Duplex Steel Pipe Fittings Manufacturer, Supplier & Global Exporter
Amardeep Steel Centre manufactures and exports Duplex Steel Fittings in ASTM A815 / ASME SA815 and ASME B16.9 specifications, covering buttweld, forged, socket weld, and duplex tube fittings in UNS S31803 and UNS S32205. With over 40 years in the steel supply chain (est. 1984) and active export programmes to the Gulf, Europe, and South-East Asia, we supply duplex stainless steel pipe fittings that meet full traceability requirements under EN 10204/3.1B. All shipments carry Mill Test Certificates, and third-party inspection (SGS, BV, TÜV, Lloyds) is available on request.
Amardeep Steel Centre manufactures and exports duplex steel fittings in ASTM A815 / ASME SA815 and ASME B16.9 acceptable buttweld, forged, socket weld, and duplex tube fittings of UNS S31803 and UNS S32205. We have more than 40 years of experience in the steel supply chain (est. 1984) and run active export programmes to the Gulf, Europe, and South-East Asia, where we supply duplex stainless steel pipe fittings complying with full traceability requirements under EN 10204/3.1B. Every shipment is accompanied by Mill Test Certificates and third-party inspection (SGS, BV, TUV, Lloyds) can be requested.
Table of Contents
- Duplex Steel Pipe Fittings Manufacturer
- What are Duplex Steel Fittings?
- Duplex Steel Pipe Fittings by Type
- Duplex Steel Tube Fittings
- Types of Duplex Steel Fittings
- Specifications & Standards
- Chemical Composition
- Mechanical Properties
- Equivalent Grades
- Key Properties
- Welding & Fabrication
- Industries & Applications
- Why Choose Amardeep Steel
- Related Products
- FAQs
What are Duplex Steel Fittings?
Duplex Steel Fittings are pipe fittings that are made using duplex stainless steel; a two-phase alloy that contains about 50% ferrite and 50% austenite microstructure. These fittings, including UNS S31803 and UNS S32205 (Duplex 2205), are made to be as strong as ferritic steels and also as corrosive and tough as austenitic.
The dual-phase microstructure provides twice the yield strength of standard 304/316 austenitic steels, exceptional resistance to chloride stress corrosion cracking (SCC), and a Pitting Resistance Equivalent Number (PREN) of 34 and above with UNS S32205 which is why duplex pipe fittings are the most recommended over austenitic grades in aggressive chloride, seawater, and high-pressure environments.
UNS S31803 — Duplex 2205
The original Duplex 2205 designation. Allows a broader nitrogen range of 0.08–0.20%. Widely specified across legacy oil & gas and chemical plant projects. WNR 1.4462.
UNS S32205 — Duplex 2205 (Modern)
The preferred modern designation. Tightens nitrogen to 0.14–0.20% and molybdenum to 3.0–3.5%, improving pitting resistance. Same WNR 1.4462. Recommended for new projects.
Duplex Steel Pipe Fittings by Type
Amardeep Steel supplies duplex steel pipe fittings across two main manufacturing routes. Select a product type below for detailed specifications, dimensions, and grades.
Duplex Steel Buttweld Fittings
ASTM A815 / ASME SA815. ASME B16.9 dimensions. Size range ½" NB to 48" NB. Elbows, tees, reducers, caps, stub ends, crosses.
Duplex Steel Forged Fittings
ASTM A182 / ASME SA182. ASME B16.11 dimensions. Socket weld & threaded. Class 3000, 6000, 9000. Sizes ½" to 4".
Duplex Steel Tube Fittings (Instrumentation Grade)
Amardeep Steel supplies UNS S31803 and UNS S32205 duplex tube fittings for instrumentation and high-pressure lines, including ferrule fittings, compression fittings, union elbows, male connectors, and female connectors. Rated for working pressures up to 10,000 PSI. These are suitable for subsea instrumentation, offshore control lines, and chemical injection systems.
Duplex Steel Fittings in UNS S31803
- ASTM A815 / A182 compliant
- N range: 0.08–0.20%
- Mo range: 2.5–3.5%
- PREN: ≥ 32
- Legacy and general service grade
Duplex Steel Fittings in UNS S32205
- ASTM A815 / A182 compliant
- N range: 0.14–0.20% (tighter)
- Mo range: 3.0–3.5% (tighter)
- PREN: ≥ 34
- Preferred modern designation
Types of Duplex Steel Fittings
Duplex Steel Caps
End caps for sealing pipe ends in high-pressure duplex stainless steel pipeline systems.
Duplex Steel Reducers
Concentric and eccentric reducers join pipes of different diameters under high pressure.
Duplex Steel Tees
Equal and unequal tees for splitting or merging of fluid flow in duplex pipe systems.
Duplex Steel Elbows
45° and 90° Long & Short Radius elbows for directional changes in piping systems.
Duplex Crosses
Four-way cross fittings for complex multi-directional piping configurations.
Duplex Tube Fittings
Precision instrumentation fittings for high-pressure tubing up to 10,000 PSI.
Duplex Stub Ends
Used with lap-joint flanges allowing easy rotation for bolt-hole alignment.
