Duplex Steel Seamless Tubes Manufacturer in India
Duplex Steel Seamless Tubes Manufacturer in India
Sachiya Steel International is a leading Duplex Steel Seamless Tubes Manufacturer in India, supplying seamless tubes for applications that require high strength and good resistance to corrosion. We have been manufacturing and supplying pipes and tubes in India since 2005, with a facility near Mumbai and an export office in Mumbai. Our duplex steel seamless tubes are available in different grades, outside diameters, wall thicknesses and specifications for industrial requirements. Popular sizes can be supplied from ready stock, subject to availability.
Our duplex steel seamless tubes are used in chemical processing, oil and gas, petrochemical, marine, desalination, heat exchanger and power applications. We provide EN 10204 3.1 certification with every order, while 3.2 certification and third-party inspection are available on request. Our certifications include ISO 9001:2015, ISO 14001:2015, ISO 45001:2018, PED 2014/68/EU and TUV approvals. We supply customers in India and export to 85+ countries, with packing and shipping documentation arranged according to the requirements of each order.
What Are Duplex Steel Seamless Tubes?
Duplex Steel Seamless Tubes are tubes made from duplex stainless steel and manufactured without a longitudinal welded seam. They have a two-phase structure of austenite and ferrite, which gives them a combination of high strength, toughness, and corrosion resistance.
These tubes are commonly supplied in grades such as UNS S31803, S32205, S32750, S32760 and S32304. Duplex Steel Seamless Tubes are used in heat exchangers, chemical processing equipment, oil and gas systems, marine equipment, desalination plants and other applications where strength and resistance to corrosion are important.
Duplex Steel Seamless Tubes
High-quality Duplex Steel Seamless Tubes manufactured for demanding applications across chemical, petrochemical, oil & gas, power generation, marine, construction and engineering industries. Available in UNS S31803 and S32205 grades, multiple sizes, wall thicknesses and ASTM A789 / ASME specifications.
Types of Duplex Steel Seamless Tubes
Different duplex seamless tube types are selected according to grade, finish, dimensions and application. A Duplex Steel Seamless Tubes Manufacturer can supply the following commonly used types:
- Duplex 2205 Seamless Tubes: UNS S31803 and S32205 grades offering good strength and corrosion resistance for process, chemical and marine applications.
- Super Duplex 2507 Seamless Tubes: UNS S32750 grade designed for severe chloride environments, seawater systems and offshore applications.
- Super Duplex S32760 Seamless Tubes: High-strength duplex tubes with strong resistance to pitting, crevice corrosion and aggressive process environments.
- Lean Duplex 2304 Seamless Tubes: UNS S32304 grade for moderate corrosion service where good strength and corrosion resistance are required.
- Lean Duplex 2101 Seamless Tubes: UNS S32101 grade with lower nickel content and good mechanical strength for selected industrial applications.
- Cold Finished Seamless Tubes: Produced with closer dimensional control and a smoother surface where the application requires tighter tube dimensions.
- Hot Finished Seamless Tubes: Suitable for industrial applications requiring larger dimensions and robust tube construction.
- Heat Exchanger Seamless Tubes: Supplied for heat-transfer equipment, condensers and process systems where duplex stainless steel provides corrosion resistance.
S31803, S32205, S32750, S32760 and S32304 Duplex Steel Seamless Tubes Manufacturers and Suppliers in India
Duplex Steel Seamless Tubes are available in different grades to meet requirements for strength, corrosion resistance and demanding service conditions. We manufacture and supply UNS S31803, S32205, S32750, S32760 and S32304 grades for heat exchangers, chemical processing, oil and gas, marine and other industrial applications.
- UNS S31803 Duplex Steel Seamless Tubes: Duplex 2205 grade with good strength and corrosion resistance for chemical processing, marine and process applications.
- UNS S32205 Duplex Steel Seamless Tubes: Duplex 2205 grade with controlled chemistry and good resistance to general and chloride corrosion. Suitable for oil and gas, petrochemical and process equipment.
- UNS S32750 Duplex Steel Seamless Tubes: Super Duplex 2507 grade offering high strength and excellent resistance to chloride-containing environments. Used in desalination, seawater, offshore and chemical applications.
- UNS S32760 Duplex Steel Seamless Tubes: Super Duplex grade with strong resistance to pitting and crevice corrosion. Suitable for aggressive marine, seawater, oil and gas and chemical-processing environments.
