Duplex Steel Pipe Fittings
Giriraj Impex is a manufacturer, stockist, supplier and exporter of duplex pipe fittings in duplex 2205. We manufacture duplex butt-weld fittings to ASTM A815 in grades WPS31803 and WPS32205 to ASME B16.9 and MSS SP-43, and forged socket weld and threaded fittings and olets to ASTM A182 F51 and F60 to ASME B16.11 and MSS SP-97.
Duplex pipe fittings carry the strength and chloride resistance of duplex 2205 through every bend, branch and size change in a duplex piping system – offshore, desalination, seawater cooling, chemical and pulp and paper service.
Specifications
| Item | Butt-weld fittings | Forged fittings |
|---|---|---|
| Material | ASTM A815 / ASME SA815 WPS31803, WPS32205 | ASTM A182 F51, F60 |
| 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 5S, 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 | |
| Documents | Mill test certificate (MTC) with PREN; third-party inspection on request | |
ASTM A815 grades and classes
ASTM A815 covers wrought ferritic, ferritic/austenitic and martensitic stainless steel piping fittings. Duplex 2205 fittings are designated WPS31803 or WPS32205 – "WP" for wrought pipe fitting, "S" for stainless, followed by the UNS number. A class suffix shows the construction: S for seamless, W for welded with radiography of the fitting maker's welds, and WX where all welds including those in the starting material are radiographed. Fittings are commonly dual certified to both UNS numbers. The composition limits are the same as for duplex pipe:
| 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.
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 and plugs.
- Olets – weldolets, sockolets, threadolets.
Forming and heat treatment
Duplex fittings are formed from duplex pipe or plate and then solution annealed and rapidly cooled. This step is essential: forming at temperature, or slow cooling afterwards, can create brittle intermetallic phases or upset the ferrite–austenite balance, lowering toughness and corrosion resistance. For the same reason, project specifications often call for ferrite measurement, Charpy impact tests, ASTM A923 testing and ASTM G48 pitting tests on fittings as well as on pipe. Ends are machined to ASME B16.25 bevels to match the pipe wall.
Marking, inspection and ordering
Each fitting is dimensionally inspected and marked with the manufacturer's identification, grade and class, size, schedule and heat number. The mill test certificate shows composition, PREN, mechanical properties and the results of any supplementary tests. Third-party inspection is available on request, and fittings can be supplied to NACE MR0175 / ISO 15156 on request.
Please state the fitting type, standard, size and reducing size, schedule, grade (WPS31803, WPS32205 or dual) and class, quantity, and any supplementary tests or inspection required.
Welding duplex fittings
Fittings are welded to duplex pipe with the same qualified procedure used for the pipe: controlled heat input and interpass temperature, over-alloyed filler metal and suitable shielding and backing gas. Weld root oxidation should be removed and the joint pickled and passivated. Because fittings concentrate stresses in bends and branches, consistent material quality across pipe, fittings and flanges is important to the life of a duplex system.
Ordering notes for projects
On oil and gas and desalination projects, duplex fittings are normally ordered against a project material specification that adds requirements to ASTM A815 – for example a maximum ferrite range, impact test temperature and energy, ASTM A923 method, G48 test temperature and maximum hardness. Please send the specification with the enquiry so that every fitting in the order is produced and tested to it. Pipe, fittings and flanges ordered against the same specification give a consistent duplex system.
Applications and related products
Duplex pipe fittings are used in offshore process, produced-water and seawater lines, desalination plants, chemical and fertiliser plants, pulp and paper bleaching and heat-exchanger connections. They join duplex pipes and tubes to duplex flanges, bolted with duplex fasteners. We also supply duplex plates and 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 duplex and other ferritic and martensitic stainless steel piping fittings. Duplex 2205 fittings are designated WPS31803 or WPS32205, with dimensions to ASME B16.9.
WPS32205 is the A815 grade for duplex 2205 (UNS S32205) wrought fittings, and S is the class showing seamless construction. W and WX classes indicate welded fittings with different radiography requirements.
Forged socket weld and threaded duplex fittings are made from ASTM A182 F51 or F60 material, with dimensions to ASME B16.11.
Forming can disturb the balance of ferrite and austenite and create brittle phases. Solution annealing followed by rapid cooling restores the correct structure, toughness and corrosion resistance.
Yes. Duplex fittings can be supplied in thin-wall schedules such as 5S and 10S to MSS SP-43 for low-pressure lines.
Yes. Pipes, fittings, flanges and fasteners in duplex 2205 can be supplied together with consistent testing and certification.
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