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 Tube, UNS S32750 ASTM A789
Super Duplex 2507 tube in UNS S32750 (EN 1.4410, X2CrNiMoN25-7-4) is the standard heat-exchanger and instrumentation tube grade for chloride-bearing service in seawater coolers, FGD economisers, desalination evaporators, oil and gas separators and the chemical-industry condensers where 6 percent molybdenum austenitics pit. TorqBolt holds 2507 tube at the Mumbai warehouse in NPS 1/4" through 8" and OD 6 mm to 219.1 mm, both seamless and welded, with EN 10204 Type 3.1 mill certificates and Type 3.2 third-party-witnessed on request.
The tube is supplied to ASTM A789 for seamless and welded ferritic / austenitic stainless steel tube for general service and EN 10216-5 (seamless pressure tube) or EN 10217-7 (welded pressure tube) for European supply. Sour-service certification per NACE MR0175 / ISO 15156-3 is available with controlled hardness, ferrite content and pitting performance.
Super Duplex 2507 Tube Size Range
| Form | Size Range | Schedule / Wall |
|---|---|---|
| Seamless tube (ASTM A789) | OD 6 mm to 168 mm (NPS 1/4" to 6") | SCH 5S, 10S, 40S, 80S, 160 |
| Welded tube (ASTM A789) | OD 50 mm to 219 mm (NPS 2" to 8") | SCH 10S, 40S, 80S |
| U-bent heat-exchanger tube | Straight length 6 to 24 m, U-bend per TEMA | BWG 14, 16, 18 typical |
| Instrumentation tube (cold-drawn) | OD 1/4" to 1" | 0.035, 0.049, 0.065 wall typical |
| Length | Random 5.8 to 7.0 m, double random 11 to 13 m, cut-to-length | |
Super Duplex 2507 Tube Chemistry per ASTM A789
Per ASTM A789 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 | A789 Min % | A789 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 |
| Manganese | (no min) | 1.20 |
| Silicon | (no min) | 0.80 |
Super Duplex 2507 Tube Mechanical Properties
| Property | Minimum | Test Standard |
|---|---|---|
| Tensile strength | 795 MPa (115 ksi) | ASTM A370 |
| Yield strength (0.2 percent offset) | 550 MPa (80 ksi) | ASTM A370 |
| Elongation in 50 mm | 15 percent (longitudinal) | ASTM A370 |
| Hardness | 32 HRC max, 28 HRC max NACE | NACE MR0175 |
| Charpy V-notch at minus 46 C | 45 J min | NORSOK M-630 |
| Hydrostatic test | To pressure per A1016 paragraph 19 | ASTM A1016 |
| Eddy-current test | Per A789 supplementary requirement | ASTM A789, A1016 |
Seamless vs Welded Tube
- Seamless (extruded or hot-pierced): preferred for OD 6 mm to 168 mm. No weld seam, no longitudinal HAZ. Required by some end-users for critical sour service and high-pressure heat exchangers.
- Welded (longitudinal seam, EW or HFW): cost-effective for OD 50 mm to 219 mm. Weld seam is solution-annealed in line, ferrite content controlled per NORSOK M-630, eddy-current tested per A789.
- U-bent heat-exchanger tube: straight tube cold-bent to TEMA U-bend radii, then solution annealed and water quenched to recover ferrite balance and remove cold work residual stress.
Super Duplex 2507 Tube Applications
- Heat-exchanger U-tubes for seawater coolers, FGD economisers, MED and MSF desalination units
- Instrumentation tubing for offshore platforms and process plants in chloride exposure
- Hydraulic and umbilical tube on subsea production systems
- Condenser and evaporator tube for chemical and pulp and paper bleach plants
- Oil and gas separator coils, glycol contactor coils and reboilers
Related Products and Standards
- Super Duplex 2507 pipe per A790
- Super Duplex 2507 welded pipe
- Super Duplex 2507 fittings per A815 WP-S32750
- Super Duplex 2507 flanges per A182 F53
- Super Duplex 2507 welding wire ER2594 / ER2553
- ASTM A789 standard reference
Super Duplex 2507 Tube FAQ
Which standards cover 2507 tube?
ASTM A789 (seamless and welded ferritic / austenitic tube, designation S32750), EN 10216-5 (European pressure-purpose seamless), EN 10217-7 (European pressure-purpose welded), NORSOK M-630 (material data sheet), NACE MR0175 / ISO 15156-3 for sour service. Heat-exchanger U-tubes follow TEMA RCB-2.31 for bend radius and post-bend heat treatment.
What is the size range for 2507 tube?
Seamless: OD 6 mm to 168 mm (NPS 1/4" to 6"). Welded: OD 50 mm to 219 mm (NPS 2" to 8"). Schedules 5S through 160. U-bend tube straight length 6 to 24 m, BWG 14, 16, 18 typical for heat exchangers.
Do U-bent tubes need post-bend heat treatment?
Yes. Cold bending generates residual stress and can lower ferrite balance in the bend region. Per TEMA RCB-2.31 and NORSOK M-630, U-bent super duplex tubes are solution annealed at 1040 to 1100 degrees Celsius and water quenched after bending to restore microstructure and corrosion performance.
Is 2507 tube suitable for sour service?
Yes, qualified per NACE MR0175 / ISO 15156-3 with hardness restricted to 28 HRC maximum and ferrite content within 35 to 65 percent. The application zone, H2S partial pressure and chloride limits are stated on the EN 10204 Type 3.1 or 3.2 certificate when ordered with NACE compliance.
What welding filler do I use for field welds on 2507 tube?
ER2594 (overmatching, slightly higher PREN) or ER2553 (matching) per AWS A5.9. Heat input 0.5 to 2.5 kJ per millimetre, interpass below 150 degrees Celsius, argon plus 2 to 5 percent nitrogen shielding for GTAW root pass. Tube-to-tubesheet welds are normally autogenous orbital GTAW on thin walls.
Does 2507 tube contain copper?
No, copper is not an intentional alloying element in UNS S32750. ASTM A789 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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