Duplex Steel Pipe Fittings Manufactured and Exported in Mumbai
If you are searching for duplex steel pipe fittings that hold up in chloride-heavy service, you are probably past the stage of asking what duplex is. You want to know who can supply it properly. Kalpataru Piping Solution manufactures duplex pipe fittings to ASTM A815 UNS S31803 and S32205, with super duplex S32750 available on request, at our Mumbai facility. Every elbow, tee, reducer, cap and stub end follows ASME B16.9, comes in sizes from 1/2″ to 24″ NB, and is checked for PMI, ferrite balance and hydrostatic integrity before it leaves the shop floor. Each shipment carries an EN 10204 3.1 mill certificate with traceable heat numbers, which is the paperwork inspectors and EPC teams ask for first. Whether your line carries seawater, produced water, brine or an aggressive process stream, duplex gives you more than twice the yield strength of 316L, so thinner walls and lighter spools often become possible without giving up safety margin. Send us your size list and grade, and we will reply with firm pricing within 24 hours.
Table of content
- What Are Duplex Steel Pipe Fittings?
- Duplex Steel Pipe Fittings Grades
- What Is ASTM A815 and Why Does It Matter?
- Duplex Steel Pipe Fittings Grades: UNS S31803, S32205 and S32750s
- Technical Data
- Types of Duplex Steel Pipe Fittings
- Duplex Steel Pipe Fittings Price List
- People Ask About Duplex Steel Pipe Fittings Manufacturer
What Are Duplex Steel Pipe Fittings?
Duplex steel pipe fittings are the elbows, tees, reducers, caps, crosses, stub ends and bends that let a piping system change direction, change size or branch off, made from stainless steel with a two-phase structure. Roughly half of that structure is austenite and half is ferrite. It is not simply a stronger version of 316L. It is a different family of steel, and each phase does a different job.
- Ferrite brings high strength and strong resistance to chloride stress corrosion cracking.
- Austenite brings toughness, formability and the weldability that makes field fabrication realistic.
- Nitrogen, chromium and molybdenum lift pitting and crevice corrosion resistance well beyond the 300-series grades.
The result is a fitting that can handle seawater, brine and sour process fluids at a wall thickness that would be unsafe in 316L. That is why duplex stainless steel pipe fittings have become the default for offshore platforms, desalination plants and chemical processing lines.
What Is ASTM A815 and Why Does It Matter?
ASTM A815 (ASME SA815 for pressure-vessel and boiler applications) is the governing specification for wrought ferritic, ferritic/austenitic and martensitic stainless steel piping fittings. For duplex buyers, it is the document that defines the chemistry, heat treatment, mechanical tests and marking you should expect on every fitting. When a purchase order simply says “duplex elbow”, the supplier has room to interpret it. When it says ASTM A815 UNS S31803 or UNS S32205, the interpretation is fixed.
The standard also divides fittings into classes, and this is where many enquiries go wrong:
A815 Class | Construction | Radiography | Typical use |
|---|---|---|---|
WP-S | Seamless | Not required | General process lines, most seamless fittings |
WP-W | Welded (fitting made from welded pipe or plate) | Weld not radiographed | Lower-severity service, larger sizes |
WP-WX | Welded | All welds 100% radiographed | Higher-integrity service, joint efficiency 1.0 |
Alongside it, ASME B16.9 sets the dimensions of butt-weld fittings, ASME B16.28 covers short-radius elbows and returns, ASME B16.11 covers forged socket-weld and threaded fittings, and MSS SP-43 covers light-wall stub ends. We supply against all of these.
Duplex Steel Pipe Fittings Grades: UNS S31803, S32205 and S32750
Grade | UNS / ASTM A815 reference | Common names | Matching forged grade | Approx. PREN |
|---|---|---|---|---|
Duplex 2205 (original) | UNS S31803 astm a815 uns s31803 | Werkstoff 1.4462, F51 | ASTM A182 F51 | ≈ 33–35 |
Duplex 2205 (tighter spec) | UNS S32205 ASTM A815 / SA815 | Werkstoff 1.4462, F60 | ASTM A182 F60 | ≈ 35–36 |
Super duplex 2507 | UNS S32750 astm a815 uns s32750 | Werkstoff 1.4410, F53 | ASTM A182 F53 | ≥ 40 |
PREN = Cr + 3.3 × Mo + 16 × N. It is a quick ranking of pitting resistance, not a guarantee. Real-world performance depends on temperature, chloride level and crevice conditions.
