Duplex Steel Welded Tubes Manufacturer in India
Duplex Steel Welded Tubes Manufacturer in India
Sachiya Steel International is a leading Duplex Steel Welded Tubes Manufacturer in India with experience in pipes and tubes since 2005. Not every duplex tube application requires seamless construction. For condensers, coolers, heat exchangers and process lines operating at suitable pressure levels, welded duplex tubes can offer reliable corrosion resistance, consistent wall thickness and a practical cost advantage. We supply tubes in different duplex grades, sizes and specifications, with popular sizes available from ready stock subject to availability.
Our quality systems include ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018, along with PED 2014/68/EU and TUV approvals. Every order includes an EN 10204 3.1 certificate, while 3.2 certification and third-party inspection are available on request. For customers comparing Duplex Steel Welded Tubes Suppliers, we support requirements covering grade, outside diameter, wall thickness, finish, heat treatment and documentation. As a Duplex Steel Welded Tubes Supplier in India, we also handle international shipments and supply to 85+ countries.
What Are Duplex Steel Welded Tubes?
Duplex Steel Welded Tubes are stainless steel tubes made by rolling duplex strip into a round section and joining the edges with a longitudinal weld. Duplex steel holds about equal parts austenite and ferrite. This mix gives high strength and strong resistance to chloride pitting and stress corrosion cracking.
Under ASTM A789, welded duplex tubes are made by an automatic welding process with no filler metal added. The tube is then solution annealed, so the weld and the parent metal share the same balanced structure. When done right, the seam resists corrosion as well as the rest of the tube. A tube is sized by outside diameter and wall, so you order it in millimetres, not by pipe schedule.
Duplex Steel Welded Tubes
High-quality duplex steel welded tubes manufactured for demanding applications across chemical, petrochemical, power generation, marine, construction and engineering industries. Available in multiple sizes, wall thicknesses, grades and manufacturing specifications, with required testing, inspection and material certificates.
Types of Duplex Steel Welded Tubes
We offer different types of Duplex Steel Welded Tubes based on grade, manufacturing condition, surface finish and tube shape. Our range includes:
- Lean Duplex Welded Tubes: S32101 and S32304 grades for moderate corrosion service and general industrial applications.
- Standard Duplex Welded Tubes: S31803 and S32205 grades from the Duplex 2205 family for heat exchangers, process equipment, chemical plants and marine systems.
- Super Duplex Welded Tubes: S32750 and S32760 grades for severe chloride environments, seawater systems, offshore equipment and demanding process applications.
- Solution Annealed Welded Tubes: Supplied after solution heat treatment to achieve the required metallurgical condition and mechanical properties.
- Cold-Drawn Welded Tubes: Further processed after welding for closer control of outside diameter, wall thickness and surface finish.
- Pickled and Passivated Welded Tubes: Supplied with a clean surface after treatment to remove scale and surface contamination.
- Bright Annealed Welded Tubes: Finished with a smooth, bright surface for selected process and instrumentation applications.
- Straight Welded Tubes: Available in specified lengths for heat exchanger bundles, process lines and tube assemblies.
- U-Bend Welded Tubes: Manufactured in U-shaped configurations for U-tube heat exchangers according to required dimensions.
As a Duplex Steel Welded Tubes Manufacturer, we can supply these types according to the required grade, dimensions, finish and application.
S31803, S32205, S32750, S32760 and S32304 Duplex Steel Welded Tubes Manufacturers and Suppliers in India
We manufacture and supply Duplex Steel Welded Tubes in commonly required grades including UNS S31803, S32205, S32750, S32760 and S32304. Each grade offers different levels of strength and corrosion resistance, making it suitable for specific industrial services.
- UNS S31803 Duplex Steel Welded Tubes: Duplex 2205 grade with good strength and corrosion resistance. Suitable for chemical processing, marine equipment, process piping and general industrial service.
- UNS S32205 Duplex Steel Welded Tubes: Duplex 2205 grade with controlled chemistry and strong resistance to general and chloride corrosion. Used in oil and gas, petrochemical, heat exchanger and process applications.
- UNS S32750 Duplex Steel Welded Tubes: Super Duplex 2507 grade offering high strength and excellent chloride corrosion resistance. Suitable for seawater, desalination, offshore and chemical processing applications.
- UNS S32760 Duplex Steel Welded Tubes: Super Duplex grade with strong resistance to pitting and crevice corrosion. Used in seawater systems, marine equipment, oil and gas and aggressive chemical environments.
