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 Hollow Bar, UNS S32750
Super Duplex 2507 hollow bar in UNS S32750 (EN 1.4410) is centrifugal-cast or trepanned hollow stock that saves 60 to 80 percent of the machining time when finished parts have a bore of 25 mm or larger. Sleeves, couplings, valve seats, bushings and short pipe runs all benefit from starting on a pre-bored bar instead of drilling solid round. TorqBolt holds 2507 hollow bar from OD 25 to 350 mm with bores 12 to 250 mm at the Mumbai warehouse, with EN 10204 Type 3.1 certificates and Type 3.2 third-party-witnessed on request.
Hollow bar follows ASTM A479 chemistry and ASTM A511 dimensional rules for mechanical hollow stainless tube. Centrifugal-cast hollow stock follows ASTM A890 grade 5A or A995 grade 5A. Sour-service certification per NACE MR0175 / ISO 15156-3 is available.
Super Duplex 2507 Hollow Bar Size Range
| Outside Diameter | Bore | Wall |
|---|---|---|
| 25 mm to 50 mm | 12 mm to 30 mm | 5 mm to 12 mm |
| 50 mm to 100 mm | 25 mm to 70 mm | 10 mm to 30 mm |
| 100 mm to 200 mm | 50 mm to 150 mm | 20 mm to 50 mm |
| 200 mm to 350 mm | 100 mm to 250 mm | 30 mm to 80 mm |
| Length | 3.0 to 6.0 m random, cut-to-length on request | |
Super Duplex 2507 Hollow Bar Chemistry
Per ASTM A479 designation S32750 (wrought) or A890 grade 5A (cast): 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 Hollow Bar Mechanical Properties
| Property | Minimum | Test Standard |
|---|---|---|
| Tensile strength | 795 MPa (115 ksi) wrought, 690 MPa (100 ksi) cast | ASTM A370 |
| Yield strength | 550 MPa wrought, 485 MPa cast | ASTM A370 |
| Elongation in 50 mm | 15 percent wrought, 18 percent cast | ASTM A370 |
| Hardness | 32 HRC max, 28 HRC max NACE | NACE MR0175 |
| Charpy V-notch at minus 46 C | 45 J min wrought, 40 J min cast | NORSOK M-630 |
Centrifugal-Cast vs Trepanned Hollow Bar
- Centrifugal-cast (ASTM A890 grade 5A): molten 2507 cast into a rotating die produces a near-net hollow with dense, fine-grained structure. Used for OD above 100 mm where solid forging is uneconomic.
- Trepanned: solid round bar is gun-drilled or trepanned to produce the bore. Used for short runs and small bores below 50 mm where casting is not justified.
- Welded hollow: from rolled and welded ASTM A789 / A790 tube. Used for thinner walls and longer lengths.
Super Duplex 2507 Hollow Bar Applications
- Sleeves, couplings and adapter bushings for chloride pump and valve service
- Valve seats, retainers and seal carriers in sour-service trim
- Short pipe runs, instrument fittings and bored couplings
- Hydraulic cylinder liners and seal sleeves on subsea actuators
- Heat-exchanger end-cap forging stock with pre-bored cores
Related Products and Standards
- Super Duplex 2507 round bar
- Super Duplex 2507 tube
- Super Duplex 2507 pipe
- Super Duplex 2507 fittings
- ASTM A479 reference
Super Duplex 2507 Hollow Bar FAQ
When does hollow bar beat solid round?
When the finished part has a bore of 25 mm or larger. Drilling 2507 from solid wastes tool life and consumes machining hours; starting on pre-bored hollow saves 60 to 80 percent of cycle time. The crossover depends on bore-to-OD ratio and lot quantity.
What standards cover 2507 hollow bar?
ASTM A511 (mechanical hollow stainless tube), ASTM A789 (seamless duplex tube, used as hollow stock), ASTM A479 (chemistry), ASTM A890 grade 5A and ASTM A995 grade 5A (centrifugal-cast super duplex), EN 10088-3 Werkstoff 1.4410, NORSOK M-630 and NACE MR0175.
Is centrifugal-cast 2507 the same as wrought?
Chemistry is the same band, but cast properties are slightly lower (UTS 690 MPa min, YS 485 MPa min) versus wrought (UTS 795, YS 550). Cast 2507 is qualified separately as ASTM A890 grade 5A or A995 grade 5A. Both meet PREN 40 minimum and NORSOK M-630 ferrite requirements when properly heat-treated.
Can hollow bar be NACE-certified?
Yes, both wrought and centrifugal-cast hollow can be supplied to NACE MR0175 / ISO 15156-3 with 28 HRC max hardness and ferrite within the 35 to 65 percent band. The application zone is stated on the certificate.
Does 2507 hollow bar contain copper?
No, copper is not an intentional alloying element in UNS S32750. ASTM A479 permits 0.50 max as residual, not intentional. Copper-bearing super duplex grades (Zeron 100 S32760, Ferralium 255 S32550) are different alloys.
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