Duplex Seamless Pipe Manufacturer in India
Duplex Seamless Pipe Manufacturer in India
Sachiya Steel International is a leading Duplex Seamless Pipe Manufacturer in India, manufacturing and supplying pipes and tubes since 2005. With a facility near Mumbai and an export office in Mumbai, we cater to domestic and international requirements for duplex stainless steel pipes used in marine, offshore, chemical processing, oil and gas, and industrial applications.
Our product range includes duplex grades such as UNS S31803, UNS S32205 and UNS S32750, subject to specifications and availability. We supply pipes in various outside diameters, wall thicknesses, schedules and lengths according to applicable ASTM and ASME standards. Every order includes an EN 10204 Type 3.1 certificate, with Type 3.2 documentation and third-party inspection available on request. With ISO certifications, PED 2014/68/EU and TUV approvals, ready stock of popular sizes subject to availability, and exports to 85+ countries, we support buyers with material documentation and international supply coordination.
What Are Duplex Seamless Pipes?
Duplex seamless pipes are stainless steel pipes made from duplex steel, a grade with a two-phase structure of about half austenite and half ferrite. The pipe is pierced from a solid billet, so it has no weld seam, and it is solution annealed and quenched to lock in the right balance of the two phases.
The mixed structure gives duplex the best of both families. The ferrite brings high strength and resistance to chloride stress corrosion cracking. The austenite brings toughness and good weldability. Chromium of 21% to 24%, molybdenum and nitrogen add resistance to pitting and crevice corrosion. The most common grade, 2205, has a pitting resistance equivalent number (PREN) of about 35, against about 24 for 316L. PREN is a rough index of pitting resistance: Cr + 3.3 × Mo + 16 × N. Pipes are ordered by nominal pipe size (NPS) and schedule, or by OD and wall in mm.
Duplex Seamless Pipes
High-quality Duplex Seamless Pipes manufactured for demanding applications across oil & gas, petrochemical, chemical, marine, power generation and engineering industries. Available in various sizes, grades, wall thicknesses and manufacturing specifications.
Types of Duplex Seamless Pipes
We are a trusted Duplex Seamless Pipe Manufacturer, offering pipes in different grades, schedules, wall thicknesses and finishes for industrial applications.
- 2205 Duplex Seamless Pipes (S31803, S32205): Used in oil and gas, chemical processing and marine industries.
- 2304 Lean Duplex Seamless Pipes (S32304): Suitable for moderate corrosion conditions and cost-effective industrial piping.
- 2101 Lean Duplex Seamless Pipes (S32101): Features low nickel and molybdenum content with nitrogen-enhanced strength.
- Hot-Finished Duplex Seamless Pipes: Available in larger diameters and thicker wall sections.
- Cold-Drawn Duplex Seamless Pipes: Offers precise dimensions and a smooth surface finish.
- Thin-Wall Duplex Seamless Pipes: Available in Sch 10S and Sch 40S for lightweight piping requirements.
- Heavy-Wall Duplex Seamless Pipes: Available in Sch 80S and Sch 160 for high-pressure applications.
- Solution-Annealed and Pickled Duplex Seamless Pipes: Supplied with heat treatment and a clean, corrosion-resistant surface.
- Plain-End and Bevelled-End Duplex Seamless Pipes: Available with end finishes suitable for installation and butt welding.
S31803, S32205, S32304 and S32101 Duplex Seamless Pipe Manufacturers and Suppliers in India
We manufacture and supply Duplex Seamless Pipe in four grades. The right one depends on chloride level, temperature and cost.
- UNS S31803 (2205): the original 2205 grade, with high strength and strong resistance to pitting and stress corrosion cracking. Used in oil and gas, chemical processing and marine systems.
- UNS S32205 (2205): the improved 2205 with tighter chromium, molybdenum and nitrogen limits, which gives more consistent corrosion resistance. It is now the usual 2205 purchase grade.
- UNS S32304 (2304): a lean duplex with less molybdenum, suited to moderate chloride service in tanks, water and general process lines.
- UNS S32101 (2101): a lean duplex with low nickel and high manganese and nitrogen, chosen for structural and cost-sensitive duty.
These grades are available in different outside diameters, wall thicknesses, schedules and end finishes according to the required specification.