- UNS S32304 Duplex Steel Welded Tubes: Lean Duplex 2304 grade offering good mechanical strength and corrosion resistance. Suitable for 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.
Pipes and Tubes
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Seamless Pipes
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ERW Pipes
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LSAW Pipes
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SSAW Pipes
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Seamless Tubes
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Welded Pipes
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Welded Tubes
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Box Pipes
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Box Tubes
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Brass Pipes
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Heat Exchanger Tubes
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Boiler Tubes
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Aluminium Pipes
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Carbon Steel Seamless Pipes
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Carbon Steel Pipe
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Stainless Steel Pipe
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Alloy Steel Pipe
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Duplex Steel Pipe
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Super Duplex Steel Pipe
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Nickel Alloy Pipe
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Copper Nickel Alloy Pipe
→Get Certified Duplex Steel Welded Tubes at Competitive Factory Prices
Duplex Steel Welded Tubes Specification
The table below sets out the working specification.
| Item | Detail |
|---|---|
| Product | Duplex Steel Welded Tubes |
| Process | Formed from strip, longitudinal automatic weld without filler metal, solution annealed |
| Grades | S31803, S32205, S32750, S32760, S32304, S32101 |
| Tube standards | ASTM A789 / ASME SA789, EN 10217-7 |
| General requirements | ASTM A1016 |
| Size basis | OD and wall thickness in mm |
| Size reference | OD 12.7 to 101.6 mm in the weight chart, other sizes on request |
| Length | Random, fixed or cut length |
| Shapes | Straight tubes, or U-bend against a drawing |
| Finish | Pickled and passivated, bright annealed or cold drawn |
| Heat treatment | Solution annealed and quenched |
| 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 Welded Tubes Standards and Specifications
Welded duplex tubes are bought to a tube standard, a general requirements standard and, for harsh service, a corrosion or sour-service standard. The table sets out 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 10217-7 | Welded stainless steel tubes for pressure purposes | EN-code projects |
| 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 |
| ASME B31.3 | Process piping design code | Weld joint factors, applied by your engineer |
| EN 10204 | Types of inspection documents | 3.1 and 3.2 certificates |
Duplex Steel Welded 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+ | Condensers, heat exchangers |
| S32205 | S32205 | 1.4462 | Duplex 2205 | 35 | Condensers, higher spec than S31803 |
| S32750 | S32750 | 1.4410 | Super duplex 2507 | 40+ | Hot seawater and brine duty |
| S32760 | S32760 | 1.4501 | Super duplex | 40+ | Aggressive chloride duty |
What Is the Difference Between Duplex Steel Welded Tubes and Duplex Steel Seamless Tubes?
The short answer: welded tubes are rolled from strip and have one weld seam, while seamless tubes are pierced from a billet and have none. Welded duplex tubes cost less and have a very even wall. Seamless tubes suit the highest pressures and the heaviest walls.
| If you need | Better pick | Reason |
|---|---|---|
| Lowest cost per metre | Welded | Strip is cheaper than billet |
| A very even wall | Welded | Strip has uniform thickness |
| Fast delivery of common sizes | Welded | Shorter production route |
| Highest pressure or heavy wall | Seamless | No seam, thicker walls available |
| Design with no weld joint factor | Seamless | Codes apply a factor to welded tube |
| Moderate pressure, chloride duty | Welded | Strength is the same after solution annealing |
| Very small bore tubing | Seamless | Easier to draw to small sizes |
Duplex Steel Welded Tubes Chemical Composition
Chemistry sets the phase balance and corrosion resistance. The first table shows the main alloying elements under ASTM A789. Values are percentage by weight, maximum unless shown as a range.