- UNS S32304 Duplex Steel Seamless Tubes: Lean Duplex 2304 grade offering good mechanical strength and corrosion resistance. Used in moderate-duty process equipment and general corrosion-resistant applications.
Types of Pipes & Tubes
Explore our range of industrial pipes and tubes, manufactured for different applications, materials, specifications and engineering requirements.
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Carbon Steel Pipe
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Copper Nickel Alloy Pipe
→Get Certified Duplex Steel Seamless Tubes at Competitive Factory Prices
Duplex Steel Seamless Tubes Specification
The table sets out the working specification.
| Item | Detail |
|---|---|
| Product | Duplex Steel Seamless Tubes |
| Process | Seamless, hot finished or cold drawn |
| Grades | S31803, S32205, S32750, S32760, S32304, S32101 |
| Tube standards | ASTM A789 / ASME SA789, EN 10216-5 |
| General requirements | ASTM A1016 |
| Size basis | OD and wall thickness in mm, wall by minimum or average |
| Size reference | OD 6.35 to 50.8 mm in the weight chart, other sizes on request |
| Length | Random, fixed or cut length |
| Shapes | Straight tubes, or U-bend against a drawing |
| Heat treatment | Solution annealed and quenched |
| Surface | Pickled and passivated, or bright annealed |
| Tests | Chemical analysis, tensile, hardness, flattening, flaring, hydrostatic or eddy current test, ASTM A923 on request |
| Certificate | EN 10204 3.1 with every order, 3.2 on request |
| Inspection | Third-party inspection on request |
Duplex Steel Seamless Tubes Standards and Specifications
Duplex tubes are bought to a tube standard, a general requirements standard and, for demanding service, a corrosion or sour-service standard. The table lists each.
| Standard | Scope | Where it applies |
|---|---|---|
| ASTM A789 / ASME SA789 | Seamless and welded ferritic/austenitic stainless tubing for general service | Main duplex tube standard |
| ASTM A1016 | General requirements for ferritic alloy, austenitic and duplex tubes | Tolerances, tests, marking |
| EN 10216-5 | Seamless stainless steel tubes for pressure purposes | EN-code projects |
| ASTM A790 | Seamless and welded duplex pipe | Companion pipe standard |
| ASTM A923 | Test methods for detrimental intermetallic phases | Structure check |
| ASTM G48 | Pitting and crevice corrosion test | Corrosion check |
| NACE MR0175 / ISO 15156 | Materials for sour service | Oil and gas projects |
| TEMA | Standards for shell and tube heat exchangers | Tube sizes and fits |
| EN 10204 | Types of inspection documents | 3.1 and 3.2 certificates |
Duplex Steel Seamless Tubes Material and Grades
Choose the grade by chloride level, temperature and cost. PREN, the pitting resistance equivalent number, is a rough pitting index: Cr + 3.3 × Mo + 16 × N. A higher number means better resistance.
| Grade | UNS | EN number | Name | PREN (about) | Typical tube use |
|---|---|---|---|---|---|
| S32101 | S32101 | 1.4162 | Lean duplex 2101 | 26 | Tanks, mild-duty exchangers |
| S32304 | S32304 | 1.4362 | Lean duplex 2304 | 25 | Water and process coolers |
| S31803 | S31803 | 1.4462 | Duplex 2205 | 34+ | Heat exchangers, condensers |
| S32205 | S32205 | 1.4462 | Duplex 2205 | 35 | Heat exchangers, higher spec than S31803 |
| S32750 | S32750 | 1.4410 | Super duplex 2507 | 40+ | Hot seawater, brine, subsea lines |
| S32760 | S32760 | 1.4501 | Super duplex | 40+ | Seawater coolers, aggressive chloride duty |
What Is the Difference Between Duplex Steel Seamless Tubes and Stainless Steel Seamless Tubes?
