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Duplex Flanges are forged flanges built under ASTM A182 / ASME SA182, dimensioned to ASME B16.5 and B16.47, offering roughly double the yield strength of 316L stainless flanges plus far stronger chloride pitting resistance for offshore, desalination and chemical process piping.
1/2″ - 48″ NB
Forged, faced and drilled to spec
ASTM / ASME A182 & SA182
Dimensions per ASME B16.5 & B16.47
UNS S31803 / S32205
Duplex 2205 - WNR 1.4462 equivalent
150 to 2500
Rated up to 400°F service
35 Minimum
Outperforms 316L flanges in chlorides
EN 10204 3.1 / 3.2
NACE MR0175 & PMI on request
Stocked, Not Scheduled
Weld neck, blind and slip-on sit ready to ship - nothing waits on a forge slot
Chemistry Proven, Not Promised
Every parent heat scanned and logged before it ever touches a saw
Odd Class? No Problem
Off-catalogue ratings and bores forged straight off your drawing
Today's Rate, Locked Today
Confirm your order and the nickel index stops moving against you
Container-Ready On Day One
MTC, COO and seaworthy crating leave with the same shipment
One Engineer Owns Your Order
The person who quotes you signs off on your dispatch too
📌 Table of Contents
Sourcing a duplex flange for a live shutdown window isn't like sourcing carbon steel. Get one PREN number wrong, or skip a PMI scan, and the whole tie-in slips by weeks. As a working Duplex Flanges Manufacturer in India, we build against exactly that risk: chemistry checked heat by heat, the common classes sitting in yard stock, and one person who owns your enquiry from RFQ all the way to the bill of lading.
Every Duplex 2205 Flange we ship carries the chemistry buyers actually ask for UNS S31803 or S32205, WNR 1.4462, ASME SA182 grade F51/F60 , forged and faced in-house, not routed through some trading desk. Got an odd class or an unusual bore size? We'll forge and machine it to your drawing instead of just saying we're out of stock.
Whether it's headed to a refinery in Cairo, a desalination plant in Casablanca, or a terminal in Houston, it ships export-ready MTC and Certificate of Origin already attached, so there's nothing to chase once the container's sailed.
As a hands-on Duplex Flanges Manufacturer In India, we forge to the exact spec you send, not the nearest catalogue size.
No forge wait – every common type is already forged, machined and MTC-ready in our Mumbai yard.
All 15 forms above are held ex-stock in Duplex Stainless S31803 and Duplex 2205 S32205 at our Mumbai forge yard. Every form above ships from a single Duplex Flanges Supplier In India desk, so nothing gets lost between quote and dispatch.
Send us the P&ID call-out - we'll confirm the right type and face in minutes.
Every class from 150 to 2500 is held ex-stock, matched to your mating pipe schedule.
| Temperature (°F) | Working Pressure | |||||||
|---|---|---|---|---|---|---|---|---|
| 300 | 75 | 600 | 1500 | 900 | 400 | 150 | 2500 | |
| 300°F | 665 | 115 | 1335 | 3335 | 2000 | 890 | 230 | 5560 |
| 200°F | 745 | 130 | 1490 | 3720 | 2230 | 990 | 260 | 6200 |
| -20~100°F | 750 | 145 | 1500 | 3750 | 2250 | 1000 | 290 | 6250 |
| 500°F | 580 | 85 | 1160 | 2905 | 1740 | 775 | 170 | 4840 |
| 400°F | 615 | 100 | 1230 | 3070 | 1845 | 820 | 200 | 5120 |
| 650°F | 545 | 60 | 1095 | 2735 | 1640 | 730 | 125 | 4560 |
| 600°F | 555 | 70 | 1115 | 2785 | 1670 | 740 | 140 | 4640 |
| 750°F | 530 | - | 1065 | 2660 | 1595 | 710 | 95 | 4430 |
| 700°F | 540 | - | 1085 | 2710 | 1625 | 725 | 110 | 4520 |
Figures per ASME B16.5 Group 2.8 duplex material chart; confirm exact rating against your line design temperature. Working as a Duplex Flanges Stockist In Mumbai lets us confirm class and rating against live yard stock in minutes.
