Super Duplex Welded Tubes Manufacturer in India
Super Duplex Welded Tubes Manufacturer in India
Sachiya Steel International, established in 2005, is a Super Duplex Welded Tubes Manufacturer in India with experience in manufacturing and supplying industrial pipes and tubes. Our facility near Mumbai handles different grades, tube sizes, wall thicknesses and specifications, while our export office in Mumbai supports international orders. Over the years, we have developed experience in serving requirements from industries such as oil and gas, chemical processing, marine, offshore, desalination and petrochemical.
We supply super duplex welded tubes for projects and industrial requirements across 85+ countries. Our quality systems include ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018, along with PED 2014/68/EU and TUV approvals. An EN 10204 3.1 certificate is provided with every order, while 3.2 certification and third-party inspection are available on request. Our team also manages the documentation, packing and export requirements involved in international tube supply
What Are Super Duplex Welded Tubes?
Super Duplex Welded Tubes are stainless steel tubes made by rolling super duplex strip into a round section and joining the edges with a longitudinal weld. Super duplex means a duplex steel with a PREN of 40 or higher. PREN, the pitting resistance equivalent number, is a rough index of pitting resistance: Cr + 3.3 × Mo + 16 × N.
Under ASTM A789, welded tubes are made by an automatic welding process with no filler metal added. Because no filler is used, the seam has the same chemistry as the strip. The tube is then solution annealed and quenched, so the weld and the parent metal share the same balance of austenite and ferrite. Many tubes are also cold drawn after welding to bring OD and wall to a tight tolerance.
Super Duplex Welded Tubes
High-quality super duplex 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 Super Duplex Welded Tubes
We manufacture and supply Super Duplex Welded Tubes in different grades, production conditions, surface finishes and tube forms for heat exchangers, process systems, marine equipment and other demanding applications.
- S32750 Welded Tubes (2507): Super Duplex grade widely used for seawater, desalination, offshore, chemical and oil and gas applications.
- S32760 Welded Tubes: Tungsten- and copper-containing super duplex grade for aggressive chloride and marine environments.
- S32550 Welded Tubes: Copper-bearing grade suited to selected acid, chloride and chemical process applications.
- Welded and Solution-Annealed Tubes: Heat treated after welding to obtain the required metallurgical condition and mechanical properties.
- Welded and Cold-Drawn Tubes: Further drawn after welding for closer outside-diameter and wall-thickness control.
- Bright-Annealed Tubes: Supplied with a smooth, clean surface for selected instrument, control and process-line applications.
- Pickled and Passivated Tubes: Surface treated to remove scale and improve surface cleanliness for corrosion-resistant service.
- Straight Tubes: Cut to specified lengths for exchanger bundles, process lines and general tube assemblies.
- U-Bend Tubes: Formed into U shapes according to drawings for U-tube heat exchangers.
Our experience as a Super Duplex Welded Tubes Manufacturer allows us to supply these tube forms in the required grade, dimensions and finish.
S32750, S32760 and S32550 Super Duplex Welded Tubes Manufacturers and Suppliers in India
We manufacture and supply Super Duplex Welded Tubes in UNS S32750, UNS S32760 and UNS S32550 for applications where tube performance must withstand high chloride exposure, seawater and corrosive process conditions.
- UNS S32750 (1.4410): Super Duplex 2507 grade used for heat exchangers, desalination equipment, offshore systems, seawater handling and oil and gas service. It offers high strength together with strong resistance to pitting and crevice corrosion.
- UNS S32760 (1.4501): A tungsten- and copper-containing super duplex grade suited to aggressive chloride environments. It is used in marine, offshore, chemical processing and other demanding applications.
- UNS S32550 (1.4507): Copper-bearing super duplex grade selected for applications involving acidic and chloride-containing media. It combines good mechanical strength with useful corrosion resistance for selected process and marine services.