The short answer: duplex tubes have about two to three times the yield strength of 304 and 316L tubes and resist chloride stress corrosion cracking far better. Standard stainless tubes are cheaper per tonne and easier to form, so they remain the choice for mild duty. In a heat exchanger, a stronger duplex tube can use a thinner wall, which improves heat transfer.
| Point | Duplex Steel Seamless Tubes | Stainless Steel Seamless Tubes (304, 316L) | Why it matters |
|---|---|---|---|
| Structure | Austenite and ferrite | Austenite | Sets strength and cracking resistance |
| Yield strength | 400 to 550 MPa and above | About 170 to 205 MPa | Thinner wall for the same pressure |
| Chloride stress corrosion | High resistance | Low resistance | Long life in seawater and brine |
| Pitting resistance | Medium to very high | Medium | Fewer leaks in chloride duty |
| Thermal expansion | Lower | Higher | Less stress at the tubesheet |
| Temperature limit | Keep below about 300°C | Higher | Check against service temperature |
| Cost per tonne | Higher | Lower | Less steel needed in duplex |
| Typical use | Condensers, subsea lines, desalination | General process, food, water | Pick by duty |
Duplex Steel Seamless Tubes Chemical Composition
Chemistry sets the phase balance and the corrosion resistance. Nitrogen raises strength and pitting resistance. The first table covers the lean and standard grades under ASTM A789. Values are percentage by weight, maximum unless shown as a range.
| Grade | C | Mn | Si | P | S | Cr | Ni | Mo | N | Cu |
|---|---|---|---|---|---|---|---|---|---|---|
| S32101 | 0.040 | 4.00–6.00 | 1.00 | 0.040 | 0.030 | 21.0–22.0 | 1.35–1.70 | 0.10–0.80 | 0.20–0.25 | 0.10–0.80 |
| S32304 | 0.030 | 2.50 | 1.00 | 0.040 | 0.040 | 21.5–24.5 | 3.0–5.5 | 0.05–0.60 | 0.05–0.20 | 0.05–0.60 |
| S31803 | 0.030 | 2.00 | 1.00 | 0.030 | 0.020 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | — |
| S32205 | 0.030 | 2.00 | 1.00 | 0.030 | 0.020 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | — |
Super Duplex Grades
| Element | S32750 | S32760 |
|---|---|---|
| Carbon (C) max | 0.030 | 0.030 |
| Manganese (Mn) max | 1.20 | 1.00 |
| Silicon (Si) max | 0.80 | 1.00 |
| Phosphorus (P) max | 0.035 | 0.030 |
| Sulphur (S) max | 0.020 | 0.010 |
| Chromium (Cr) | 24.0–26.0 | 24.0–26.0 |
| Nickel (Ni) | 6.0–8.0 | 6.0–8.0 |
| Molybdenum (Mo) | 3.0–5.0 | 3.0–4.0 |
| Nitrogen (N) | 0.24–0.32 | 0.20–0.30 |
| Copper (Cu) | 0.50 max | 0.50–1.00 |
| Tungsten (W) | — | 0.50–1.00 |
Duplex Steel Seamless Tubes Mechanical Properties
Mechanical properties show the strength gain over standard stainless. The table gives minimum values and compares yield strength with 316L, which has a minimum yield of 170 MPa.
| Grade | Yield min (MPa) | Tensile min (MPa) | Elongation min (%) | Hardness max | Yield vs 316L (about) |
|---|---|---|---|---|---|
| S32101 | 450 | 650 | 30 | 290 HBW | 2.6 times |
| S32304 | 400 | 600 | 25 | 290 HBW | 2.4 times |
| S31803 | 450 | 620 | 25 | 290 HBW | 2.6 times |
| S32205 | 450 | 655 | 25 | 290 HBW | 2.6 times |
| S32750 | 550 | 800 | 15 | 310 HBW | 3.2 times |
| S32760 | 550 | 750 | 25 | — | 3.2 times |
Duplex Steel Seamless Tubes Size and Weight Chart
Weight depends on OD and wall thickness. Duplex steel has a density of about 7.80 g/cm³, so we use this formula:
OD and wall are in mm. Example: a 25.4 mm OD tube with a 2.0 mm wall weighs (25.4 − 2.0) × 2.0 × 0.02450 = 1.15 kg/m. A dash means the wall is too thick for that OD.
