Super Duplex Flanges
Giriraj Impex is a manufacturer, stockist, supplier and exporter of super duplex flanges to ASTM A182 grade F53 (UNS S32750, 2507) and F55 (UNS S32760). We manufacture super duplex flanges to ASME B16.5 from ½" to 24" NB in Class 150 to 2500, ASME B16.47 Series A and B, EN 1092-1 and to customer drawings, in weld neck, slip-on, blind, socket weld, lap joint and orifice types with raised face or ring type joint facings.
Super duplex flanges complete seawater, firewater, produced-water and high-chloride process systems offshore and onshore, where the flange, gasket face and bolting must all resist pitting and crevice corrosion for the life of the plant.
Specifications
| Item | Details |
|---|---|
| Material standard | ASTM A182 / ASME SA182 |
| Grades | F53 (UNS S32750), F55 (UNS S32760) |
| Dimensional standards | ASME B16.5, B16.47 Series A and B, B16.36, B16.48, EN 1092-1, MSS SP-44 |
| Sizes | ½" to 24" NB (B16.5); 26" to 60" NB (B16.47) |
| Classes | 150, 300, 600, 900, 1500, 2500 |
| Facings | Raised face, ring type joint, flat face |
| Condition | Solution annealed and rapidly cooled |
| Optional tests | Ferrite count, impact test, ASTM A923, ASTM G48, ultrasonic test |
| Documents | Mill test certificate (MTC) with PREN; third-party inspection on request |
F53 and F55
F53 is the A182 forging grade for super duplex 2507 (S32750) and F55 for S32760, which adds copper and tungsten and is known by the trade name Zeron 100. Both have a PREN of 40 or more. Projects usually name one grade, and the UNS number should be stated on the order. The composition limits are the same as for super duplex pipe and plate:
| UNS | Grade | C | Mn | P | S | Si | Cr | Ni | Mo | N | Other elements |
|---|---|---|---|---|---|---|---|---|---|---|---|
| S31803 | 2205 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | – |
| S32205 | 2205 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | – |
| S32750 | 2507 | 0.030 | 1.20 | 0.035 | 0.020 | 0.80 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 | Cu 0.50 |
| S32760 | Zeron 100 type | 0.030 | 1.00 | 0.030 | 0.010 | 1.00 | 24.0–26.0 | 6.0–8.0 | 3.0–4.0 | 0.20–0.30 | Cu 0.50–1.00, W 0.50–1.00 |
S32760 also requires a minimum PREN of 40. Footnotes as given in the standards.
Flange types
- Weld neck flanges – the standard choice for super duplex process and seawater lines.
- Blind flanges – for line ends and nozzles.
- Slip-on flanges – where the specification allows.
- Lap joint flanges with super duplex stub ends, socket weld, orifice and reducing flanges.
- Spectacle blinds and spades.
- Compact flanges and special flanges to drawings.
Manufacturing and testing
Super duplex flanges are forged, solution annealed and quenched, then machined. Large and heavy forgings need especially careful heat treatment, because thick sections cool more slowly and are more prone to intermetallic phases. Oil and gas specifications therefore commonly call for ferrite measurement, Charpy impact tests at low temperature, ASTM A923 testing and ASTM G48 pitting tests, sometimes on test pieces taken from a sacrificial forging of the same heat and section. Each flange is dimensionally inspected and marked with the manufacturer's identification, grade, size, class, bore schedule and heat number. Flanges can be supplied to NACE MR0175 / ISO 15156 on request.
Bolting, gaskets and isolation
Super duplex flanges are normally bolted with super duplex studs and nuts so that the bolting has the same seawater resistance as the flange. Gasket materials are chosen to avoid crevice corrosion at the flange face. Where super duplex lines connect to carbon steel or other alloys, insulating gasket kits prevent galvanic corrosion. See duplex and super duplex fasteners.
Ordering
Please state the flange type, standard, size, class, facing, bore schedule, grade (F53 or F55), quantity, minimum PREN and the supplementary tests and inspection required.
Pressure ratings and design
ASME B16.5 includes super duplex forgings in its material groups, with pressure-temperature ratings by class. Because of their high strength, super duplex flanges carry high ratings at ambient and moderate temperatures, but they are limited to the temperature range set in the standard and the design code. For weight-critical offshore piping, compact flange designs in super duplex are sometimes specified; their rating comes from the design standard used for the compact flange rather than from B16.5.
Applications and related products
Super duplex flanges are used offshore for seawater lift, firewater, cooling and produced-water systems, in water injection and subsea equipment, in desalination plants, seawater-cooled power and process plants, and chemical plants handling chloride-rich streams. They connect super duplex pipes and tubes and super duplex pipe fittings. Flanges and blinds can also be produced from super duplex plates and super duplex round bars where the specification allows. See all flange materials on the flanges page and grade guidance on the duplex and super duplex steel page.
Frequently Asked Questions
F53 is the ASTM A182 grade for forged super duplex stainless steel UNS S32750 (2507). F53 flanges are used with super duplex pipe and fittings in seawater and high-chloride service.
F53 is UNS S32750 and F55 is UNS S32760, which adds copper and tungsten and has a specified minimum PREN of 40. Both are super duplex grades; projects normally specify one of them.
Slow cooling of thick forgings can form brittle intermetallic phases that reduce toughness and corrosion resistance. Correct solution annealing and quenching, verified by tests such as ASTM A923, prevents this.
Super duplex studs and nuts are normally used so the bolting matches the flange's seawater resistance. Coated alloy bolting is sometimes allowed by the project specification.
Yes. Ring type joint facings are supplied for high-pressure classes, along with raised face and flat face flanges.
Yes. Super duplex flanges can be supplied to NACE MR0175 / ISO 15156 on request, with the required hardness and testing.
Request a Quote for Super Duplex Flanges
Tell us the product, grade, size, standard, quantity and delivery location, and our sales team will reply with a quotation.
Zeron® 100 is a trademark of Rolled Alloys.