Open-die forged shapes, not resold semi-finished blanks
Alloy content checked on the shop floor before machining
Bolt circles held to ASME B16.5 tolerance, every batch
MTC, COO and packing list issued same desk, no delay
Beyond India, we operate as a genuine Duplex Flanges Exporter, shipping MTC-backed cargo to five continents.
Grade & class confirmed
PMI on source heat
Face, bore, drill
MTC 3.1 / 3.2
Export-ready crating
Being a true Duplex Flanges Manufacturer In India means forging happens in-house, not through a third party.
Ask any fabricator in Western India and they'll point to us as their go-to Duplex Flanges Stockist In Mumbai.
Preferred root pass method for tight ferrite-austenite balance control
Faster fill and cap passes on thicker wall duplex joints
Used for field repairs and access-restricted joint positions
Interpass temperature is held below 150°C on every method to protect the duplex phase balance. As your Duplex Flanges Supplier In India, we can recommend the weld procedure before your fitter even opens the drawing.
Governed by ASTM A182 / ASME SA182
Governed by EN 10222-5 / EN 10204
Governed by JIS G3214
Governed by BS 4504 / EN 1092-1
As a Duplex Flanges Exporter, we map every standard equivalent so your import paperwork clears without a query.
Where Our Duplex Flanges Reach Across The Middle East
Share the standard and class you're quoting against - we'll return a firm number same day.
| Element | S31803 (%) | S32205 (%) |
|---|---|---|
| Chromium (Cr) | 21.0 - 23.0 | 22.0 - 23.0 |
| Nickel (Ni) | 4.5 - 6.5 | 4.5 - 6.5 |
| Molybdenum (Mo) | 2.5 - 3.5 | 3.0 - 3.5 |
| Nitrogen (N) | 0.08 - 0.20 | 0.14 - 0.20 |
| Carbon (C) max | 0.03 | 0.03 |
Being the Duplex Flanges Manufacturer In India that runs its own PMI lab means chemistry never leaves the yard unverified.
Values per ASTM A182 / ASME SA182 annex tables for forged duplex fittings.
Our position as a Duplex Flanges Stockist In Mumbai means these strength figures are backed by physical stock, not a catalogue promise.
Fast quenching after annealing is what keeps the ferrite-austenite ratio near 50/50. Every Duplex Flanges Supplier In India claims fast delivery - we back it with annealing records on file for every heat.
Wall thickness is checked against your drawing before the flange ever leaves our floor.
OD 152 mm · Bolt Circle 120 mm · 4 Bolts × M14
OD 228 mm · Bolt Circle 190 mm · 8 Bolts × M18
OD 330 mm · Bolt Circle 270 mm · 12 Bolts × M22