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Duplex Seamless Pipe Specification
The table sets out the working specification.
| Item | Detail |
|---|---|
| Product | Duplex Seamless Pipe |
| Process | Seamless, hot finished or cold drawn |
| Grades | S31803, S32205, S32304, S32101 |
| Pipe standards | ASTM A790 / ASME SA790, EN 10216-5 |
| General requirements | ASTM A999 |
| Dimensions | ASME B36.19M (Sch 10S, 40S, 80S), ASME B36.10M (Sch 160 and other walls) |
| Size reference | NPS 1/2 to 12 in the tables, other sizes on request |
| Length | Single random, double random or cut length |
| Ends | Plain or bevelled (ASME B16.25) |
| Heat treatment | Solution annealed and quenched |
| Surface | Pickled and passivated |
| Tests | Chemical analysis, tensile, hardness, flattening, hydrostatic or non-destructive test; ASTM A923 and ASTM G48 on request |
| Certificate | EN 10204 3.1 with every order, 3.2 on request |
| Inspection | Third-party inspection on request |
Duplex Seamless Pipe Standards and Specifications
Duplex pipe is bought to a pipe standard, with test methods and sour-service rules behind it. The table links each one to its job.
| Standard | Covers | Applies to |
|---|---|---|
| ASTM A790 / ASME SA790 | Seamless and welded ferritic/austenitic stainless steel pipe | Core duplex pipe standard |
| ASTM A789 / ASME SA789 | Seamless and welded ferritic/austenitic stainless steel tubing | Duplex tube |
| ASTM A999 | General requirements for alloy and stainless steel pipe | Tolerances and test rules |
| EN 10216-5 | Seamless stainless steel tubes for pressure purposes | European projects |
| ASTM A923 | Test methods for detrimental intermetallic phases | Structure check, Method A, B or C |
| ASTM G48 | Pitting and crevice corrosion test in ferric chloride | Corrosion check |
| NACE MR0175 / ISO 15156-3 | Materials for sour service, CRAs | Oil and gas projects |
| ASTM A182 | Forged fittings and flanges, F51 (S31803), F60 (S32205) | Matching forgings |
| ASTM A815 | Wrought ferritic, ferritic/austenitic and martensitic fittings | Matching butt-weld fittings |
| ASME B36.19M and B36.10M | Pipe dimensions and weights | OD and wall reference |
| ASME B16.25 | Butt-welding ends | Bevel angle and root face |
| EN 10204 | Types of inspection documents | 3.1 and 3.2 certificates |
Duplex Seamless Pipe Material and Grades
Pick the grade by the chloride level, the temperature and the cost target. The table lists the grades with their UNS and EN numbers.
| Grade | UNS | EN number | Name | PREN (about) | Matching forging | Typical use |
|---|---|---|---|---|---|---|
| S31803 | S31803 | 1.4462 | Duplex 2205 | 35 | A182 F51 | Oil and gas, chemical, marine |
| S32205 | S32205 | 1.4462 | Duplex 2205 | 35 | A182 F60 | Same service, tighter chemistry |
| S32304 | S32304 | 1.4362 | Lean duplex 2304 | 25 | A182 F? (per project) | Tanks, water, moderate chloride |
| S32101 | S32101 | 1.4162 | Lean duplex 2101 | 26 | Per project | Structural and cost-driven duty |
What Is the Difference Between Duplex Seamless Pipe and Stainless Steel 316L Seamless Pipe?
The short answer: duplex has about double the strength of 316L and far better resistance to chloride cracking and pitting, which lets walls be thinner and service life longer. Use 316L for mild service, and duplex where chlorides, pressure or weight matter.
| Point | Duplex Seamless Pipe (2205) | 316L Seamless Pipe |
|---|---|---|
| Structure | About 50% austenite, 50% ferrite | Austenite |
| Chromium | 22 to 23% | 16 to 18% |
| Nickel | 4.5 to 6.5% | 10 to 14% |
| Molybdenum | 3.0 to 3.5% | 2.0 to 3.0% |
| PREN | About 35 | About 24 |
| Yield strength, min | 450 MPa | 170 MPa |
| Chloride stress cracking | High resistance | Can crack |
| Temperature limit | Keep below about 300 °C | Higher |
| Cost | Higher per kg, often lower per metre with a thinner wall | Lower per kg |
| Typical use | Chloride service, high pressure, offshore | General process, food, mild chemical |
Duplex Seamless Pipe Chemical Composition
Chemistry sets the duplex phase balance and corrosion resistance. The table shows the ASTM A790 limits, one element per row. Values are percentage by weight, maximum unless shown as a range.
| Element | S31803 | S32205 | S32304 | S32101 |
|---|---|---|---|---|
| Carbon (C) | 0.030 | 0.030 | 0.030 | 0.040 |
| Manganese (Mn) | 2.00 | 2.00 | 2.50 | 4.0–6.0 |
| Silicon (Si) | 1.00 | 1.00 | 1.00 | 1.00 |
| Phosphorus (P) | 0.030 | 0.030 | 0.040 | 0.040 |
| Sulphur (S) | 0.020 | 0.020 | 0.040 | 0.030 |
| Chromium (Cr) | 21.0–23.0 | 22.0–23.0 | 21.5–24.5 | 21.0–22.0 |
| Nickel (Ni) | 4.5–6.5 | 4.5–6.5 | 3.0–5.5 | 1.35–1.70 |
| Molybdenum (Mo) | 2.5–3.5 | 3.0–3.5 | 0.05–0.60 | 0.10–0.80 |
| Nitrogen (N) | 0.08–0.20 | 0.14–0.20 | 0.05–0.20 | 0.20–0.25 |
| Copper (Cu) | — | — | 0.05–0.60 | 0.10–0.80 |
Duplex Seamless Pipe Mechanical Properties
Mechanical properties are why duplex allows thin walls. The table gives minimum values under ASTM A790, one property per row.
