Duplex Steel UNS S31803 Pipes Manufacturer & Supplier
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Duplex Steel UNS S31803 pipes combine the best ferritic and austenitic stainless steels. Because of their dual-phase structure, they have great corrosion resistance and mechanical strength. It is ideal for use in harsh situations, such as oil and gas, marine and chemical industries. They operate effectively under pressure and survive longer in harsh environments. They are a good option for demanding applications because of their resistance to corrosion, stress and cracking. Midland Alloys Inc. stands as a trusted duplex S31803 pipe manufacturer in India. We provide these pipes in seamless, welded, and ERW forms. You can request customized sizes, finishes, and packaging. We also support fast global deliveries with complete export-ready solutions. As a leading duplex pipe manufacturer in India, we keep our focus on performance, durability, and reliable service at every step.
What Is Duplex Steel UNS S31803 Pipe?
Duplex Steel UNS S31803 is a type of duplex stainless steel pipe. It has a mixed structure of austenite and ferrite. This dual-phase balance gives it strong resistance to stress corrosion cracking. It also boosts strength and toughness, compared to regular stainless steel. This ASTM A790 UNS S31803 pipe meets the ASTM A790 standard, which covers seamless and welded pipes made from duplex stainless steel. These pipes are a common choice when durability matters during pipe production. The S31803 duplex stainless steel pipe is made from a blend of nickel, chromium, molybdenum, and nitrogen. This mix helps it handle tough environments without breaking down. The difference is minor; S32205 has tighter chemical limits, but both are often used interchangeably.
Key Features & Benefits
- Excellent resistance to pitting and crevice corrosion: One of the duplex S31803 pipe benefits is the high levels of chromium and molybdenum. It protects the pipe from deep, localized corrosion and makes it crucial in places with saltwater, chemicals or tight corners where moisture can sit.
- High mechanical strength: Duplex S31803 offers almost double the strength of common austenitic stainless steels. It can handle higher pressure and stress with thinner walls, which lowers both weight and material cost.
- Superior resistance to stress corrosion cracking: Chloride-rich settings, like coastal plants or chemical tanks can cause sudden cracking in other steels, but Duplex S31803 resists well. Its dual-phase structure hold up against both mechanical and chemical stress. This is one of the most valuable advantages of UNS S31803 pipe, especially for long term safety.
- Balanced ferrite-austenite structure: The structure gives the pipe strong toughness and dimensional stability. It holds its shape under pressure and doesn’t become brittle in low temperatures. This balance helps the pipe stay reliable across different conditions, such as hot, cold, wet, or dry.
- Good weldability and formability: Duplex S31803 is easy to cut, bend, and weld. This means less work and fewer defects during fabrication. Whether you’re manufacturing complex shapes or durable pipe that fits well and performs without extra effort. This reduces project delays and lowers the risk of rework.
- Cost-effective alternative to Super Duplex: While Super Duplex has higher performance, in some areas Duplex S31803 works well in most everyday applications. It gives you strength and corrosion resistance at a lower cost.
- Ideal for moderately aggressive conditions: This pipe suits marine, chemical, and offshore environments where there’s regular contact with salt, moisture, or industrial fluids. It won’t fail under normal wear and tear, and it doesn’t need frequent replacement.
If you’re differentiating duplex vs austenitic stainless pipe, Duplex S31803 gives you more strength, better corrosion resistance, and a longer service life, without the high cost of premium alloys.
Duplex Steel S31803 Pipe Specifications
Seamless Pipe OD : ½″ NB – 16″ NB
Welded Pipe OD : ½″ NB – 24″ NB
EFW Pipe Size : 6″ NB – 24″ NB
ASTM A790 ASME SA790
Seamless, ERW, Welded, Fabricated
Round, Square, Rectangular, Hydraulic Etc
Single Random, Double Random & Cut Length.
Plain End, Beveled End, Treaded
SCH5, SCH10, SCH20, SCH30, SCH40, STD, SCH80, SCH 80S, SCH60, SCH80, SCH120, SCH140, SCH160, SCH XXS, SCH XS
No. 2B – Mill finish / Matte finish, No. 4 – Brushed finish, No. 8 – Mirror finish, Bright Annealed – Smooth / Slightly reflective, Polished – Smooth / Enhanced corrosion resistance,Mirror – Highly reflective,
Types of Duplex UNS S31803 Pipes
Duplex Steel UNS S31803 pipes are available in various types based on how they’re manufactured and shaped. These variations help meet different flow, pressure, and structural needs across a wide range of industrial systems.
Manufacturing Types
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Seamless PipeThey are made from a solid billet and formed without any welds, offering a clean, uniform finish.
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Welded PipeIt is manufactured by rolling and welding steel strips along a straight seam.
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ERW (Electric Resistance Welded) PipeThese pipes are produced by applying an electric current to join the edges under pressure.
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EFW (Electric Fusion Welded) PipeEFW pipes are made by melting the edges using electric fusion, ideal for large-diameter or high-alloy applications.