In simple terms, S32205 is the same family as S31803 with a narrower composition window, a minimum of 0.14% nitrogen and slightly higher chromium and molybdenum floors. Most mills now dual-certify plate and pipe to both. If your specification names a hybrid such as “a815 s31803” or “astm a815 s31803”, we confirm the exact UNS and edition with you before quoting so the certificate matches your datasheet.
Looking at higher chloride loads or sour service? Explore our super duplex S32750 / S32760 pipe fittings. Mild service? Stainless steel 316/316L pipe fittings may do the job for less.
Technical Data
Duplex Steel Pipe Fittings Technical Specifications
| Parameter | Details |
|---|---|
| Governing specification | ASTM A815 / ASME SA815 (fittings), ASTM A182 (forged) |
| Grades | UNS S31803, UNS S32205; super duplex UNS S32750 (also S32760) on request |
| Equivalent designations | Werkstoff 1.4462 (2205), 1.4410 (2507); ASTM A182 F51 / F60 / F53 |
| Size range | 1/2″ to 24″ NB (DN15 – DN600); larger on request |
| Wall thickness | SCH 5S, 10S, 40S, 80S, 160, XXS and custom |
| Construction | Seamless (WP-S), welded (WP-W), welded + radiographed (WP-WX), fabricated |
| Dimensional standards | ASME B16.9, B16.28, B16.11, MSS SP-43, BS 4504, BS 1560, BS 10 |
| Bend radius | 1D, 1.5D, 3D, 5D, 6D, 8D, 10D or as per drawing |
| End finish | Beveled for welding, threaded (NPT / BSP), socket-weld |
| Heat treatment | Solution annealed and rapidly quenched |
Duplex Steel Buttweld Fittings
Duplex steel buttweld fittings are the workhorse of process piping. They are welded directly to the pipe, so there are no threaded leak paths, and flow stays smooth through the bend or branch. We manufacture them seamless, welded and fabricated in 1/2″ to 24″ NB, from SCH 5S up to XXS, and in custom radii on drawing.
| Fitting | Variants | Standard | Where it is used |
|---|---|---|---|
| Elbows | 90° / 45° / 180° long radius, short radius, 3D, 5D bends | ASME B16.9, B16.28 | Direction changes in seawater, process and utility lines |
| Tees | Equal and reducing (unequal) | ASME B16.9 | Branch connections, manifolds |
| Reducers | Concentric and eccentric | ASME B16.9 | Size transitions; eccentric for pump suction and drainage |
| End caps | Butt-weld cap | ASME B16.9 | Line termination, vessel heads on small vessels |
| Crosses | Equal and reducing | ASME B16.9 | Four-way branch points where space is tight |
| Stub ends | Long and short pattern, lap joint | ASME B16.9, MSS SP-43 | Used with lap-joint flanges where frequent dismantling is needed |
| Pipe bends | 1.5D, 2D, 3D, 5D, 6D, 8D, 10D | ASME B16.49 / customer drawing | Pigging lines and long-radius runs |
Duplex Steel Forged Fittings
For small-bore, high-pressure lines (NPS 4 and below), duplex steel forged fittings are often the better answer. They are forged to ASTM A182 grades F51, F60 or F53, then machined to ASME B16.11 with socket-weld or threaded ends. Typical pressure classes are 3000#, 6000# and 9000#. If your instrument tapping, sample line or hydraulic circuit is small and heavily loaded, ask us about duplex steel forged fittings.
| Parameter | Buttweld fittings | Forged fittings |
|---|---|---|
| Typical size | 1/2″ to 24″ NB (larger on request) | 1/8″ to 4″ NB |
| Standard | ASTM A815 + ASME B16.9 | ASTM A182 + ASME B16.11 |
| End type | Beveled for butt-welding | Socket-weld or threaded (NPT/BSP) |
| Rating basis | Pipe schedule | Pressure class (3000# / 6000# / 9000#) |
| Best for | Main process and seawater lines | Small-bore, high-pressure, instrument and sample lines |
Need more than fittings? We also make duplex steel pipes, duplex steel flanges, duplex steel tube fittings and duplex steel valves, so your complete duplex package can come from one mill lineage instead of three vendors.