| OD (mm) | 1.0 mm wall (kg/m) | 1.5 mm wall (kg/m) | 2.0 mm wall (kg/m) | 3.0 mm wall (kg/m) |
|---|---|---|---|---|
| 6.35 | 0.13 | 0.18 | 0.21 | — |
| 9.53 | 0.21 | 0.30 | 0.37 | 0.48 |
| 12.7 | 0.29 | 0.41 | 0.52 | 0.71 |
| 19.05 | 0.44 | 0.64 | 0.84 | 1.18 |
| 25.4 | 0.60 | 0.88 | 1.15 | 1.65 |
| 31.75 | 0.75 | 1.11 | 1.46 | 2.11 |
| 38.1 | 0.91 | 1.35 | 1.77 | 2.58 |
| 50.8 | 1.22 | 1.81 | 2.39 | 3.51 |
Available Sizes, Dimensions and Tolerances
Duplex Steel Seamless Tubes are ordered by OD, wall and length. The chart above covers OD 6.35 to 50.8 mm, and other sizes can be quoted on request. Tolerances follow ASTM A1016 and depend on the OD. The table shows typical limits for cold-finished tubes ordered by minimum wall.
| OD (mm) | OD tolerance (mm) | Wall tolerance, minimum wall |
|---|---|---|
| Under 25.4 | ±0.10 | +20% / −0 |
| 25.4 to 38.1 | ±0.15 | +20% / −0 |
| Over 38.1 to under 50.8 | ±0.20 | +22% / −0 |
| 50.8 to under 63.5 | ±0.25 | +22% / −0 |
Hot-finished tubes carry wider limits. Tell us the OD and wall tolerance your tubesheet or fitting needs, and we will quote against it.
Common Materials in Duplex Steel Seamless Tubes
These are the materials commonly requested from Duplex Steel Seamless Tubes Suppliers for heat exchangers, condensers, chemical processing, marine systems and other corrosion-resistant applications.
UNS S31803 and S32205 (1.4462): Duplex 2205 grades with around 22% chromium and 3% molybdenum. Commonly selected for heat exchangers, condensers, process equipment and general corrosion-resistant service.
UNS S32750 (1.4410): Super Duplex 2507 with around 25% chromium and 4% molybdenum. Suitable for hot seawater, offshore systems, desalination and demanding sour-service environments.
UNS S32760 (1.4501): Super Duplex grade containing chromium, molybdenum, tungsten and copper. Used for aggressive chloride environments, seawater systems and demanding industrial service.
UNS S32304 (1.4362): Lean Duplex 2304 with good strength and corrosion resistance. Suitable for moderate-duty applications where a lean duplex material is appropriate.
UNS S32101 (1.4162): Lean Duplex 2101 with low nickel content and additions of manganese and nitrogen. Used where good strength and corrosion resistance are required for selected industrial applications.
Duplex Steel Seamless Tubes We Manufacture and Supply
We make Duplex Steel Seamless Tubes for the jobs below. The grade follows the fluid and the temperature.
| Service | Grades | Tube form |
|---|---|---|
| Seawater-cooled condensers | S32205, S32750 | Straight, cold drawn |
| Shell and tube heat exchangers | S31803, S32205, S32304 | Straight or U-bend |
| Desalination exchangers | S32205, S32750, S32760 | Straight, cold drawn |
| Subsea and offshore tubing | S32750, S32760 | Straight, cold drawn or bright annealed |
| Lean-duty coolers and tanks | S32101, S32304 | Straight |
Applications of Duplex Steel Seamless Tubes
- Heat exchangers and coolers: Shell and tube bundles in refineries and chemical plants.
- Condensers: Seawater-cooled condensers in power stations and on ships.
- Desalination plants: Brine heaters and high-pressure seawater tubes.
- Oil and gas: Produced-water coolers, hydraulic and chemical injection lines.
- Offshore and marine: Firewater, ballast and cooling water tubes.
- Chemical and petrochemical plants: Reactors and coolers carrying chloride or acid fluids.
- Pulp and paper mills: Digester and liquor heaters.
- Pharmaceutical plants: Utility heat exchangers and water systems outside the product-contact zone.
Why Choose Us as Your Duplex Steel Seamless Tubes Manufacturer in India?
We have been manufacturing and supplying pipes and tubes since 2005, giving us over two decades of experience in handling duplex steel tube requirements. Over the years, we have developed practical knowledge of different duplex grades, tube dimensions, wall thicknesses, finishes and specifications. We manufacture UNS S31803, S32205, S32750, S32760 and S32304 Duplex Steel Seamless Tubes in different sizes and lengths. Popular sizes can also be available from ready stock, subject to availability. Our supply capability can reach 100 tons per month, depending on the grade, size and order requirements. This experience makes us a reliable Duplex Steel Seamless Tubes Supplier in India for standard and application-specific requirements.