Duplex Pipe Fittings Specifications & Standards
| Parameter | Details |
|---|---|
| Material Standard | ASTM A815 / ASME SA815 (Buttweld) | ASTM A182 / ASME SA182 (Forged) |
| Grades | UNS S31803, UNS S32205 (Duplex 2205), DIN 1.4462, UNS S32750, UNS S32760 (Super Duplex) |
| Dimensional Standards | ASME/ANSI B16.9, ANSI B16.28, MSS-SP-43, MSS-SP-75, B16.11 |
| Size Range | ½" NB to 48" NB (Buttweld) | ½" to 4" (Forged / Threaded / Socket Weld) |
| Wall Thickness | SCH 10, SCH 20, SCH 40, SCH 80, SCH 160, XXS |
| End Type | Beveled End (BE), Plain End (PE), Threaded, Socket Weld |
| Form | Seamless & Welded (ERW / EFW) |
| Pressure Rating | Class 3000, 6000, 9000 (Forged Fittings) |
| Test Certificates | EN 10204 / 3.1B | Raw Material Certificate | 100% Radiography | PMI |
Looking for ASTM A815 Duplex Steel Fittings in S31803 or S32205?
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Request a Quote →Duplex Steel Fittings Chemical Composition
UNS S32205 Pitting Resistance Equivalent Number — Superior to austenitic 316L (PREN ~24). Qualifies duplex pipe fittings for chloride-rich seawater and chemical service environments where 316L is excluded by pitting risk.
| Grade | UNS No. | Cr % | Ni % | Mo % | N % | C % Max |
|---|---|---|---|---|---|---|
| Duplex 2205 | S31803 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | 0.030 |
| Duplex 2205 (Modified) | S32205 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | 0.030 |
| Super Duplex 2507 | S32750 | 24–26 | 6–8 | 3–5 | 0.24–0.32 | 0.030 |
| Super Duplex Zeron 100 | S32760 | 24–26 | 6–8 | 3–4 | 0.20–0.30 | 0.030 |
Duplex Stainless Steel Pipe Fittings Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation % (Min) | Hardness (HRC Max) | PREN |
|---|---|---|---|---|---|
| Duplex 2205 (S31803) | 620 Min | 448 Min | 25 | 31 | ≥ 32 |
| Duplex 2205 (S32205) | 620 Min | 450 Min | 25 | 31 | ≥ 34 |
| Super Duplex 2507 (S32750) | 795 Min | 550 Min | 15 | 32 | ≥ 41 |
| Super Duplex Zeron 100 (S32760) | 750 Min | 550 Min | 25 | 32 | ≥ 40 |
Duplex Tube Fittings Equivalent Grades
| Grade | UNS | EN / DIN | W. Nr. | Common Name |
|---|---|---|---|---|
| Duplex 2205 | S31803 / S32205 | 1.4462 | 1.4462 | Duplex 2205 |
| Super Duplex 2507 | S32750 | 1.4410 | 1.4410 | SAF 2507 / F53 |
| Zeron 100 | S32760 | 1.4501 | 1.4501 | F55 / Zeron 100 |
| Lean Duplex | S32101 | 1.4162 | 1.4162 | LDX 2101 |
Key Properties of Duplex Stainless Steel Pipe Fittings
- Twice the yield strength of standard austenitic stainless steels
- Superior chloride stress corrosion cracking (SCC) resistance
- Outstanding pitting and crevice corrosion resistance (PREN ~35)
- Excellent resistance to erosion and abrasion
- Good weldability with correct procedures and filler metals
- Low thermal expansion coefficient for dimensional stability
- High thermal conductivity vs. austenitic grades
- Cost-effective: thinner walls due to higher yield strength
- Resistant to sulphide stress corrosion cracking in sour service
- Suitable for cyclic loading and fatigue-critical applications
- Good machinability and formability
- Resistant to organic acids (formic, acetic) in super duplex grades
Welding & Fabrication of Duplex Steel Fittings
Duplex steel pipe fittings can be welded by all standard arc welding processes (GTAW, GMAW, SMAW, SAW). Key considerations for maintaining duplex microstructure and corrosion resistance:
Do not use oxyacetylene welding — flame welding introduces excessive heat and carbon, disrupting the ferritic-austenitic phase balance and reducing corrosion resistance.
- Filler metal: Use ER2209 (MIG/TIG) for UNS S31803 / S32205. This over-alloyed filler compensates for nitrogen loss during welding and maintains the duplex microstructure in the weld zone.
- Post-weld: Solution annealing at 1080°C followed by rapid water quench is recommended where maximum corrosion resistance is required. Heat input should be controlled to avoid sigma phase precipitation (avoid temperatures in the 700–900°C range for extended periods).
Industries & Applications of Duplex Steel Pipe Fittings
Duplex steel pipe fittings are specified across industries where standard austenitic grades (304 / 316) fall short on strength or chloride resistance. Our duplex pipe fittings and duplex stainless steel pipe fittings serve some of the most demanding industrial environments globally:
- Oil & Gas: Wellhead piping, subsea flowlines, offshore risers where chloride stress corrosion cracking (CSCC) is a failure risk.
