Duplex Steel Pipes & Tubes Manufacturer, Exporter & Suppliers, Duplex Steel Seamless Pipes & Tubes, Duplex Steel Welded Pipes & Tubes, ERW Pipes Suppliers in India
Duplex steel pipes and tubes are made of a combination of austenitic and ferritic stainless steel microstructures, which offer them better strength and resistance to corrosion as compared with conventional carbon steel pipes. They are a perfect fit in the applications that need lightweight, but high-strength materials due to their high strength-to-weight ratio. Meanwhile, they are corrosion resistant and can be used in very corrosive surroundings.
Duplex pipes resist localized corrosion like pitting and crevice corrosion which is why they are highly desirable compared to the traditional stainless steel grades in chloride environments. Also, they have good weldability
may be bent into tight radius bends without a loss of mechanical properties and corrosion resistance. This renders duplex stainless steel pipes to be used in onshore and offshore pipelines among other industrial applications that demand high reliability.
The duplex steel pipe is used for high-pressure and high-flow applications. DSS pipes have great application in industries that demand high levels of strength and resistance to corrosion. The main strengths are that it is stronger than austenitic and ferritic grades, it possesses better corrosion resistance, it has less pressure loss, and it is cost-effective because of lower material thickness needs. They also provide better flow performance in challenging applications.
Duplex Pipe Supplier
Amardeep Steel is a leading manufacturer, exporter, and supplier of Duplex Stainless Steel Pipes and Tubes in India. We produce duplex pipes in three categories: standard duplex, super duplex, and lean duplex stainless steel pipes and tubes, each offering different levels of strength and corrosion resistance based on application requirements.
The duplex steel pipe is almost twice as strong as conventional austenitic stainless steel grades. These pipes offer excellent corrosion resistance, stress corrosion cracking resistance, and high temperature strength. Duplex stainless steel seamless and welded pipes are available in thinner wall thicknesses due to their high yield strength, making them cost-effective and efficient.
Amardeep Steel is an ISO 9001:2015 certified manufacturer, exporter, and supplier of duplex stainless steel pipes and tubes with over 25 years of industry experience. We supply to EPC contractors, refineries, petrochemical plants, shipbuilders, and OEM fabricators across more than 80 countries worldwide.
Duplex Stainless Steel Pipe Grades
Amardeep Steel stocks and supplies duplex pipe in the following standard and super duplex grades:
Grade 2205 (UNS S31803 / UNS S32205)
The most widely used duplex grade. Grade 2205 contains 22 percent chromium, 5 percent nickel, and 3 percent molybdenum. It offers excellent resistance to pitting and stress corrosion cracking and is used across oil and gas pipelines, chemical vessels, and heat exchanger applications. Available as ASTM A790 seamless and welded pipe and ASTM A789 tubes.
Grade 2507 (UNS S32750) Super Duplex
Super duplex grade 2507 contains 25 percent chromium, 7 percent nickel, and 4 percent molybdenum, giving it a Pitting Resistance Equivalent Number (PREN) of 43 or above. It is specified for environments with higher chloride concentrations, elevated temperatures, and higher operating pressures, including deepwater offshore risers and seawater piping systems.
Grade 2304 (UNS S32304) Lean Duplex
Grade 2304 is a lean duplex grade with lower nickel content that reduces material cost while maintaining good mechanical strength and acceptable corrosion resistance. It is suited for structural applications, bridge construction, and storage tanks where cost efficiency is a priority.
Grade S32760 (UNS S32760 / 1.4501) Super Duplex
UNS S32760 is a super duplex grade with added tungsten and copper that further enhances its corrosion resistance in highly aggressive environments. It is commonly used in oil and gas processing, desalination systems, and chemical injection lines.
How Duplex Steel Pipe Is Manufactured
Understanding the manufacturing process helps buyers confirm quality assurance at the source. Amardeep Steel produces duplex pipes through the following methods:
Seamless Duplex Pipe Manufacturing
Seamless duplex pipes are produced by hot extrusion or cold drawing of solid billets. No weld seam is present, making seamless pipe the preferred choice for high-pressure and high-temperature applications. After forming, pipes are solution annealed and water quenched to restore the duplex microstructure.
Welded and ERW Duplex Pipe Manufacturing
Welded duplex pipes are formed by rolling stainless steel strips into a tubular shape and joining the longitudinal seam using the TIG (Tungsten Inert Gas) welding process. Submerged arc or plasma welding is used for larger diameters. After welding, pipes are solution annealed to remove weld-induced phase imbalance.
EFW Duplex Pipe Manufacturing
Electric Fusion Welded (EFW) pipe is produced for larger diameter applications, typically above DN 400. The fusion weld is followed by full heat treatment and 100 percent radiographic testing to ensure integrity.