We supply these grades in different tube outside diameters, wall thicknesses, lengths and finishes. The tube construction and dimensions can be selected according to the application, required specification and fabrication needs
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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Copper Nickel Alloy Pipe
→Get Certified Super Dyplex Welded Tubes at Competitive Factory Prices
Super Duplex Welded Tubes Specification
The table sets out the working specification.
| Item | Detail |
|---|---|
| Product | Super Duplex Welded Tubes |
| Process | Formed from strip, longitudinal automatic weld without filler metal, solution annealed |
| Grades | S32750, S32760, S32550 |
| Tube standards | ASTM A789 / ASME SA789, EN 10217-7 |
| General requirements | ASTM A1016 |
| Size basis | OD and wall thickness in mm |
| Size reference | OD 19.05 to 76.2 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 and G48 on request |
| Certificate | EN 10204 3.1 with every order, 3.2 on request |
| Inspection | Third-party inspection on request |
Super Duplex Welded Tubes Standards and Specifications
Welded super duplex tubes are bought to a tube standard, a general requirements standard and test methods for structure and corrosion. The table lists each.
| Standard | Scope | Where it applies |
|---|---|---|
| ASTM A789 / ASME SA789 | Seamless and welded ferritic/austenitic stainless tubing for general service | Core 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 | Method A, B or C 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 |
Super Duplex Welded Tubes Material and Grades
Pick the grade by the fluid, the chloride level and the temperature. The table lists the grades and their use.
| Grade | UNS | EN number | Name | PREN (about) | Typical tube use |
|---|---|---|---|---|---|
| S32750 | S32750 | 1.4410 | Super duplex 2507 | 42 | Hot-seawater coolers, injection lines |
| S32760 | S32760 | 1.4501 | Super duplex | 41 | Offshore coolers, aggressive chloride duty |
| S32550 | S32550 | 1.4507 | Super duplex | 39 | Acid and chloride process tubes |
What Is the Difference Between Super Duplex Welded Tubes and Super Duplex Seamless Tubes?
The short answer: welded tubes are rolled from strip and have one weld seam, made without filler metal and then solution annealed. Seamless tubes are pierced from a billet and have no seam. Welded super duplex tubes cost less and have a very even wall. Seamless is the choice for the smallest bores and the highest pressure.
| Question | Super Duplex Welded Tubes | Super Duplex Seamless Tubes |
|---|---|---|
| How is it made? | Strip is rolled and welded, then annealed | Billet is pierced and drawn |
| Is there a seam? | One, treated by solution annealing | None |
| How even is the wall? | Very even, from rolled strip | Can vary more |
| What does it cost? | Lower | Higher |
| How fast can it ship? | Often faster | Often slower |
| Does the design code add a weld factor? | Yes, set by the code | No |
| Where is it best? | Hot-seawater coolers, exchangers, moderate-pressure lines | Small bore, highest pressure, subsea control lines |
Super Duplex Welded Tubes Chemical Composition
Chemistry gives super duplex its pitting resistance. The table shows ASTM A789 limits, with the role of each element in the last column. Values are percentage by weight, maximum unless shown as a range.
| Element | S32750 | S32760 | S32550 | What it does |
|---|---|---|---|---|
| Chromium (Cr) | 24.0–26.0 | 24.0–26.0 | 24.0–27.0 | Builds the protective surface film |
| Molybdenum (Mo) | 3.0–5.0 | 3.0–4.0 | 2.9–3.9 | Raises pitting resistance |
| Nitrogen (N) | 0.24–0.32 | 0.20–0.30 | 0.10–0.25 | Adds strength and pitting resistance |
| Nickel (Ni) | 6.0–8.0 | 6.0–8.0 | 4.5–6.5 | Balances the austenite phase |
| Copper (Cu) | 0.50 max | 0.50–1.00 | 1.50–2.50 | Helps in acid service |
| Tungsten (W) | — | 0.50–1.00 | — | Adds pitting and crevice resistance |
| Manganese (Mn) | 1.20 | 1.00 | 1.50 | Kept limited |
| Silicon (Si) | 0.80 | 1.00 | 1.00 | Kept limited |
| Carbon (C) | 0.030 | 0.030 | 0.040 | Kept low to avoid carbides |
| Phosphorus (P) | 0.035 | 0.030 | 0.040 | Kept low for toughness |
| Sulphur (S) | 0.020 | 0.010 | 0.030 | Kept low for corrosion resistance |
Super Duplex Welded Tubes Mechanical Properties
Mechanical properties show the strength of the tube after solution annealing. The table gives minimum values for the parent metal.
