Amigo Impex is a Mumbai-based duplex steel pipe fittings manufacturer, stockist, supplier and exporter in the alloy piping trade since 2013. Butt-weld elbows, tees, reducers, end caps and stub ends are certified to ASTM A815/ASME SA-815 in classes WP-S, WP-W, WP-WX and WP-WU, with ASME B16.9 covering dimensions, while forged socket-weld and threaded pieces follow ASTM A182 grade F51 under ASME B16.11. One grade anchors the range: Duplex S31803. Ferrite and austenite split the microstructure almost evenly, pairing high strength with chloride resistance.
SA-815 sets the S31803 floor at 90 ksi (620 MPa) tensile and 65 ksi (450 MPa) yield. Chromium held at 21.0 to 23.0%, with 2.5 to 3.5% molybdenum and 0.08 to 0.20% nitrogen, resists pitting and stress corrosion cracking in chloride-bearing and brine circuits; for critical seawater duty, super duplex is the safer choice. Sizes span 1/2 inch to 12 inches NB across SCH 10S to XXS. Chemical plants, oil and gas processing, marine piping and water treatment lines take the bulk of dispatches. Cutting, machining, threading, fabrication, testing and packing all run inside our own works, and roughly 60 to 70 tonnes of material stands ready in Mumbai, and we hold AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018 certifications. A mill test certificate accompanies every order, and a priced offer follows your enquiry within the working day.
Grade, size band, schedule, end preparation and paperwork decide whether a fitting suits a line class, so the table below records the parameters our duplex steel pipe fittings are supplied against.
A duplex fitting answers two layers of documents. Material specifications fix chemistry, heat treatment and test duty for ASTM A815 duplex fittings, while dimensional standards control geometry, wall and tolerance.
| Standard | Scope |
|---|---|
| ASTM A815 / ASME SA-815 | Wrought ferritic/austenitic stainless steel piping fittings |
| ASTM A182 / ASME SA-182 | Duplex forgings for socket weld and threaded fittings, F51 |
| ASME B16.9 | Factory-made wrought buttwelding fittings |
| ASME B16.11 | Forged fittings, socket welding and threaded |
| MSS SP-43 | Wrought and fabricated butt-welding fittings for low pressure, corrosion resistant applications; basis of ASTM A815 class CR |
| EN 10253-4 | European butt-welding fittings, austenitic-ferritic grades |
| ASTM A790 | Companion duplex pipe the fittings are welded into |
| NACE MR0175 / ISO 15156 | Sour service material qualification, on request |
One duplex steel pipe fitting grade covers our orders, and pitting resistance is ranked by the PREN figure, which counts chromium, molybdenum and nitrogen together.
S31803 duplex pipe fittings combine high strength with chloride resistance for demanding industrial piping applications. European drawings identify this alloy by Werkstoff number 1.4462, and Japanese enquiries may use SUS 329J3L.
Bore and wall thickness settle availability faster than anything else. Butt-weld stock covers the ASME B16.9 band tabled here, and where a standard bore isn't enough, duplex pipe fittings are produced against drawings.
| Fitting Group | Governing Standard | Size Range | Wall or Class |
|---|---|---|---|
| Buttweld elbows, tees, reducers, caps, crosses and stub ends | ASME B16.9 | 1/2 inch to 12 inch NB | SCH 10S, 40S, 80S, 160 and XXS |
| Long-radius and short-radius elbows | ASME B16.9 | 1/2 inch to 12 inch NB | Matched to the connecting pipe |
| Long-radius elbows and returns | ASME B16.9 | 1/2 inch to 12 inch NB | Matched to the connecting pipe |
| Short-radius elbows and returns | ASME B16.9 | 1 inch to 12 inch NB | Matched to the connecting pipe |
| Forged socket weld and threaded fittings | ASME B16.11 | Quoted per enquiry | Pressure class to order |
| Bores above 12 inch NB | ASME B16.9 | Up to 48 inch NB, made to order | To pipe schedule |
| Non-standard geometry or dimensions | ASME B16.9 para. 4.4.2, marked with suffix S58 (ASTM A960) | Made to order |
12 stocked configurations turn, branch, reduce and terminate a duplex line. Each duplex steel butt-weld fitting in the list ships marked with grade and heat number, bevelled, ready for the root run.
Contact us at Amigo Impex for the best price on Duplex Steel Pipe Fittings.
Request a QuotePacking follows the piece, not a single carton size. Bevelled buttweld items travel in timber crates with edge protection, small forged fittings go boxed, and mixed lots carry strapped bundles with tags recording grade, size, schedule and heat number. Dispatch from Mumbai serves pan-India, while export consignments of duplex steel pipe fittings move to the USA, the Gulf, Europe and Asia. Ready material moves out in 1 to 2 days, and produced-to-order lots need about 30 days.
Weld class drives the test scope on UNS S31803 fittings: class WP-W covers fittings whose fabrication welds have been radiographed, class WP-WX covers fittings whose welds have all been radiographed, and class WP-WU covers fittings whose welds have all been ultrasonically tested. A923 screening for detrimental intermetallic phase runs whenever the order names it. Positive material identification and a dimensional check against B16.9 or B16.11 close out each batch before packing. The mill test certificate pairs original mill data with results from our own testing; third-party inspection agencies attend release checks on request, and we hold AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018 certifications.
60–70 tonnes held in Mumbai, with urgent requirements dispatched within one to two days.
AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018, with an MTC on every order.
Cutting, machining, threading, fabrication and testing all handled at our own Mumbai facility.
Original mill certificates plus our own test reports, so every batch can be traced back.
Non-standard sizes and specifications made to order.
Dispatched from Mumbai to every major Indian city, and exported to USA, Gulf, Europe, Asia
ASTM A815, issued by ASME as SA-815, covers duplex steel pipe fittings of seamless and welded buttweld construction. Forged socket weld and threaded fittings are certified to ASTM A182 grade F51 under ASME B16.11 dimensions.
Stocked duplex steel pipe fittings run 1/2 inch to 12 inch NB in SCH 10S, 40S, 80S, 160 and XXS to ASME B16.9 dimensions. Larger bores follow as made-to-order production.
Duplex pipe fittings replace 316L once chlorides begin pitting or cracking the austenitic grade. The 65 ksi (450 MPa) yield floor also beats the 25 ksi (170 MPa) set for WP316L fittings, permitting thinner walls at equal pressure.
Welds on duplex steel pipe fittings of S31803 base metal use matching filler or nominal 22Cr-9Ni-3Mo weld metal, the E2209/ER2209 class. Fittings ship solution annealed, ready for the fabrication weld.
A mill test certificate travels with every duplex steel pipe fittings order, combining the original mill document with our own test results. Third-party inspection agencies witness the release when the purchase order requires it.
We hold roughly 60 to 70 tonnes of alloy stock in Mumbai, and ready duplex fittings are dispatched in 1 to 2 days. Made-to-order items, including non-standard bores, need about 30 days.
Chloride resistance at a workable price point sends S31803 duplex fittings into these eight industries.