Duplex Steel Pipe Specification
The following table covers the primary specifications applicable to duplex stainless steel pipes and tubes supplied by Amardeep Steel:
| Parameter | Details |
|---|---|
| Applicable Standards | ASTM A790 / ASME SA790 | ASTM A789 / ASME SA789 | ASTM A928 | ASTM A999 / ASME SA999 |
| Pipe OD Range | Seamless: 6.00mm to 250mm | Welded: 5.0mm to 1219.2mm |
| Wall Thickness | 0.3mm to 50mm |
| Tube OD Range | 6.35mm to 152mm |
| Pipe Schedule | SCH 5, SCH 10, SCH 40, SCH 80, SCH 160, SCH XS, SCH XXS |
| Pipe Forms | Round, Square, Rectangular, U-Shape, Coiled, Pancake Coils, Straight |
| Pipe Types | Seamless, Welded, ERW, EFW, CDW, DOM, Fabricated |
| Surface Finish | AP (Annealed and Pickled), 2B, BA, No.1, No.4, Polished, Mirror, HL |
| Length | Single Random, Double Random, Fixed Cut-to-Length |
| End Type | Plain End, Beveled End, Threaded |
| Applicable Standards | EN, ASTM, ASME, AISI, GB, JIS, DIN |
| Value Added Services | Bending, Pickling, Annealing, Polishing, Machining, Drawing, Expansion |
Duplex Steel Pipe Chemical Composition
| Grade | C max | Mn max | P max | S max | Si max | Ni | Cr | Mo | N | Cu |
|---|---|---|---|---|---|---|---|---|---|---|
| S31803 | 0.03 | 2.00 | 0.03 | 0.02 | 1.00 | 4.5 to 6.5 | 21.0 to 23.0 | 2.5 to 3.5 | 0.08 to 0.20 | Nil |
| S32205 | 0.03 | 2.00 | 0.03 | 0.02 | 1.00 | 4.5 to 6.5 | 22.0 to 23.0 | 3.0 to 3.5 | 0.14 to 0.20 | Nil |
| S32750 | 0.03 | 1.20 | 0.035 | 0.02 | 0.80 | 6.0 to 8.0 | 24.0 to 26.0 | 3.0 to 5.0 | 0.24 to 0.32 | 0.5 |
| S32760 | 0.05 | 1.00 | 0.03 | 0.01 | 1.00 | 6.0 to 8.0 | 24.0 to 26.0 | 3.0 to 4.0 | 0.20 to 0.30 | 0.50 to 1.00 |
Duplex Steel Pipe Mechanical Properties
| Grade | Tensile Strength Min | Yield Strength Min | Elongation % Min | Hardness HB Max |
|---|---|---|---|---|
| S31803 | 620 MPa (90 ksi) | 450 MPa (65 ksi) | 25% | 290 |
| S32205 | 655 MPa (95 ksi) | 450 MPa (65 ksi) | 25% | 290 |
| S32750 | 800 MPa (116 ksi) | 550 MPa (80 ksi) | 15% | 300 |
| S32760 | 750 MPa (109 ksi) | 550 MPa (80 ksi) | 25% | 300 |
Duplex Steel Pipe vs Austenitic Stainless Steel: Key Differences
Procurement teams frequently evaluate duplex pipe against SS 316L or SS 304 alternatives. The table below highlights the key technical differences:
| Property | Duplex Grade 2205 | Austenitic SS 316L |
|---|---|---|
| Tensile Strength | 655 MPa Min | 485 MPa Min |
| Yield Strength | 450 MPa Min | 170 MPa Min |
| Chloride SCC Resistance | Excellent | Moderate |
| Pitting Resistance (PREN) | 34 to 38 | 24 to 27 |
| Thermal Conductivity | Higher (better for heat transfer) | Lower |
| Cost vs Performance | Lower nickel content, better value in aggressive environments | Higher nickel, higher cost in corrosive service |
| Wall Thickness Required | Thinner walls possible due to higher yield strength | Thicker walls required |
International Equivalent Grades for Duplex Stainless Steel Pipe
When sourcing duplex pipe for international projects, procurement specifications may reference different national standards. The following equivalences are commonly accepted:
| UNS Grade | EN / DIN Grade | ISO | Common Name |
|---|---|---|---|
| S31803 | 1.4462 | ISO 15156 | Duplex 2205 |
| S32205 | 1.4462 | ISO 15156 | Duplex 2205 (refined) |
| S32750 | 1.4410 | ISO 15156 | Super Duplex 2507 |
| S32760 | 1.4501 | ISO 15156 | Super Duplex Zeron 100 |
| S32304 | 1.4362 | ISO 15156 | Lean Duplex 2304 |
Duplex Steel Pipe Sizes and Weight Chart
The table below lists common duplex pipe sizes with outer diameter, wall thickness, schedule, and weight per meter:
| Pipe OD (mm) | Wall Thickness (mm) | Size (in) | Schedule | Weight (kg/m) |
|---|---|---|---|---|
| 13.72 | 1.65 | 1/4" | 10S | 0.50 |
| 13.72 | 2.24 | 1/4" | 40S | 0.64 |
| 21.34 | 2.77 | 1/2" | 40S | 1.29 |
| 21.34 | 3.73 | 1/2" | 80S | 1.65 |
| 33.40 | 3.38 | 1" | 40S | 2.54 |
| 33.40 | 4.55 | 1" | 80S | 3.29 |
| 48.26 | 3.68 | 1 1/2" | 40S | 4.11 |
| 60.33 | 3.91 | 2" | 40S | 5.52 |