| Grade | Yield min, MPa (ksi) | Tensile min, MPa (ksi) | Elongation min (%) | Hardness max |
|---|---|---|---|---|
| S32750 | 550 (80) | 800 (116) | 15 | 310 HBW |
| S32760 | 550 (80) | 750 (109) | 25 | — |
| S32550 | 550 (80) | 760 (110) | 15 | — |
Welded tube also takes weld tests, such as a flattening test across the seam. Eddy current or hydrostatic testing checks every tube.
Super Duplex Welded Tubes Size and Weight Chart
Weight depends on OD and wall thickness. Super duplex has a density of about 7.80 g/cm³, so we use this formula:
OD and wall are in mm. Example: a 31.75 mm OD tube with a 2.0 mm wall weighs (31.75 − 2.0) × 2.0 × 0.02450 = 1.46 kg/m. All figures below are in kg/m.
| OD (mm) | OD (in) | 1.2 mm wall | 1.5 mm wall | 2.0 mm wall | 2.5 mm wall | 3.0 mm wall |
|---|---|---|---|---|---|---|
| 19.05 | 3/4" | 0.52 | 0.64 | 0.84 | 1.01 | 1.18 |
| 25.4 | 1" | 0.71 | 0.88 | 1.15 | 1.40 | 1.65 |
| 31.75 | 1-1/4" | 0.90 | 1.11 | 1.46 | 1.79 | 2.11 |
| 38.1 | 1-1/2" | 1.08 | 1.35 | 1.77 | 2.18 | 2.58 |
| 44.5 | 1-3/4" | 1.27 | 1.58 | 2.08 | 2.57 | 3.05 |
| 50.8 | 2" | 1.46 | 1.81 | 2.39 | 2.96 | 3.51 |
| 63.5 | 2-1/2" | 1.83 | 2.28 | 3.01 | 3.74 | 4.45 |
| 76.2 | 3" | 2.21 | 2.75 | 3.64 | 4.51 | 5.38 |
Available Sizes, Dimensions and Tolerances
Super Duplex Welded Tubes are ordered by OD, wall and length. The chart above covers OD 19.05 to 76.2 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 range (mm) | OD tolerance (±mm) |
|---|---|
| Under 25.4 | 0.10 |
| 25.4 to 38.1 | 0.15 |
| Over 38.1 to under 50.8 | 0.20 |
| 50.8 to under 63.5 | 0.25 |
| 63.5 to under 76.2 | 0.30 |
| 76.2 to 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 Super Duplex Welded Tubes
We manufacture and supply Super Duplex Welded Tubes in grades selected for high-strength service and demanding corrosive environments. Our commonly supplied materials include:
UNS S32750 (1.4410): Super Duplex 2507 with around 25% chromium and 4% molybdenum, suitable for hot seawater, desalination, offshore and sour-service applications.
UNS S32760 (1.4501): Super duplex grade containing tungsten and copper, used for aggressive chloride environments and offshore applications where enhanced corrosion resistance is required.
UNS S32550 (1.4507): Copper-bearing super duplex grade used for selected acid and chloride process tubes, offering a useful balance of strength and corrosion resistance.
As Super Duplex Welded Tubes Suppliers, we provide these grades in different tube sizes, wall thicknesses, lengths and finishes according to the required specification and application.