Pipe Forms
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Round PipeThis pipe is most typically used in piping systems that convey liquids and gasses. Its shape promotes uniform pressure distribution and smooth flow.
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Square PipeIt is used in construction and structural applications. The shape provides strength and allows for easy alignment in frames.
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Rectangular PipeIdeal for applications needing flat surfaces and edge support. Common in frames, racks, and support structures.
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Hydraulic PipeSpecifically designed for high-pressure fluid flow in hydraulic systems. Offers tight tolerances and strong burst resistance.
Each form type is selected based on system layout, space and design specifications, assuring the best fit for the work.
Contact us today to discuss how Duplex UNS S31803 Pipes can benefit your application. Whether you need guidance in selecting the right pipes or have specific requirements, our team of experts is here to help you find the optimal solution.
Technical Details & Delivery Condition
UNS S31803’s performance is because of its balanced alloy composition which is intended to provide strength and corrosion resistance. Chromium, nickel, molybdenum and nitrogen are essential elements. This precise composition is controlled under the ASTM A790 standard to ensure consistent pipe quality.
| Material | C | N | P | Si | Mn | Mo | Fe | Cr | S | Ni |
| Duplex UNS S31803 Pipe | 1.0 | 0.03 | 0.02 | 2.0 | 3.0 – 3.5 | 22.0 – 23.0 | 0.03 | 4.5 – 6.5 | 0.14 – 0.2 | Balance |
Duplex Steel S31803 pipes offer greater strength than standard austenitic stainless steels like SS 304 and 316. Due to their dual-phase microstructure, they resist stress, pressure and cracking more effectively in demanding conditions.
| Material | Density | Melting Point | Yield Strength (0.2% Offset) | Tensile Strength | Elongation |
| Duplex UNS S31803 Pipe | 7.8 g/cm³ | 1350 °C (2460 °F) | 80,000 psi / 550 MPa | 116,000 psi / 800 MPa | 15% |
Duplex Steel UNS S31803 has several equivalent grades recognized under global material standards. While their chemical compositions differ slightly, these grades are used interchangeably in a variety of industrial applications.
| Material | Density | Melting Point | Yield Strength (0.2% Offset) | Tensile Strength | Elongation |
| Duplex UNS S31803 Pipe | 7.8 g/cm³ | 1350 °C (2460 °F) | 80,000 psi / 550 MPa | 116,000 psi / 800 MPa | 15% |
Duplex S31803 Pipe Performance in Real Environments
Duplex & Super Duplex Steel Pipes Grades We Offer
Duplex Steel UNS S31803 Pipe Schedule
| Nominal Pipe Size | Available Schedules | Nominal Pipe Size | Available Schedules |
| 1/8″ IPS (0.405″ O.D.) | Seamless Pipes, SCH 40, 80 | 3-1/2″ IPS (4.000″ O.D.) | Pipes, SCH 10, 40, 80, 160, XXH |
| 1/4″ IPS (0.540″ O.D.) | Pipes, SCH 10, 40, 80 | 4″ IPS (4.500″ O.D.) | Seamless Pipes, SCH 10, 40, 80, 160, XXH |
| 3/8″ IPS (0.675″ O.D.) | Seamless Pipes, SCH 10, 40, 80 | 5″ IPS (5.563″ O.D.) | Pipes, SCH 10, 40, 80, 160, XXH |
| 1/2″ IPS (0.840″ O.D.) | Seamless Pipes, SCH 5, 10, 40, 80, 160, XXH | 6″ IPS (6.625″ O.D.) | Seamless Pipes, SCH 5, 10, 40, 80, 120, 160, XXH |
| 3/4″ IPS (1.050″ O.D.) | Pipes, SCH 10, 40, 80, 160, XXH | 8″ IPS (8.625″ O.D.) | Stainless Pipes, SCH 5, 10, 40, 80, 120, 160, XXH |
| 1″ IPS (1.315″ O.D.) | Seamless Pipes, SCH 5, 10, 40, 80, 160, XXH | 10″ IPS (10.750″ O.D.) | Pipes, SCH 10, 20, 40, 80 (.500), TRUE 80 (.500) |