| 60.33 | 5.54 | 2" | 80S | 7.60 |
| 88.90 | 5.49 | 3" | 40S | 11.47 |
| 114.30 | 6.02 | 4" | 40S | 16.32 |
| 168.28 | 7.11 | 6" | 40S | 28.69 |
| 219.08 | 8.18 | 8" | 40S | 43.20 |
| 273.05 | 9.27 | 10" | 40S | 63.30 |
| 323.85 | 9.53 | 12" | 40S | 73.82 |
Custom sizes, non-standard wall thicknesses, and cut-to-length orders are available on request for quantities above 2 tons.
Duplex Steel Pipe Applications by Industry
The combination of high yield strength and corrosion resistance makes duplex stainless steel pipes suitable for demanding service environments across multiple industries:
Oil and Gas Industry
Duplex pipe is extensively used in offshore platforms, subsea flowlines, topside piping, and pipeline risers. The resistance to chloride stress corrosion cracking and sour gas environments (H2S) makes grade 2205 and super duplex 2507 the standard choice for high-pressure well applications.
Chemical and Petrochemical Processing
Chemical plants use duplex pipe for reactor circuits, heat exchanger shells, acid handling lines, and process vessels where media contains chlorides, sulfuric acid, or organic acids. The combination of corrosion resistance and pressure-bearing capacity at elevated temperatures reduces total installed cost.
Desalination and Water Treatment Plants
Super duplex grades S32750 and S32760 are the specified materials for seawater intake piping, brine concentration lines, and reverse osmosis pressure vessels in desalination plants. Their PREN values above 40 ensure resistance even in high-temperature seawater environments.
Marine and Shipbuilding
Duplex pipe is used in seawater cooling systems, ballast water treatment units, deck drainage systems, and cargo tank piping on vessels. Its resistance to biofouling and marine corrosion extends service life significantly compared to carbon steel or standard austenitic grades.
Pulp and Paper Industry
Digesters, bleach plant pipelines, chemical recovery systems, and washing equipment in pulp mills operate with highly corrosive media including chlorine compounds, caustic soda, and black liquor. Duplex and super duplex pipes provide the corrosion resistance required in these environments.
Heat Exchangers and Condensers
The higher thermal conductivity and yield strength of duplex steel allows thinner tube walls in heat exchanger bundles, increasing heat transfer efficiency while reducing material cost. Amardeep Steel specializes in large diameter duplex heat exchanger and condenser tubes.
Pharmaceutical and Food Processing
Duplex stainless steel pipe is used in pharmaceutical fluid transfer systems and food processing lines where corrosion-resistant, hygienic surfaces with smooth bore finishes are required. Bright annealed and electropolished finishes are available.
Types of Duplex Stainless Steel Pipes and Tubes
Amardeep Steel supplies duplex pipe and tube in the following product categories:
Duplex Steel Seamless Pipe (ASTM A790 / ASME SA790)
Produced by hot extrusion without a weld seam, seamless duplex pipe offers the highest pressure integrity. Available in OD from 6mm to 250mm and schedules up to XXS.
Duplex Steel Welded Pipe (ASTM A790 / ASTM A928)
Welded duplex pipes are produced by TIG or plasma welding and are solution annealed after forming. Available from 5mm to 1219.2mm OD with full radiographic testing.
Duplex Steel ERW Pipe
Electric Resistance Welded duplex pipe is available for standard pressure applications where full penetration weld and NDT compliance are confirmed by eddy current or ultrasonic testing.
Duplex Steel Heat Exchanger Tubes
Bright annealed or polished duplex tubes for shell and tube heat exchangers, condensers, and evaporators. Produced to ASTM A789 with strict dimensional tolerances.
Large Diameter Duplex Steel Pipe
Amardeep Steel specializes in large diameter duplex pipe above DN 400 for offshore, petrochemical, and desalination projects. Available as EFW or fabricated pipe with full documentation.