OD 343 mm · Bolt Circle 298 mm · 8 Bolts × M22
OD 406 mm · Bolt Circle 356 mm · 16 Bolts × M25
OD 508 mm · Bolt Circle 432 mm · 20 Bolts × M30
| NPS | OD | RF Dia. (R) |
Min. Thickness (T) |
Diameter of Holes | No. of Bolt Holes | Bolt Circle (BC) |
WN Bore ID (WB) |
SO Bore ID (SB) |
Dia. of Hub Top (HT) |
Dia. Hub Base (HB) |
WN LTH (WL) |
SO LTH (SL) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1⁄2 | 3.50 | 1.38 | 0.38 | 0.62 | 4 | 2.38 | 0.62 | 0.88 | 0.84 | 1.19 | 1.81 | 0.56 |
| 11⁄2 | 5.00 | 2.88 | 0.62 | 0.62 | 4 | 3.88 | 1.61 | 1.95 | 1.90 | 2.56 | 2.38 | 0.81 |
| 2 | 6.00 | 3.62 | 0.69 | 0.75 | 4 | 4.75 | 2.07 | 2.44 | 2.38 | 3.06 | 2.44 | 0.94 |
| 3⁄4 | 3.88 | 1.69 | 0.44 | 0.62 | 4 | 2.75 | 0.82 | 1.09 | 1.05 | 1.50 | 2.00 | 0.56 |
| 1 | 4.25 | 2.00 | 0.50 | 0.62 | 4 | 3.12 | 1.05 | 1.36 | 1.32 | 1.94 | 2.12 | 0.62 |
| 21⁄2 | 7.00 | 4.12 | 0.81 | 0.75 | 4 | 5.50 | 2.47 | 2.94 | 2.88 | 3.56 | 2.69 | 1.06 |
| 3 | 7.50 | 5.00 | 0.88 | 0.75 | 4 | 6.00 | 3.07 | 3.57 | 3.50 | 4.25 | 2.69 | 1.12 |
| 4 | 9.00 | 6.19 | 0.88 | 0.75 | 8 | 7.50 | 4.03 | 4.57 | 4.50 | 5.31 | 2.94 | 1.25 |
| 31⁄2 | 8.50 | 5.50 | 0.88 | 0.75 | 8 | 7.00 | 3.55 | 4.07 | 4.00 | 4.81 | 2.75 | 1.19 |
| 5 | 10.00 | 7.31 | 0.88 | 0.88 | 8 | 8.50 | 5.05 | 5.66 | 5.56 | 6.44 | 3.44 | 1.38 |
| 6 | 11.00 | 8.50 | 0.94 | 0.88 | 8 | 9.50 | 6.07 | 6.72 | 6.63 | 7.56 | 3.44 | 1.50 |
| 10 | 16.00 | 12.75 | 1.12 | 1.00 | 12 | 14.25 | 10.02 | 10.88 | 10.75 | 12.00 | 3.94 | 1.88 |
| 8 | 13.50 | 10.62 | 1.06 | 0.88 | 8 | 11.75 | 7.98 | 8.72 | 8.63 | 9.69 | 3.94 | 1.69 |
| 14 | 21.00 | 16.25 | 1.31 | 1.12 | 12 | 18.75 | 13.25 | 14.14 | 14.00 | 15.75 | 4.94 | 2.19 |
| 12 | 19.00 | 15.00 | 1.19 | 1.00 | 12 | 17.00 | 12.00 | 12.88 | 12.75 | 14.38 | 4.44 | 2.12 |
| 18 | 25.00 | 21.00 | 1.50 | 1.25 | 16 | 22.75 | 17.25 | 18.18 | 18.00 | 19.88 | 5.44 | 2.62 |
| 11⁄4 | 4.62 | 2.50 | 0.56 | 0.62 | 4 | 3.50 | 1.38 | 1.70 | 1.66 | 2.31 | 2.19 | 0.75 |
| 16 | 23.50 | 18.50 | 1.38 | 1.12 | 16 | 21.25 | 15.25 | 16.16 | 16.00 | 18.00 | 4.94 | 2.44 |
| 22 | 29.50 | 25.25 | 1.75 | 1.38 | 20 | 27.25 | 21.25 | 22.22 | 22.00 | 24.25 | 5.82 | 3.07 |
| 20 | 27.50 | 23.00 | 1.62 | 1.25 | 20 | 25.00 | 19.25 | 20.20 | 20.00 | 22.00 | 5.62 | 2.81 |
| 24 | 32.00 | 27.25 | 1.81 | 1.38 | 20 | 29.50 | 23.25 | 24.25 | 24.00 | 26.12 | 5.94 | 3.19 |
Full dimensional tables for every class and NB are issued instantly against your enquiry.