Duplex Steel Pipe Fittings Chemical Composition (%)
Element | UNS S31803 | UNS 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 |
Manganese (Mn) max | 2.00 | 2.00 |
Silicon (Si) max | 1.00 | 1.00 |
Carbon (C) max | 0.030 | 0.030 |
Phosphorus (P) max | 0.030 | 0.030 |
Sulfur (S) max | 0.020 | 0.020 |
Copper (Cu) max | – | – |
Duplex Steel Pipe Fittings Mechanical Properties
| Property | UNS S31803 | UNS S32205 | UNS S32750 |
|---|---|---|---|
| Tensile strength | 620 MPa (90 ksi) | 655 MPa (95 ksi) | 800 MPa (116 ksi) |
| Yield strength (0.2% offset) | 450 MPa (65 ksi) | 450 MPa (65 ksi) | 550 MPa (80 ksi) |
| Elongation | 25% | 25% | 15% |
| Hardness (max) | ≈ 290 HBW / 31 HRC | ≈ 293 HBW / 31 HRC | ≈ 310 HBW / 32 HRC |
Values reflect typical ASTM A815 / A790 requirements. The exact limits depend on the edition and class on your purchase order, and we confirm them against the standard before every quote.
Duplex Steel Pipe Fittings Physical Properties
Dimension and Weight Chart (ASME B16.9, SCH 40S, selected sizes)
NPS (in) | O.D. (mm) | 90° LR elbow, centre-to-end (mm) | 45° elbow, centre-to-end (mm) | Equal tee, centre-to-end (mm) | Wall SCH 40S (mm) | Approx. 90° elbow weight (kg) |
|---|---|---|---|---|---|---|
1/2 | 21.3 | 38 | 16 | 25 | 2.77 | 0.04 |
1 | 33.4 | 38 | 22 | 38 | 3.38 | 0.15 |
2 | 60.3 | 76 | 35 | 64 | 3.91 | 0.65 |
3 | 88.9 | 114 | 51 | 86 | 5.49 | 2.01 |
4 | 114.3 | 152 | 64 | 105 | 6.02 | 3.82 |
6 | 168.3 | 229 | 95 | 143 | 7.11 | 10.1 |
8 | 219.1 | 305 | 127 | 178 | 8.18 | 20.2 |
10 | 273.1 | 381 | 159 | 216 | 9.27 | 35.9 |
12 | 323.9 | 457 | 190 | 254 | 9.53 | 52.7 |
Weights are theoretical, calculated at 7.8 g/cm³ for a long-radius elbow, and will vary with wall tolerance and end bevel. Full charts up to 24″ NB and other schedules are available in our technical catalog.
Matching Pipe: A790, S31803 and S32750
A fitting is only half the joint. For ferritic/austenitic stainless, the pipe that normally matches these fittings is made to ASTM A790 (seamless and straight-seam welded). So when buyers ask us for an a790 pipe, we usually quote the fittings and pipe together so wall thickness, grade and heat treatment line up at the weld. We supply s31803 pipe and S32205 for general duplex service, and s32750 pipe where super duplex is specified. Both are available through our duplex steel pipes range.
Pipe item | Specification | Mates with fitting |
|---|---|---|
a790 pipe, seamless / welded | ASTM A790 / SA790 | ASTM A815 WP-S / WP-W / WP-WX |
s31803 pipe | ASTM A790 UNS S31803 | ASTM A815 UNS S31803 |
s32750 pipe | ASTM A790 UNS S32750 | ASTM A815 UNS S32750 |
Dimension Chart (ASME B16.9, Select Sizes)
| NPS (inch) | O.D. (mm) | 90° LR Elbow C-to-F (in) | 45° LR Elbow C-to-F (in) | Equal Tee C-to-E (in) |
|---|---|---|---|---|
| 1/2 | 21.3 | 1 1/2 | 5/8 | 1 1/2 |
| 1 | 33.4 | 1 1/2 | 7/8 | 1 1/2 |
| 2 | 60.3 | 3 | 1 3/8 | 3 |
| 4 | 114.3 | 6 | 2 1/2 | 4 1/2 |
| 6 | 168.3 | 9 | 3 3/4 | 6 |
| 8 | 219.1 | 12 | 5 | 7 |
| 12 | 323.9 | 18 | 7 1/2 | 10 |
Approximate Weight Chart (per piece, 90° Elbow)
| Size (inch) | Weight (kg) |
|---|---|
| 1/2 | 0.08 |
| 3/4 | 0.11 |
| 1 | 0.15 |
| 1 1/4 | 0.25 |
| 1 1/2 | 0.39 |
| 2 | 0.66 |
| 2 1/2 | 1.37 |
| 3 | 2.19 |
| 4 | 4.12 |
| 5 | 6.89 |
| 6 | 10.7 |
| 8 | 21.6 |
| 10 | 37.0 |
| 12 | 61.0 |
| 16 | 121.0 |
| 24 | 377.0 |
Full dimension and tolerance charts up to 48″ NB are available in our downloadable technical PDF and price list.