| Property | S31803 | S32205 | S32304 | S32101 |
|---|---|---|---|---|
| Yield strength, MPa (ksi) | 450 (65) | 450 (65) | 400 (58) | 450 (65) |
| Tensile strength, MPa (ksi) | 620 (90) | 655 (95) | 600 (87) | 650 (94) |
| Elongation in 50 mm (%) | 25 | 25 | 25 | 30 |
| Hardness, max | 290 HBW | 290 HBW | 290 HBW | 290 HBW |
Duplex Seamless Pipe 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: NPS 4 Sch 40S is (114.3 − 6.02) × 6.02 × 0.02450 = 15.97 kg/m. Multiply by length for total weight. Walls for each schedule are listed in the next section.
| NPS | OD (mm) | Sch 10S (kg/m) | Sch 40S (kg/m) | Sch 80S (kg/m) | Sch 160 (kg/m) |
|---|---|---|---|---|---|
| 1/2" | 21.3 | 0.99 | 1.26 | 1.61 | 1.93 |
| 1" | 33.4 | 2.08 | 2.49 | 3.22 | 4.21 |
| 2" | 60.3 | 3.90 | 5.40 | 7.43 | 11.04 |
| 3" | 88.9 | 6.41 | 11.22 | 15.17 | 21.21 |
| 4" | 114.3 | 8.31 | 15.97 | 22.18 | 33.32 |
| 6" | 168.3 | 13.74 | 28.08 | 42.28 | 67.12 |
| 8" | 219.1 | 19.84 | 42.27 | 64.22 | 110.54 |
| 10" | 273.1 | 27.61 | 59.92 | 81.02 | 171.22 |
| 12" | 323.9 | 35.75 | 73.40 | 96.83 | 237.21 |
Available Sizes, Dimensions and Schedules
Duplex Seamless Pipe follows ASME B36.19M for Sch 10S, 40S and 80S, and ASME B36.10M for Sch 160. A schedule is a wall-thickness code, so for the same OD a higher number means a thicker wall. Because duplex is strong, your engineer may choose a lighter schedule than 316L would need. Confirm the wall against the design code. Other sizes and walls can be quoted on request.
| NPS | OD (mm) | Sch 10S (mm) | Sch 40S (mm) | Sch 80S (mm) | Sch 160 (mm) |
|---|---|---|---|---|---|
| 1/2" | 21.3 | 2.11 | 2.77 | 3.73 | 4.78 |
| 1" | 33.4 | 2.77 | 3.38 | 4.55 | 6.35 |
| 2" | 60.3 | 2.77 | 3.91 | 5.54 | 8.74 |
| 3" | 88.9 | 3.05 | 5.49 | 7.62 | 11.13 |
| 4" | 114.3 | 3.05 | 6.02 | 8.56 | 13.49 |
| 6" | 168.3 | 3.40 | 7.11 | 10.97 | 18.26 |
| 8" | 219.1 | 3.76 | 8.18 | 12.70 | 23.01 |
| 10" | 273.1 | 4.19 | 9.27 | 12.70 | 28.58 |
| 12" | 323.9 | 4.57 | 9.53 | 12.70 | 33.32 |
Tolerances follow ASTM A999. Wall may run up to 12.5% under nominal. The OD limit is +0.4 / −0.8 mm up to NPS 1-1/2, ±0.8 mm above that up to NPS 4, +1.6 / −0.8 mm from NPS 4 to 8, and +2.4 / −0.8 mm from NPS 8 to 18.
Common Materials in Duplex Seamless Pipe
We manufacture and supply the commonly specified materials used in Duplex Seamless Pipe, with grades selected according to chloride level, temperature, pressure and cost.
UNS S31803 (1.4462): The original 2205 duplex, with about 22% chromium and 3% molybdenum. It is widely used for oil and gas, chemical and marine lines.
UNS S32205 (1.4462): The refined 2205 with tighter limits on chromium, molybdenum and nitrogen, now the usual purchase grade.
UNS S32304 (1.4362): Lean duplex 2304, with low molybdenum, suited to tanks, water lines and moderate chloride service.
UNS S32101 (1.4162): Lean duplex 2101, with low nickel and high manganese and nitrogen for cost-driven duty.
