Super Duplex Pipe Fittings
Giriraj Impex is a manufacturer, stockist, supplier and exporter of super duplex pipe fittings in UNS S32750 (2507) and UNS S32760. We manufacture super duplex butt-weld fittings to ASTM A815 in grades WPS32750 and WPS32760 to ASME B16.9, and forged socket weld and threaded fittings and olets in ASTM A182 F53 and F55 to ASME B16.11 and MSS SP-97.
Super duplex pipe fittings are used wherever super duplex pipe is installed – offshore seawater, firewater and produced-water systems, water injection, desalination high-pressure piping and high-chloride process lines – so that every elbow, tee and branch has the same PREN of 40 or more as the pipe.
Specifications
| Item | Butt-weld fittings | Forged fittings |
|---|---|---|
| Material | ASTM A815 / ASME SA815 WPS32750, WPS32760 | ASTM A182 F53, F55 |
| Dimensions | ASME B16.9; MSS SP-43 | ASME B16.11; MSS SP-97 |
| Sizes | ½" to 48" NB | ⅛" to 4" NB |
| Wall / class | Sch 10S, 40S, 80S and heavier, to match the pipe | Class 3000, 6000, 9000 |
| Construction | Seamless (S) or welded (W, WX) | Forged and machined |
| Condition | Solution annealed and rapidly cooled; pickled and passivated | |
| Optional tests | Ferrite count, impact test, ASTM A923, ASTM G48, radiography, liquid penetrant | |
| Documents | Mill test certificate (MTC) with PREN; third-party inspection on request | |
Grades and composition
ASTM A815 designates super duplex butt-weld fittings WPS32750 and WPS32760, followed by a class letter for seamless or welded construction. Forged fittings use the A182 grades F53 (S32750) and F55 (S32760). The UNS composition limits are the same for pipe, plate, fittings and forgings:
| 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.
For less severe chloride duties, duplex 2205 fittings are often sufficient.
Fitting types
- Elbows – 45°, 90° and 180°, long and short radius.
- Tees – equal and reducing.
- Reducers – concentric and eccentric.
- Caps and stub ends.
- Forged fittings – socket weld and threaded elbows, tees, couplings, plugs.
- Olets – weldolets, sockolets and threadolets for branches and instrument connections.
Why fittings need the same care as pipe
Fittings are formed by bending, bulging and pressing, often at elevated temperature, and then heat treated. In super duplex, this processing is where problems can arise: insufficient solution annealing or slow cooling of thick sections can leave brittle intermetallic phases, while overheating can upset the ferrite–austenite balance. Either lowers toughness and pitting resistance precisely at bends and branches, where stresses and turbulence are highest. For this reason, projects usually apply the same supplementary tests to fittings as to pipe – ferrite count, Charpy impact tests at low temperature, ASTM A923 and ASTM G48 – and we produce and test fittings to the project specification sent with the order.
Manufacturing, marking and inspection
Seamless fittings are formed from super duplex pipe, and larger welded fittings from plate, then solution annealed, quenched, pickled and machined to ASME B16.25 bevels. Welded fittings have their welds radiographed as the class requires. Each fitting is dimensionally inspected and marked with the manufacturer's identification, grade and class, size, schedule and heat number. The mill test certificate reports composition, PREN, mechanical properties and supplementary test results. Third-party inspection is available on request, and fittings can be supplied to NACE MR0175 / ISO 15156 on request.
Welding and installation
Super duplex fittings are welded to super duplex pipe with procedures qualified for the project, controlling heat input and interpass temperature and using over-alloyed filler metal and suitable shielding and backing gas. Welds are normally checked for ferrite and may be corrosion tested during procedure qualification. Installed systems should be flushed and drained correctly after hydrotesting, because stagnant untreated water left in lines can cause corrosion even in super duplex.
Ordering
Please state the fitting type, standard, size and reducing size, schedule, grade and class (for example WPS32750-S), quantity, the project material specification and the inspection required.
Applications and related products
Super duplex pipe fittings are used in offshore seawater lift, firewater, cooling water and produced-water systems, water injection and subsea manifolds, desalination high-pressure lines and chemical plants handling chloride-rich streams. They join super duplex pipes and tubes to super duplex flanges, bolted with super duplex fasteners. We also supply super duplex plates and super duplex round bars. See all fitting materials on the pipe fittings page and grade guidance on the duplex and super duplex steel page.
Frequently Asked Questions
ASTM A815 (ASME SA815) covers wrought super duplex piping fittings in grades WPS32750 and WPS32760, with dimensions to ASME B16.9.
Forged socket weld and threaded super duplex fittings and olets are made from ASTM A182 F53 (UNS S32750) or F55 (UNS S32760), with dimensions to ASME B16.11 and MSS SP-97.
Forming and heat treatment can create brittle phases or disturb the phase balance. Ferrite measurement, impact tests, ASTM A923 and G48 tests confirm the fittings have the toughness and corrosion resistance of the pipe.
Both are super duplex grades with similar properties, but project specifications normally name one UNS number. Fittings should be ordered in the grade the specification requires.
Many specifications allow welded fittings in larger sizes, with the welds fully radiographed (class WX) and the fitting solution annealed. Smaller sizes are usually seamless.
Yes. Weldolets, sockolets and threadolets are supplied in A182 F53 and F55 to MSS SP-97, matched to the run and branch pipe sizes and schedules.
Request a Quote for Super Duplex Pipe Fittings
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