- Chemical Processing: Heat exchangers, pressure vessels, and reactor piping handling acids, chlorides, and aggressive media.
- Desalination & Water Treatment: High-pressure RO plant pipework; duplex fittings outperform 316L in seawater environments.
- Pulp & Paper Mills: Bleach plant piping (hot chloride service); duplex outperforms 316L and 317L on pitting resistance.
- Marine & Shipbuilding: Propeller shafts, pump housings, and seawater intake lines in offshore and marine structures.
- Power Generation: FGD scrubber systems and cooling water circuits. High-pressure steam and condensate service.
- Petrochemical Plants: Process piping in refinery and petrochemical units handling sour gas and high-chloride streams.
- Subsea Systems: Instrumentation lines, control umbilicals, and high-pressure tube fittings for subsea wellhead control.
- Pharmaceutical & Food: High-purity process lines where both corrosion resistance and hygienic surface finish are required.
Why Choose Amardeep Steel for Duplex Steel Fittings?
Amardeep Steel Centre is a trusted name in the global supply of high-grade duplex steel fittings and duplex tube fittings. Here’s what sets us apart:
- Mill-certified, traceable raw materials from top global mills
- Full compliance with ASTM, ASME, DIN, ISO & JIS standards
- 100% visual inspection; PMI, hydrostatic, IGC, radiography testing available on request
- Fast delivery from bulk stock maintained across all grades
- ISO 9001:2015 certified manufacturing process. PED / IBR certifications available on request
- TPI available via SGS, BV, TÜV, and Lloyds. Inspection waiver documents supplied
- Competitive pricing with no compromise on quality
- Experienced technical team for material selection support
- Global export to 50+ countries
- Safe, damage-proof packaging for transit reliability
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Get a Quote →Related Products
- Duplex Steel Pipes & Tubes
- Duplex Steel Plates, Sheets & Coils
- Duplex Steel Bars, Rods & Wires
- Duplex Steel Forged Fittings
- Duplex Steel Flanges
- Duplex Steel Buttweld Fittings
- Duplex Steel Fasteners
- Duplex Steel Coil Tube
Frequently Asked Questions — Duplex Steel Fittings
What is the difference between UNS S31803 and UNS S32205 duplex steel fittings?
Both are Duplex 2205 grade alloys under the WNR 1.4462 designation. UNS S31803 allows a broader nitrogen range (0.08–0.20%); UNS S32205 tightens nitrogen to 0.14–0.20% and molybdenum to 3.0–3.5%, improving pitting resistance (PREN ≥ 34 vs ≥ 32 for S31803). S32205 is now the preferred modern designation and is recommended for new project specifications.
What grades of Duplex Steel Fittings does Amardeep Steel supply?
Amardeep Steel supplies Duplex Steel Fittings in grades UNS S31803, UNS S32205 (Duplex 2205), DIN 1.4462, and Super Duplex grades UNS S32750 (SAF 2507/F53) and UNS S32760 (Zeron 100/F55). Lean duplex grades such as S32101 are also available on request.
What standards are Duplex Pipe Fittings manufactured to?
Our Duplex Steel Pipe Fittings comply with ASTM A815 / ASME SA815 for buttweld fittings, and ASTM A182 / ASME SA182 for forged fittings. Dimensional standards include ASME/ANSI B16.9, B16.11, B16.28, and MSS-SP-43.
What types of Duplex Steel Fittings are available?
We offer Duplex Steel Buttweld Fittings (45° and 90° elbows, equal and reducing tees, concentric and eccentric reducers, end caps, stub ends, and crosses) as well as Duplex Steel Forged Fittings (socket weld and threaded elbows, tees, couplings, unions, and bushings). Duplex tube fittings for instrumentation applications are also available.
Can duplex steel fittings be used in seawater service?
Yes. The PREN of UNS S32205 (≥ 34) qualifies it for seawater and chloride service where austenitic grades 304 and 316 are excluded by pitting risk. For highly aggressive offshore and subsea applications, Super Duplex grades (UNS S32750, PREN ≥ 41) are recommended.
What industries use Duplex Stainless Steel Pipe Fittings?
Duplex stainless steel pipe fittings are extensively used in oil and gas pipelines, petrochemical and chemical plants, offshore and marine systems, desalination plants, power generation, pulp and paper mills, water treatment facilities, heat exchangers, and pressure vessel applications.
What is the size range for Duplex Steel Pipe Fittings?
Duplex Steel Buttweld Pipe Fittings are available from ½" NB to 48" NB in schedules SCH 10 through XXS. Forged duplex fittings (socket weld and threaded) are available from ½" to 4" in Class 3000, 6000, and 9000 pressure ratings.
Does Amardeep Steel export Duplex Pipe Fittings internationally?
Yes, Amardeep Steel Centre is a global exporter of Duplex Pipe Fittings and Duplex Tube Fittings, supplying clients in the Middle East (UAE, Saudi Arabia, Qatar), Europe, USA, Canada, Africa, and Southeast Asia with full export documentation and third-party inspection support.