Duplex Steel Pipe Product Range
Explore our specialized duplex pipe product pages for full specifications, datasheets, and pricing:
Quality Assurance and Material Test Certificates
Every order of duplex steel pipe from Amardeep Steel is supplied with full documentation in compliance with EN 10204 3.1 or 3.2 as required. Our standard documentation package includes:
- Material Test Certificate (MTC) as per EN 10204 3.1 and 3.2
- Manufacturer Test Certificate
- 100 percent Radiography Test Report (where applicable)
- Hydrostatic Test Report
- Ultrasonic Test Report
- Heat Treatment Charts
- Form A for Generalized System of Preferences (GSP)
- Third Party Inspection Report (Bureau Veritas, TUV, Lloyd's, SGS on request)
- Laboratory Test Certificate from Government Approved Lab
- Fumigation Certificates for wooden packaging
Duplex Steel Pipe Price and Lead Time
Duplex steel pipe pricing is influenced by grade, size, wall thickness, form (seamless vs welded), order quantity, and current nickel and molybdenum market prices. Amardeep Steel offers:
- Competitive ex-works pricing direct from manufacturer
- Up to 10 to 15 percent cost advantage over stockists for quantities above 2 tons
- Custom mill runs available for quantities above 10 tons
- Ready stock for standard grades and sizes with immediate dispatch
- Lead times of 2 to 4 weeks for standard sizes; 6 to 10 weeks for non-standard or large diameter
Contact our sales team with your RFQ including grade, size, schedule, quantity, and delivery destination for a same-day indicative price.
Frequently Asked Questions About Duplex Steel Pipes
What is the wall thickness of a duplex pipe?
Duplex steel pipes are available in wall thicknesses ranging from 0.3mm to 50mm. For round seamless duplex pipes, OD ranges from 6mm to 630mm with wall thicknesses from 0.5mm to 30mm. Schedule options include SCH 5, SCH 10, SCH 40, SCH 80, SCH 160, SCH XS, and SCH XXS.
What is duplex stainless steel pipe made of?
Duplex pipe is made from an iron-nickel-chromium alloy that has a two-phase microstructure of both ferritic and austenitic stainless steel at room temperature. It contains 19 to 28 percent chromium, up to 5 percent molybdenum, and lower nickel levels compared to standard austenitic grades. This composition provides excellent strength and corrosion resistance.
What grades of duplex stainless steel pipe does Amardeep Steel supply?
Amardeep Steel supplies duplex pipe in all principal grades: standard duplex 2205 (UNS S31803 and S32205), lean duplex 2304 (UNS S32304), super duplex 2507 (UNS S32750), and super duplex Zeron 100 (UNS S32760). Custom grades are available on inquiry.
What is the ASME code for duplex stainless steel pipes?
The ASME code for duplex stainless steel pipes is ASME SA790 (welded and seamless pipe) and ASME SA789 (welded and seamless tube). Duplex 2205 pipe and tube are specified under these codes for general corrosive applications with excellent resistance to stress corrosion cracking.
What is the difference between duplex and super duplex stainless steel pipe?
Standard duplex (2205) contains approximately 22 percent chromium and has a PREN of 34 to 38. Super duplex (2507) contains 25 percent chromium with higher molybdenum and nitrogen, delivering a PREN above 40. Super duplex offers superior resistance to pitting and crevice corrosion in more aggressive environments such as deep sea seawater and concentrated chloride solutions.
Can duplex steel pipes be welded?
Yes, duplex stainless steel pipes can be welded using TIG, MIG, or plasma welding processes. Filler metals matching or closely matching the base metal chemistry are recommended. Post-weld heat treatment (solution annealing) may be required to restore the correct phase balance and corrosion resistance. Amardeep Steel supplies duplex pipe with welding procedure specifications (WPS) available on request.
What industries use duplex stainless steel pipe?
Duplex stainless steel pipe is widely used in offshore oil and gas, onshore pipelines, chemical and petrochemical processing, desalination and water treatment, marine and shipbuilding, pulp and paper mills, heat exchangers, pharmaceutical manufacturing, and food processing industries.
Duplex Steel Pipe Exporter and Global Supply
Amardeep Steel exports duplex stainless steel pipes and tubes to more than 80 countries. Our global clients include EPC contractors, oil majors, shipyards, chemical plants, desalination operators, and industrial distributors. We ship from our Mumbai warehouse with documentation for any port of discharge.
Key export markets include the United Arab Emirates, Saudi Arabia, Qatar, Kuwait, Oman, the United States, the United Kingdom, Germany, Italy, Australia, Singapore, South Korea, Japan, Malaysia, South Africa, and Brazil. Contact us for freight-on-board or cost-insurance-freight quotations to any destination.
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