Super Duplex Welded Tubes We Manufacture and Supply
We make Super Duplex Welded Tubes for the jobs below. The grade and finish follow the duty.
| Service | Grades | Tube form |
|---|---|---|
| Hot-seawater heat exchangers and coolers | S32750, S32760 | Straight or U-bend |
| Desalination exchangers | S32750, S32760 | Straight, cold drawn |
| Chemical injection and control lines | S32750 | Cold drawn, bright annealed |
| Acid and chloride process exchangers | S32550, S32750 | Straight, cold drawn |
| Firewater and cooling lines | S32750, S32760 | Straight |
Applications of Super Duplex Welded Tubes
- Heat exchangers and coolers: Shell and tube bundles running on hot seawater.
- Desalination plants: Brine heaters and high-pressure seawater tubes.
- Oil and gas: Produced-water coolers, injection and instrument lines, within NACE limits.
- Offshore platforms: Firewater, cooling and seawater tubing.
- Chemical and petrochemical plants: Exchangers carrying chloride or acid fluids.
- Marine: Scrubber and cooling systems on ships.
- Pulp and paper mills: Liquor heaters and bleach plant tubing.
- Power generation: Seawater-cooled condensers and flue gas desulphurisation tubing.
Why Choose Us as Your Super Duplex Welded Tubes Manufacturer in India?
Choosing the right manufacturer matters when welded tubes are required for corrosive and demanding service. Our experience since 2005 gives us a practical understanding of duplex and super duplex tube requirements, including grade selection, dimensions, wall thickness and finishing needs. We manufacture and supply UNS S32750, S32760 and S32550 Super Duplex Welded Tubes, with commonly requested sizes available from ready stock, subject to availability.
As a Super Duplex Welded Tubes Supplier in India, we also support the quality and documentation side of the order. Every order comes with an EN 10204 3.1 certificate, while 3.2 certification and third-party inspection can be arranged on request. Our ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certifications, together with PED 2014/68/EU and TUV approvals, support our quality management practices. We can manufacture and supply up to 100 tons per month, depending on grade, size and order requirements, and our products are shipped to 85+ countries.
Countries We Export Super Duplex Welded Tubes To
As a Super Duplex Welded Tubes Manufacturer, we supply our products from India to 85+ countries across major industrial markets. Our export process covers order coordination, product specifications, quality documents, export packing and shipment arrangements, helping international customers source super duplex welded tubes directly from India.
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 international orders, we prepare the required export documentation and packing based on the destination and order requirements. EN 10204 3.1 certification is supplied with every order, while 3.2 certification and third-party inspection are available on request. Our Mumbai export office coordinates shipments, while our manufacturing facility near Mumbai supports the production and supply of the required tube specifications.
Super Duplex Welded Tubes FAQs
Common questions about super duplex welded tube grades, weld seams, seawater service, U-bends, and supply.
Which super duplex grade should I choose for welded tubes?
S32750 is the usual choice and the most widely stocked. Pick S32760 when your project specification names it, and S32550 where copper helps in acid service.
Is the weld seam as corrosion resistant as the tube?
Yes, when the tube is welded correctly and solution annealed afterwards. With no filler metal, the seam has the same chemistry as the strip, and the anneal restores the phase balance.
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 and 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 smallest bores and the highest pressure.
What is the maximum service temperature?
Keep super duplex below about 250°C. Long exposure at higher temperatures can make it brittle. Your engineer should check the limit for the grade and code.
Can welded super 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.
Can the tubes be expanded into a tubesheet or welded to it?
Yes. Super duplex tubes are rolled or welded into tubesheets in practice. Use a qualified procedure and a compatible tubesheet material, and control heat input when welding.
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 19.05 to 76.2 mm in walls from 1.2 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 Super Duplex Welded Tubes?
Grade is the main factor, because nickel, molybdenum, chromium and nitrogen content move the cost. OD, wall, finish, length, testing, inspection, quantity and freight also count.
Which certificates and tests come with the tubes?
Each order carries an EN 10204 3.1 certificate showing chemistry and mechanical results. A 3.2 certificate, third-party inspection and ASTM A923 or G48 tests 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 Super Duplex Welded Tubes?
We are both. We manufacture near Mumbai and supply ready stock of popular sizes from the same location, subject to availability.
Do you export Super Duplex 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.