Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175 / ISO 15156-2
- NORSOK M-650 Qualified
- API 6A Certified
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Super Duplex 2507 Welded Pipe, UNS S32750 ASTM A790
Super Duplex 2507 welded pipe in UNS S32750 (EN 1.4410) is the cost-effective piping form for sizes NPS 6" through 24" where seamless production is mill-limited and welded construction with in-line solution anneal delivers equivalent corrosion performance. TorqBolt holds 2507 welded pipe in HFW (high-frequency welded) and EFW (electric fusion welded) routes at the Mumbai warehouse, with the longitudinal seam re-annealed and the body solution annealed and water quenched, supplied with EN 10204 Type 3.1 certificates and Type 3.2 third-party-witnessed on request.
The pipe is supplied to ASTM A790 for seamless and welded ferritic / austenitic stainless steel pipe and EN 10217-7 for European pressure-purpose welded supply. Companion fittings to ASTM A815 WP-S32750; flanges to ASTM A182 F53. Sour-service per NACE MR0175 / ISO 15156-3 available.
Super Duplex 2507 Welded Pipe Size Range
| Form | Size Range | Schedule |
|---|---|---|
| HFW (high-frequency welded) | NPS 6" to 16" (DN 150 to DN 400) | SCH 10S, 40S, 80S |
| EFW (electric fusion welded) | NPS 16" to 24" and above (DN 400+) | Custom thickness, X-ray inspected |
| Length | Random 5.8 to 7.0 m, double random 11 to 13 m, cut-to-length on request | |
| End preparation | Plain, bevelled per ASME B16.25, threaded per ASME B1.20.1 | |
Super Duplex 2507 Welded Pipe Chemistry per ASTM A790
Per ASTM A790 designation S32750: 25Cr-7Ni-3.5Mo-0.3N. Copper is restricted to 0.50 max as residual, not intentional. PREN of 41 or higher.
| Element | Min % | Max % |
|---|---|---|
| Carbon | (no min) | 0.030 |
| Chromium | 24.0 | 26.0 |
| Nickel | 6.0 | 8.0 |
| Molybdenum | 3.0 | 5.0 |
| Nitrogen | 0.24 | 0.32 |
| Copper | (no min) | 0.50 max, residual, not intentional |
Super Duplex 2507 Welded Pipe Mechanical Properties
| Property | Minimum | Test Standard |
|---|---|---|
| Tensile strength | 795 MPa (115 ksi) | ASTM A370 |
| Yield strength | 550 MPa (80 ksi) | ASTM A370 |
| Elongation in 50 mm | 15 percent | ASTM A370 |
| Hardness (sour-service) | 28 HRC max | NACE MR0175 |
| Charpy V-notch at minus 46 C | 45 J min full set | NORSOK M-630, ASTM E23 |
| Weld ferrite content | 35 to 65 percent | ASTM E562 |
| Hydrostatic test | To pressure per A999 paragraph 8 | ASTM A999 |
| Radiography | Per A790 supplementary on EFW pipe | ASTM A790, ASME V |
HFW vs EFW Welded Pipe
- HFW (high-frequency welded): longitudinal seam welded by induction or resistance heating, no filler metal. Used for NPS 6" to 16". Seam is forge-welded then re-annealed in line. Eddy-current and ultrasonic seam inspection per ASTM A790.
- EFW (electric fusion welded): longitudinal seam welded with super duplex filler ER2594 / ER2553 per AWS A5.9. Used for NPS 16" and above where HFW is impractical. X-ray inspected per ASTM A790 and ASME Section V.
- Body heat treatment: full pipe solution annealed at 1040 to 1100 degrees Celsius and water quenched after welding so the seam ferrite content matches the body envelope (35 to 65 percent in weld, 35 to 55 percent in base).
Field Welding Welded Pipe
- Filler ER2594 (overmatching) or ER2553 (matching) per AWS A5.9
- Heat input 0.5 to 2.5 kJ per millimetre, interpass temperature below 150 degrees Celsius
- Argon plus 2 to 5 percent nitrogen shielding for GTAW root pass
- WPS qualified per ASME IX with NORSOK M-601 acceptance criteria
- Post-weld ferrite count target 35 to 65 percent in weld metal per ASTM E562
Super Duplex 2507 Welded Pipe Applications
- Seawater service piping for offshore platforms, ship sea-chest and ballast water
- FGD wet flue-gas-desulfurization absorber and scrubber piping
- Desalination MSF and MED brine recirculation and high-pressure feed lines
- Oil and gas process piping for production and separation duty
- Pulp and paper bleach plant chlorine dioxide and chlorine piping
Related Products and Standards
- Super Duplex 2507 pipe overview (seamless plus welded)
- Super Duplex 2507 tube per A789
- Super Duplex 2507 fittings per A815 WP-S32750
- Super Duplex 2507 flanges per A182 F53
- Super Duplex 2507 welding wire ER2594 / ER2553
- ASTM A790 standard reference
Super Duplex 2507 Welded Pipe FAQ
Is welded 2507 pipe inferior to seamless?
No, when properly produced. ASTM A790 covers both forms with the same chemistry, mechanical properties and corrosion test requirements. The longitudinal seam is re-annealed in line so the weld ferrite balance matches the base metal. NORSOK M-630 acceptance applies equally to seamless and welded.
When do I specify EFW instead of HFW?
EFW is normal above NPS 16" where HFW becomes impractical due to forming and heating limits. EFW uses super duplex filler (ER2594 / ER2553) and full radiographic inspection per A790. HFW below NPS 16" is filler-free and uses ultrasonic and eddy-current seam inspection.
What is the size range for welded 2507 pipe?
HFW: NPS 6" to 16" (DN 150 to DN 400). EFW: NPS 16" and above (DN 400 plus). Schedules 10S, 40S, 80S standard, with custom wall thickness on EFW. Length random 5.8 to 7.0 m, double random 11 to 13 m, cut-to-length on request.
Is welded 2507 pipe acceptable for NACE sour service?
Yes, with weld ferrite controlled to 35 to 65 percent and hardness held below 28 HRC. The certificate states the application zone, H2S partial pressure and chloride limits when ordered with NACE MR0175 / ISO 15156-3 compliance. Many North Sea operators routinely accept welded 2507 in sour service.
Does 2507 welded pipe contain copper?
No, copper is not an intentional alloying element in UNS S32750. ASTM A790 permits 0.50 max as residual, not intentional. Copper-bearing super duplex grades are Zeron 100 (S32760) and Ferralium 255 (S32550), which are different alloys.
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