Where These Duplex Steel Pipe Fittings Actually Get Used
Our enquiries for duplex steel fittings follow a clear pattern. Almost every duplex order comes from a place where chlorides, pressure or both have already caused trouble once.
Industry | Typical lines | Why duplex fits |
|---|---|---|
Offshore oil and gas | Firewater, seawater lift, produced water, flowlines | Chloride SCC resistance and weight savings from thinner walls |
Desalination | RO high-pressure feed, brine rejection, intake | Pitting resistance in warm, high-salinity water |
Petrochemical and chemical | Process lines with chlorides, acids, CO₂ / H₂S | Good general corrosion resistance, NACE-compliant supply |
Marine and shipbuilding | Ballast, scrubber, cooling water | Strength and seawater resistance with lower weight |
Pulp and paper | Digesters, bleach plant, white liquor | Resistance to chloride-bearing and caustic streams |
Power and FGD | Flue-gas desulfurisation, cooling water | Handles acidic, chloride-rich condensate |
Water and wastewater | Treatment plants, pressure mains | Long life with minimal maintenance |
Heat exchangers | Shell-side and tube-side piping | High strength and good stress-corrosion performance |
Duplex is not the ceiling, though. For deeper offshore work, sour service or extreme chloride load, step up to our super duplex pipe fittings in UNS S32750.
Duplex 2205 vs Stainless Steel 316L: Which One Do You Actually Need?
Almost every enquiry we get eventually circles back to this question, so let’s just answer it plainly instead of dancing around it:
Factor | Duplex 2205 (S31803 / S32205) | Super duplex 2507 (S32750) |
|---|---|---|
Microstructure | Austenitic–ferritic | Austenitic–ferritic (higher alloy) |
Min. yield strength | 450 MPa | 550 MPa |
Min. tensile strength | 620–655 MPa | 800 MPa |
PREN (approx.) | ≈ 35 | ≥ 40 |
Chloride SCC resistance | Very good | Excellent |
Seawater suitability | Good with ambient / moderate temperatures | Excellent, even warmer seawater |
Service temperature | −50 °C to 300 °C | −50 °C to 300 °C |
Our honest take: if the line is genuinely chloride-heavy (seawater, produced water, brine), duplex pays for itself in avoided downtime. If your service is mild, don’t overspend. 316L is still the sensible pick. And if your design temperature is above 300 °C or below −50 °C, duplex is the wrong tool entirely, because long exposure to higher temperatures can cause embrittlement and cryogenic toughness is limited.
Not Sure Which Grade Is Right for Your Line?
If your service is… | Start with… |
|---|---|
Seawater, brackish or produced water at moderate temperature | Duplex 2205 (S31803 / S32205) |
High chloride, higher temperature seawater, or sour service | Super duplex 2507 (S32750) |
Mild chlorides, ambient temperature, no stress corrosion risk | 316L may be enough |
Temperature above 300 °C or cryogenic | Consider austenitic or nickel alloys instead |
How We Manufacture and Test Every Batch
| Stage | What happens | Why it matters |
|---|---|---|
| 1. Raw material check | Incoming pipe and plate checked by PMI against mill certificates traceable to EN 10204 3.1 | Wrong grade in means wrong grade out. We catch it here. |
| 2. Forming | Hot or cold press forming, pushing, bending or forging depending on fitting | Forming route changes the final grain and thickness distribution |
| 3. Solution annealing | Heated to a controlled temperature (typically 1020–1100 °C) and rapidly quenched | Restores the 50/50 phase balance and dissolves harmful phases |
| 4. Pickling and passivation | Acid cleaning to remove scale and restore the passive layer | Protects corrosion resistance |
| 5. Testing | Ferrite measurement, hydrostatic test, intergranular corrosion test, radiography and ultrasonic checks as per order | Proves the product, not just the paperwork |
| 6. Final inspection | Dimensional check, marking, packing; third-party inspection through Lloyd’s, TUV or Bureau Veritas on request | Clean handover and audit-ready documents |
We run these checks not because a checklist demands it, but because a certificate is the paperwork a buyer needs when something goes wrong two years later and someone asks for traceability.