| NPS | Weld Neck flange | Blind flange | Socket Weld flange | Slip On flange |
|---|---|---|---|---|
| 1/2 | 1.98 | 1.98 | 1.98 | 1.10 |
| 1 | 3.08 | 1.98 | 1.98 | 1.98 |
| 1¼ | 3.08 | 3.08 | 3.08 | 3.08 |
| 6 | 25.79 | 26.89 | 18.95 | 18.95 |
| 2 | 5.95 | 11.17 | 5.07 | 5.07 |
| 8 | 41.66 | 46.73 | 29.76 | 29.76 |
| 16 | 138.89 | 178.5 | 97.22 | 105.16 |
| 3 | 11.46 | 19.90 | 9.03 | 9.03 |
| 3½ | 11.90 | 13.00 | 8.81 | 8.81 |
| 1½ | 3.96 | 3.96 | 3.08 | 3.08 |
| 22 | 223.32 | 352.29 | 183.64 | 183.64 |
| 24 | 265.87 | 426.59 | 218.25 | 218.25 |
| 2½ | 9.92 | 7.05 | 7.93 | 7.93 |
| 5 | 20.94 | 19.84 | 14.99 | 14.99 |
| 4 | 16.31 | 16.97 | 13.00 | 13.00 |
| 10 | 53.57 | 69.44 | 42.76 | 42.76 |
| 12 | 87.30 | 122.13 | 63.49 | 63.49 |
| 18 | 163.80 | 218.25 | 128.97 | 128.97 |
| 14 | 113.09 | 138.8 | 89.28 | 89.28 |
| 3/4 | 1.98 | 1.98 | 1.98 | 1.98 |
| 20 | 195.55 | 282.8 | 163.80 | 163.80 |
Weights vary slightly by facing and forging tolerance - exact mass confirmed on the mill test certificate.
As a Duplex Flanges Exporter with weekly sailings, we can quote landed cost, not just an ex-works number.
Correct HSN code on every invoice, packed and papered for a smooth export clearance.
Molybdenum, nickel and nitrogen content lift resistance well past standard 316L
A stable, self-healing passive oxide film forms across the flange face
The balanced ferrite-austenite structure blocks pitting from taking hold
Ferrite content adds strong resistance to chloride stress corrosion cracking
Offshore Oil & Gas
Seawater Desalination
Chemical Processing
Marine & Shipbuilding
Pulp & Paper Mills
Pharmaceutical Plants
Power & Fertiliser Plants
Flue Gas Desulphurisation
Standard mill certificate
Third-party witnessed
Alloy scan on every heat
Sour-service compliance
Marine class approval
Offshore certification
Independent verification
Quality management system
Tell us the class, NB and quantity - we'll flag what's in yard stock for immediate dispatch.
Class 300 WNRF, UNS S32205, PMI tested, EN 10204 3.1 MTC.
Offshore EPC Contractor, Egypt
Cairo, EgyptClass 150 Blind, UNS S31803, hydro tested, NACE MR0175.
Desalination Plant Operator, Saudi Arabia
Dammam, Saudi ArabiaClass 600 RTJ, UNS S32205, PMI checked on every heat.
Chemical Plant Contractor, South Africa
Johannesburg, South AfricaClass 300 WNRF, UNS S31803, third-party witnessed hydro test.
Marine Terminal EPC, USA
Houston, USAClass 150 Slip-On, UNS S32205, PMI verified, EN 10204 3.1 MTC.
Pulp & Paper Contractor, Morocco
Casablanca, MoroccoClass 900 WNRF, UNS S31803, hydro tested, MTC 3.1/3.2.
Fertiliser Plant EPC, Mexico
Mexico City, Mexico
UNS S31803 and S32205 (Duplex 2205) are the standard flange grades, equivalent to WNR 1.4462 and covered under ASTM A182 / ASME SA182.
Flange face and bolting dimensions follow ASME B16.5 up to 24 inch NB, and ASME B16.47 Series A or B for larger diameters.
Class 150, 300, 600, 900, 1500 and 2500 are all forged in duplex 2205, sized to match the mating pipe schedule and service pressure.
Mildly, yes. The mixed ferritic-austenitic grain structure gives duplex flanges a slight magnetic response, unlike fully austenitic 316L flanges.
An EN 10204 3.1 mill certificate ships as standard. 3.2 third-party certification, NACE MR0175 compliance and PMI reports are available on request.
Duplex Flanges are classified under HSN 7307, attracting 18% GST across most forged flange sub-categories in India.
Common classes and NB sizes held in yard stock dispatch within 24 to 48 hours; off-list forged sizes typically take 5 to 7 weeks.
Share your class, NB and face type - get a locked quote back within 2 hours.
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