Our manufacturing and supply process is supported by EN 10204 3.1 certification with every order, while 3.2 certification and third-party inspection are available on request. We hold ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certifications, along with PED 2014/68/EU and TUV approvals. We also have experience in export packing, documentation and shipment handling, with duplex steel seamless tubes supplied to 85+ countries. This combination of long-standing experience, grade knowledge, dimensional control and documentation support helps maintain consistency across domestic and international orders.
Countries We Export Duplex Steel Seamless Tubes To
We export Duplex Steel Seamless Tubes to customers in 85+ countries, with experience in handling international requirements for different grades, tube sizes, wall thicknesses, certificates, packing and shipment documentation. Our export network covers major industrial markets across the Middle East, Europe, Asia-Pacific, the Americas and Africa.
Middle East: UAE, Saudi Arabia, Qatar, Oman, Kuwait and Bahrain
Europe: Germany, Italy, United Kingdom, Netherlands, France, Norway and Spain
Asia-Pacific: Singapore, Malaysia, Indonesia, Thailand, Vietnam and Australia
North and South America: USA, Canada, Mexico and Brazil
Africa: South Africa, Nigeria, Egypt and Kenya
Export orders include EN 10204 3.1 certification with every order, while 3.2 certification and third-party inspection are available on request. We also arrange suitable export packing and documentation according to the shipment requirements. Our experience in international supply helps maintain clear coordination from order processing through dispatch for duplex steel seamless tube shipments.
Duplex Steel Seamless Tubes FAQs
Common questions about duplex seamless tube grades, seawater service, U-bends, testing, and supply.
Which duplex grade should I pick for a seawater condenser?
S32205 works for many seawater condensers. For warm, polluted or stagnant seawater, step up to super duplex S32750 or S32760 for higher pitting resistance.
How do I choose between S32205 and S32750 tubes?
Look at chloride level and temperature. S32205 suits most heat exchanger duty. S32750 is for severe chloride, higher temperatures and sour service, and it costs more.
Why use duplex tubes instead of 316L?
Duplex tubes are far stronger and resist chloride cracking, so they last longer in seawater and brine. The thinner wall they allow can also improve heat transfer.
Should I order tubes by minimum wall or average wall?
Minimum wall guarantees the thinnest point meets your design calculation. Average wall allows a plus-minus variation around nominal. Your exchanger designer should state the basis on the order.
Can the tubes be expanded into a tubesheet or welded to it?
Yes. Duplex tubes are rolled or welded into tubesheets in practice. Use a qualified procedure and a duplex or compatible tubesheet material, and control heat input when welding.
What is the maximum service temperature?
Keep duplex below about 300°C. Long exposure at higher temperatures can make it brittle. Your engineer should check the limit for the grade and the code.
What tolerances apply to OD and wall?
ASTM A1016 sets them. The table above gives typical limits for cold-finished tubes, and hot-finished tubes carry wider limits.
What sizes can I order?
The chart above covers OD 6.35 to 50.8 mm in walls from 1.0 to 3.0 mm. Other sizes and walls can be quoted on request.
How do I calculate the weight of a tube order?
Use Weight (kg/m) = (OD − Wall) × Wall × 0.02450, with OD and wall in mm. Multiply by length and quantity. Real weight varies slightly with wall tolerance.
What affects the price of Duplex Steel Seamless Tubes?
Grade is the main factor, because nickel, molybdenum and nitrogen content move the cost. OD, wall, finish, length, U-bending, testing, inspection, quantity and freight also count.
Which certificates come with the tubes?
Each order carries an EN 10204 3.1 certificate showing chemistry and mechanical results. A 3.2 certificate and third-party inspection are available on request.
Is every tube tested before it ships?
ASTM A789 requires a hydrostatic test or a non-destructive electric test on each tube. Tell us your preferred test when you enquire.
Are you a manufacturer or a supplier of Duplex Steel Seamless Tubes?
We are both. We manufacture near Mumbai and supply ready stock of popular sizes from the same location, subject to availability.
Can you supply U-bend duplex tubes?
Send your drawing with the bend radius and leg length, and we will confirm what can be made and what heat treatment applies. Straight tubes in standard sizes are the quickest to supply.
Do you export Duplex Steel Seamless Tubes, and how are they packed?
Yes. We ship to 85+ countries from our Mumbai export office, and we pack the tubes to suit sea or air freight and your project needs.