| Grade | Cr | Ni | Mo | N | Mn | Cu | W |
|---|---|---|---|---|---|---|---|
| S32101 | 21.0–22.0 | 1.35–1.70 | 0.10–0.80 | 0.20–0.25 | 4.00–6.00 | 0.10–0.80 | — |
| S32304 | 21.5–24.5 | 3.0–5.5 | 0.05–0.60 | 0.05–0.20 | 2.50 max | 0.05–0.60 | — |
| S31803 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | 2.00 max | — | — |
| S32205 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | 2.00 max | — | — |
| S32750 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 | 1.20 max | 0.50 max | — |
| S32760 | 24.0–26.0 | 6.0–8.0 | 3.0–4.0 | 0.20–0.30 | 1.00 max | 0.50–1.00 | 0.50–1.00 |
Carbon, Silicon and Residual Elements
| Grade | C max | Si max | P max | S max |
|---|---|---|---|---|
| S32101 | 0.040 | 1.00 | 0.040 | 0.030 |
| S32304 | 0.030 | 1.00 | 0.040 | 0.040 |
| S31803 | 0.030 | 1.00 | 0.030 | 0.020 |
| S32205 | 0.030 | 1.00 | 0.030 | 0.020 |
| S32750 | 0.030 | 0.80 | 0.035 | 0.020 |
| S32760 | 0.030 | 1.00 | 0.030 | 0.010 |
Duplex Steel Welded Tubes Mechanical Properties
Mechanical properties show the strength of the tube after solution annealing. The table gives minimum values, in MPa with ksi in brackets.
| Grade | Yield min, MPa (ksi) | Tensile min, MPa (ksi) | Elongation min (%) | Hardness max |
|---|---|---|---|---|
| S32101 | 450 (65) | 650 (94) | 30 | 290 HBW |
| S32304 | 400 (58) | 600 (87) | 25 | 290 HBW |
| S31803 | 450 (65) | 620 (90) | 25 | 290 HBW |
| S32205 | 450 (65) | 655 (95) | 25 | 290 HBW |
| S32750 | 550 (80) | 800 (116) | 15 | 310 HBW |
| S32760 | 550 (80) | 750 (109) | 25 | — |
Duplex Steel Welded 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 38.1 mm OD tube with a 2.11 mm wall (14 BWG) weighs (38.1 − 2.11) × 2.11 × 0.02450 = 1.86 kg/m. All figures below are in kg/m.
| Wall (BWG, mm) | 12.7 OD | 19.05 OD | 25.4 OD | 38.1 OD | 50.8 OD | 76.2 OD | 101.6 OD |
|---|---|---|---|---|---|---|---|
| 18 BWG, 1.24 | 0.35 | 0.54 | 0.73 | 1.12 | 1.51 | 2.28 | 3.05 |
| 16 BWG, 1.65 | 0.45 | 0.70 | 0.96 | 1.47 | 1.99 | 3.01 | 4.04 |
| 14 BWG, 2.11 | 0.55 | 0.88 | 1.20 | 1.86 | 2.52 | 3.83 | 5.14 |
| 12 BWG, 2.77 | 0.67 | 1.10 | 1.54 | 2.40 | 3.26 | 4.98 | 6.71 |
| 10 BWG, 3.40 | 0.77 | 1.30 | 1.83 | 2.89 | 3.95 | 6.06 | 8.18 |
Available Sizes, Dimensions and Tolerances
Duplex Steel Welded Tubes are ordered by OD, wall and length. The chart above covers OD 12.7 to 101.6 mm, and other sizes can be quoted on request. Tolerances follow ASTM A1016. For welded tubes ordered by nominal wall, the wall may vary by ±10%. The table shows typical OD limits for cold-finished tubes.
| OD (mm) | OD tolerance (±mm) |
|---|---|
| 12.7 | 0.10 |
| 19.05 | 0.10 |
| 25.4 | 0.15 |
| 38.1 | 0.15 |
| 50.8 | 0.25 |
| 63.5 | 0.30 |
| 76.2 | 0.38 |
| 101.6 | 0.38 |
Tell us the OD and wall tolerance your tubesheet or fitting needs, and we will quote against it.
Common Materials in Duplex Steel Welded Tubes
We manufacture and supply commonly requested materials in Duplex Steel Welded Tubes for heat exchangers, condensers, process equipment, marine systems and other industrial applications. Our range includes:
UNS S31803 / S32205 (1.4462): Duplex 2205 grades with around 22% chromium and 3% molybdenum, suitable for condensers, heat exchangers and process applications.
UNS S32750 (1.4410): Super Duplex 2507 grade with around 25% chromium and 4% molybdenum, used for hot seawater, desalination, offshore and demanding sour-service applications.
UNS S32760 (1.4501): Super Duplex grade containing chromium, molybdenum, tungsten and copper, suitable for aggressive chloride environments and seawater applications.
UNS S32304 (1.4362): Lean Duplex 2304 grade offering good strength and corrosion resistance for moderate-duty applications.
UNS S32101 (1.4162): Lean Duplex 2101 grade with low nickel content and additions of manganese and nitrogen, used for applications requiring good strength and corrosion resistance.