These grades form part of our supply range as Duplex Seamless Pipe Suppliers, with different sizes, schedules, wall thicknesses and end finishes available according to the required specification.
Duplex Seamless Pipe We Manufacture and Supply
We make Duplex Seamless Pipe for the jobs below. The grade and wall follow the chloride level and the pressure.
| Service | Grades | Typical wall |
|---|---|---|
| Oil and gas flowlines and process piping | S31803, S32205 | Sch 40S to 160 |
| Seawater cooling and firewater systems | S32205 | Sch 10S to 40S |
| Desalination feed and brine lines | S32205, S32304 | Sch 10S to 40S |
| Chemical and acid process lines | S31803, S32205 | Sch 10S to 80S |
| Pulp and paper digester and liquor lines | S32205, S32304 | Sch 10S to 40S |
| Water treatment and storage tank piping | S32304, S32101 | Sch 10S to 40S |
Applications of Duplex Seamless Pipe
- Oil and gas: Flowlines, manifolds and process piping in chloride-rich service.
- Chemical and petrochemical plants: Acid, caustic and chloride process lines.
- Desalination plants: High-pressure reverse-osmosis feed and brine lines.
- Offshore platforms: Seawater, firewater and produced-water systems.
- Marine: Scrubber and seawater cooling systems on ships.
- Pulp and paper mills: Digester, bleach plant and liquor lines.
- Power generation: Flue gas desulphurisation and cooling water systems.
- Fertiliser plants: High-pressure process lines where strength and corrosion resistance both count.
- Water and wastewater: Pipelines and storage tanks in aggressive water.
Why Choose Us as Your Duplex Seamless Pipe Manufacturer in India?
We have been working in the pipes and tubes industry since 2005, which gives us close to two decades of experience with stainless steel and duplex requirements. Our facility near Mumbai supports the manufacturing and supply of UNS S31803, S32205, S32304 and S32101 Duplex Seamless Pipe in different outside diameters, wall thicknesses and schedules. Popular sizes can be available from ready stock, subject to availability. This experience makes us a dependable Duplex Seamless Pipe Supplier in India for demanding industrial applications.
Our quality and documentation practices support both domestic and international supply. EN 10204 3.1 certification is provided with every order, while 3.2 certification and third-party inspection can be arranged on request. We hold ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 certifications, together with PED 2014/68/EU and TUV approvals. With an export office in Mumbai and supply reaching 85+ countries, we also manage export packing, documentation and shipment for duplex pipe orders.
Countries We Export Duplex Seamless Pipe To
Our Duplex Seamless Pipe is supplied from India to 85+ countries, with export orders covering oil and gas, desalination, marine and chemical processing projects. We work with international specifications and arrange the required material documentation, inspection and shipment details for each order.
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, South Korea, Japan and Australia
North and South America: USA, Canada, Mexico and Brazil
Africa: South Africa, Nigeria, Egypt and Kenya
For overseas requirements, EN 10204 3.1 certification is supplied with every order. EN 10204 3.2 certification and third-party inspection can be arranged when specified. Export packing and shipping documentation are handled according to the order and destination, supporting the movement of duplex seamless pipe from India to international project locations.
Duplex Seamless Pipe FAQs
Common questions about duplex pipe grades, chloride service, temperature limits, testing, and supply.
Which duplex grade should I choose?
S32205 (2205) is the usual choice for chloride service, oil and gas and marine work. Pick lean duplex 2304 or 2101 for moderate chloride duty where cost matters, and pick super duplex when the water is hot or the fluid is sour.
When should I choose super duplex over standard duplex?
Choose super duplex when seawater is warm, chloride is high, the fluid is sour or the pressure calls for a thinner, stronger wall. For cool, mild chloride duty, 2205 is often enough.
Should I specify S31803 or S32205?
S32205 is the safer choice, because its tighter limits on chromium, molybdenum and nitrogen give more consistent corrosion resistance. Many suppliers dual-certify pipe to both, so state the grade your project specification names.
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.
Is duplex suitable for 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 I use a thinner wall than with 316L?
Often, yes. Duplex has more than double the yield strength of 316L, so many designs allow a lighter schedule. Confirm the wall against your design code and corrosion allowance.
What tolerances apply to OD and wall?
ASTM A999 sets them. Wall may run up to 12.5% under nominal, and OD limits depend on the pipe size.
What sizes can I order?
The tables above cover NPS 1/2 to 12 in Sch 10S, 40S, 80S and 160. Other sizes and walls can be quoted on request, and popular sizes sit in ready stock, subject to availability.
How do I calculate the weight of an 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 Seamless Pipe?
Grade is the main factor, because nickel, molybdenum, chromium and nitrogen content move the cost. Size, wall, finish, testing, quantity, inspection and freight also count.