Quality Tests Available
Test | Purpose | Status |
|---|---|---|
PMI (XRF / OES) | Verifies grade chemistry on every piece | Standard |
Ferrite content | Confirms phase balance (commonly 35–65% ferrite) | Standard |
Tensile, yield, elongation | Mechanical conformance to A815 / A790 | Standard |
Hardness (HBW / HRC) | Checks heat treatment and absence of cold-work damage | Standard |
Hydrostatic test | Pressure integrity | Standard |
Intergranular corrosion test | Corrosion performance after heat treatment | As per order |
Radiography / ultrasonic / dye penetrant | Weld and body integrity | As per order (WP-WX class) |
Microstructure / ASTM A923 | Detects harmful intermetallic phases | On request |
Third-party inspection | Independent witness and EN 10204 3.2 certificate | On request |
CERTIFICATIONS & STANDARDS
Certification / Standard | Scope |
|---|---|
ISO 9001:2015 | Quality management |
ISO 14001:2015 | Environmental management |
ISO 45001:2018 | Occupational health and safety |
ASTM A815 / ASME SA815 | Manufacturing standard for duplex fittings |
ASTM A182 / ASME SA182 | Forged duplex fittings and flanges |
ASME B16.9, B16.11, B16.28, MSS SP-43 | Dimensional standards |
NACE MR0175 / ISO 15156 | Sour service compliance |
EN 10204 3.1 | Mill test certification (3.2 on request) |
Third-party inspection | Lloyd’s Register, TUV, Bureau Veritas (on request) |
Types of Duplex Steel Pipe Fittings
Duplex Steel Pipe Fittings Price List
Item | Price in India (INR) | Price in USD | Price in UAE (AED) |
|---|---|---|---|
Duplex Steel Elbow (per piece) | ₹922 | $19.33 | AED 46.61 |
Duplex Steel Elbow (budget size) | ₹452 | $5.85 | AED 26.50 |
Duplex Pipe Fittings (average, per piece) | ₹2,460 | $28.21 | AED 107.27 |
Duplex Steel Weld Fittings | ₹1,298 | $20.00 | AED 68.44 |
Duplex Steel 90° Elbow | ₹1,767 | $29.78 | AED 74.30 |
Duplex Reducer (per kg) | ₹492 | $9.85 | AED 29.50 |
Duplex Steel 45° Elbow | ₹5,621 | $65.17 | AED 257.30 |
Duplex Steel Bend | ₹1,304 | $17.82 | AED 56.11 |
These are indicative figures that move with schedule, seamless-versus-welded construction, and order quantity. Send us your actual size list and we’ll come back with firm, size-wise pricing.
People Ask About Duplex Steel Pipe Fittings Manufacturer
Duplex 2205 Pipe Fittings are high-performance duplex stainless steel fittings available in grades UNS S31803 and UNS S32205. They combine excellent strength, corrosion resistance, and durability for industrial applications.
S31803 material is a duplex stainless steel grade known for superior corrosion resistance, high tensile strength, and long-lasting performance in chemical, hydraulic, and high-temperature environments.
UNS S32205 fittings offer exceptional strength, resistance to galling, leak-proof performance, and stability under high temperatures. They are suitable for chemical, marine, and industrial applications.
They are widely used in oil & gas, chemical processing, marine environments, medical devices, and high-temperature hydraulic systems.
Ready to Specify Duplex Steel Pipe Fittings?
Whether you need standard duplex steel fittings from stock sizes or custom bends made to your drawing, tell us your grade, size list and delivery location, and we will respond with a firm quote and lead time within 24 hours. Not sure whether you need 2205, S32750 or just 316L? Talk to us first. We would rather help you pick the right material than sell you the wrong one.
Email: info@kalpatarupipingsolution.com | Phone: +91 22-66337137 | Mumbai, India
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