As experienced Duplex Steel Welded Tubes Suppliers, we can supply these grades in different tube sizes, wall thicknesses, finishes and specifications according to the required application.
Duplex Steel Welded Tubes We Manufacture and Supply
We make Duplex Steel Welded 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 |
| Process and utility tubing | S32205, S32304 | Straight, bright annealed |
| Lean-duty coolers and tanks | S32101, S32304 | Straight |
Applications of Duplex Steel Welded Tubes
- Condensers: Seawater-cooled condensers in power stations and on ships.
- Heat exchangers: Shell and tube bundles in refineries and chemical plants.
- Desalination plants: Brine heaters and seawater coolers.
- Oil and gas: Produced-water coolers and process tubing.
- Offshore and marine: Firewater, ballast and cooling water lines.
- Chemical and petrochemical plants: Coolers carrying chloride or acid fluids.
- Pulp and paper mills: Liquor heaters and bleach plant tubing.
- Pharmaceutical plants: Utility heat exchangers outside the product-contact zone.
Why Choose Us as Your Duplex Steel Welded Tubes Manufacturer in India?
We have been manufacturing and supplying pipes and tubes since 2005, giving us more than two decades of practical experience with duplex steel products. Over the years, we have handled different grades, tube sizes, wall thicknesses, finishes and specifications for industrial requirements. We manufacture UNS S31803, S32205, S32750, S32760 and S32304 Duplex Steel Welded Tubes in different dimensions, with popular sizes available from ready stock, subject to availability. Our supply capability can reach 100 tons per month, depending on grade, size and order requirements. This experience makes us a dependable Duplex Steel Welded Tubes Supplier in India.
We maintain proper documentation with EN 10204 3.1 certification supplied with every order, while 3.2 certification and third-party inspection are available on request. Our quality credentials include ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018, along with PED 2014/68/EU and TUV approvals. We also handle export packing, documentation and shipment requirements, with our duplex steel welded tubes supplied to 85+ countries. Our long experience in manufacturing and international supply helps us manage duplex tube orders with the required grade, dimensions, certificates and delivery arrangements.
Countries We Export Duplex Steel Welded Tubes To
Duplex Steel Welded Tubes are supplied from India to 85+ countries, covering established industrial markets in the Middle East, Europe, Asia-Pacific, the Americas and Africa. Our international supply includes standard and project-specific tube requirements, with the grade, dimensions and order specifications considered before dispatch.
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
For overseas orders, we arrange the applicable material and shipment documentation along with the required packing. EN 10204 3.1 certification is supplied with every order, while EN 10204 3.2 and third-party inspection can be provided when requested. This export setup supports duplex welded tube shipments for industrial requirements in different international markets.
Duplex Steel Welded Tubes FAQs
Common questions about duplex welded tube grades, weld seams, seawater service, U-bends, and supply.
Which duplex grade should I pick for a seawater condenser?
S32205 works for many condensers. For warm, polluted or stagnant seawater, step up to super duplex S32750 or S32760.
Is the weld seam as corrosion resistant as the tube?
Yes, when the tube is welded correctly and solution annealed after welding. The anneal restores the balance of austenite and ferrite across the seam.
Is filler metal used when welding the tube?
For ASTM A789 welded tube, no filler metal is added during welding. The seam is made by an automatic process, then heat treated.
When should I choose welded tubes over seamless tubes?
Choose welded tube when cost, wall evenness and delivery time matter and the pressure is moderate. Choose seamless for the highest pressure or the heaviest wall.
Is the seam tested?
Yes. ASTM A789 requires a hydrostatic test or a non-destructive electric test on each tube, plus flattening and flaring tests on samples. Tell us your preferred test when you enquire.
Can welded duplex tubes be used in sour service?
Yes, within the limits of NACE MR0175 / ISO 15156, which set hardness, temperature and H2S limits. State the sour-service requirement when you enquire.
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 code.
What tolerances apply to OD and wall?
ASTM A1016 sets them. The table above gives typical OD limits for cold-finished tubes, and wall varies by ±10% when ordered by nominal wall.
What sizes can I order?
The chart above covers OD 12.7 to 101.6 mm in walls from 1.24 to 3.40 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 Welded Tubes?
Grade is the main factor, because nickel, molybdenum and nitrogen content move the cost. OD, wall, finish, length, 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.
Are you a manufacturer or a supplier of Duplex Steel Welded 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 Welded 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.