; other sizes on request. Ends: plain or bevelled for pipe, plain for tube.
Delivery Condition
Which Tests and Documents Can You Specify?
Chemical Composition of S32750 and S32760 (%)
Per ASTM A790 / A789; iron is the balance. S32760 also requires %Cr + 3.3 × %Mo + 16 × %N ≥ 40.
Mechanical and Physical Properties of S32750 and S32760
Values for A790 pipe; A789 tube minimums and hardness limits can differ slightly. Check the edition named in your order.
Super Duplex Equivalent Grades
Equivalents are the nearest national grades, not identical specifications; confirm the required standard before ordering. SAF 2507 is a trademark of Alleima.
Super Duplex S32750 / S32760 Pipe & Tube Specification
Pipe
Tube
Grades
Pipe Sizes
Tube Sizes
Delivery Condition
Ends
Certification
Types of Super Duplex Pipes & Tubes
Super Duplex Seamless Pipes
Super Duplex Welded Pipes
Super Duplex Seamless Tubes
Super Duplex Welded Tubes
How to Order Super Duplex Pipe: RFQ Example
A complete enquiry lets us quote in one round. Replace the values with your own; for tube, give OD × wall instead of NPS and schedule.
Send your super duplex RFQ in this format to kamlesh@dineshtube-india.com, call or WhatsApp +91 83559 10913, or send an enquiry.
Where Are S32750 and S32760 Pipes and Tubes Used?
Need a different grade? See super duplex S32950, duplex S32205, duplex S31803 or the full super duplex pipes and tubes range.
Super Duplex S32750 / S32760: FAQs
What is the difference between S32750 and S32760?
Both are 25Cr-7Ni super duplex stainless steels with PREN of 40 or more. S32760 has deliberate additions of copper (0.50 to 1.00%) and tungsten (0.50 to 1.00%) and slightly lower molybdenum (3.0 to 4.0%), while S32750 has up to 5.0% Mo and higher nitrogen. In ASTM A790 pipe, S32750 has a higher tensile minimum (800 MPa against 750 MPa) and S32760 a higher elongation minimum (25% against 15%). They are separate grades: order the UNS number on your specification.
Is 2507 the same as S32750?
2507 is the common name for UNS S32750 (25% Cr, 7% Ni, about 4% Mo), originally developed as SAF 2507. Its European equivalent is 1.4410 and its forging grade is ASTM A182 F53. S32760 is a different grade (1.4501, F55).
What is the difference between super duplex and duplex 2205?
Super duplex has about 25% chromium, more molybdenum and nitrogen, and PREN of 40 or more, against about 22% chromium and PREN of about 34 to 35 for 2205 (S32205). Minimum yield strength is 550 MPa against 485 MPa. Super duplex is chosen for seawater and other aggressive chloride service where 2205 is not enough. See our duplex S32205 page.
What is the PREN of S32750 and S32760?
PREN = %Cr + 3.3 × %Mo + 16 × %N (for S32760 often written %Cr + 3.3 × (%Mo + 0.5 × %W) + 16 × %N). Typical super duplex material is 41 to 43. ASTM A790 requires PREN of at least 40 for S32760; for S32750, specify PREN 40 minimum in your order if your project requires it, because the lowest composition limits give a lower value.
What is the maximum temperature for super duplex pipe?
Super duplex steels are generally not used for long-term service above about 250 to 300 °C, because the ferrite phase can embrittle. The allowable limit for pressure parts is set by your design code, such as ASME B31.3.
Which tests are specific to super duplex pipe and tube?
Besides the tests required by A790 or A789, buyers commonly specify ASTM A923 (harmful intermetallic phases), ferrite content (often 35 to 55%), ASTM G48 pitting corrosion test, Charpy impact test at low temperature, and PMI. Specify the methods and acceptance criteria in your order.
What should a super duplex enquiry include?
Give the grade (S32750 or S32760), the product and specification (A790 pipe or A789 tube), seamless or welded, size (NPS and schedule for pipe, OD and wall for tube), length, ends, quantity, tests (A923, ferrite, G48, impact, PMI), documents (EN 10204 3.1, 3.2 or third-party inspection) and the delivery date.
Export Destinations for Super Duplex Pipes & Tubes
We supply S32750 and S32760 pipes and tubes within India and export to EPC contractors, fabricators and plants in the Middle East, Africa, Asia, Europe and the Americas. Tell us your destination port when you enquire.