| 1-1/4″ IPS (1.660″ O.D.) | Seamless Pipes, SCH 10, 40, 80, 160, XXH | 12″ IPS (12.750″ O.D.) | Pipes, SCH 10, 20, 40 (.375), TRUE 40 (.406), SCH 80 (.500) |
| 1-1/2″ IPS (1.900″ O.D.) | Seamless Pipes, SCH 10, 40, 80, 160, XXH | 14″ IPS (14.000″ O.D.) | Pipes, SCH 10 (.188), SCH 40 (.375) |
| 2″ IPS (2.375″ O.D.) | Seamless Pipes, SCH 10, 40, 80, 160, XXH | 16″ IPS (16.000″ O.D.) | Pipes, SCH 10 (.188), SCH 40 (.375) |
| 2-1/2″ IPS (2.875″ O.D.) | Seamless Pipes, SCH 10, 40, 80, 160, XXH | 18″ IPS (18.000″ O.D.) | Pipes, SCH 40 (.375) |
| 3″ IPS (3.500″ O.D.) | Seamless Pipes, SCH 5, 10, 40, 80, 160, XXH | — | — |
Duplex Steel UNS S31803 Pipe Weight Chart
| Outside Dia (mm) | Wall Thk (mm) | in. | Schedule | Kg/m |
|---|---|---|---|---|
| 13.72 | 1.65 | 1/4 | 10S | 0.50 |
| 13.72 | 2.24 | 1/4 | 40S | 0.64 |
| 13.72 | 3.02 | 1/4 | 80S | 0.81 |
| 17.15 | 1.65 | 3/8 | 10S | 0.64 |
| 17.15 | 2.31 | 3/8 | 40S | 0.86 |
| 17.15 | 3.20 | 3/8 | 80S | 1.12 |
| 21.34 | 2.11 | 1/2 | 10S | 1.02 |
| 21.34 | 2.77 | 1/2 | 40S | 1.29 |
| 21.34 | 3.73 | 1/2 | 80S | 1.65 |
| 26.67 | 2.11 | 3/4 | 10S | 1.30 |
| 26.67 | 2.87 | 3/4 | 40S | 1.71 |
| 26.67 | 3.91 | 3/4 | 80S | 2.23 |
| 33.40 | 2.77 | 1 | 10S | 2.13 |
| 33.40 | 3.38 | 1 | 40S | 2.54 |
| 33.40 | 4.55 | 1 | 80S | 3.29 |
| 33.40 | 6.35 | 1 | 160 | 4.30 |
| 42.16 | 2.77 | 1¼ | 10S | 2.73 |
| 42.16 | 3.56 | 1¼ | 40S | 3.44 |
| 42.16 | 4.85 | 1¼ | 80S | 4.53 |
| 42.16 | 6.35 | 1¼ | 160 | 5.69 |
| 48.26 | 2.77 | 1½ | 10S | 3.16 |
| 48.26 | 3.68 | 1½ | 40S | 4.11 |
| 48.26 | 5.08 | 1½ | 80S | 5.49 |
| 60.33 | 2.77 | 2 | 10S | 3.99 |
| 60.33 | 3.91 | 2 | 40S | 5.52 |
| 60.33 | 5.54 | 2 | 80S | 7.60 |
| 60.33 | 8.74 | 2 | 160 | 11.29 |
| 73.03 | 3.05 | 2½ | 10S | 5.35 |
| 73.03 | 5.16 | 2½ | 40S | 8.77 |
| 73.03 | 7.01 | 2½ | 80S | 11.59 |
| 88.90 | 3.05 | 3 | 10S | 6.56 |
| 88.90 | 5.49 | 3 | 40S | 11.47 |
| 88.90 | 7.62 | 3 | 80S | 15.51 |
| 88.90 | 11.13 | 3 | 160 | 21.67 |
| 101.60 | 3.05 | 3½ | 10S | 7.53 |
| 101.60 | 5.74 | 3½ | 40S | 13.78 |
| 101.60 | 8.08 | 3½ | 80S | 18.92 |
| 114.30 | 3.05 | 4 | 10S | 8.50 |
| 114.30 | 6.02 | 4 | 40S | 16.32 |
| 114.30 | 8.56 | 4 | 80S | 22.67 |
| 114.30 | 13.49 | 4 | 160 | 34.05 |
| 141.30 | 6.55 | 5 | 40S | 22.10 |
| 141.30 | 9.53 | 5 | 80S | 31.44 |
| 141.30 | 15.88 | 5 | 160 | 49.87 |
| 168.28 | 3.40 | 6 | 10S | 14.04 |
| 168.28 | 7.11 | 6 | 40S | 28.69 |
| 168.28 | 10.97 | 6 | 80S | 43.21 |
| 168.28 | 14.27 | 6 | 120 | 54.75 |
| 168.28 | 18.26 | 6 | 160 | 68.59 |
| 219.08 | 8.18 | 8 | 40S | 43.20 |
| 219.08 | 12.70 | 8 | 80S | 65.63 |
| 219.08 | 18.23 | 8 | 120 | 91.30 |
| 219.08 | 23.01 | 8 | 160 | 112.97 |
The duplex S31803 pipe price per kg in India depends on a few things such as pipe type, size, wall thickness, and finish. Seamless pipes cost more because they need complex production methods. Welded pipes are more budget friendly, and work well for non-critical use. On average, the UNS S31803 pipe price in India ranges from ₹450 to ₹750 per kg, based on the form and dimensions. Rates shift with changes in raw materials, like nickel and molybdenum. Custom cut lengths, polishing or NACE-compliant pipes can change the base price.
The final cost is additionally affected by other elements such as export documentation, and the minimum order quantity (MOQ). The ASTM A790 S31803 pipe cost depends on the finish and testing requirements. For general reference, the pricing of duplex stainless steel 2205 pipe remains consistent unless you request specific grades or bulk quantities.
How Duplex Steel UNS S31803 Pipes Are Manufactured
Round Bar
Analytic
Cut to Length
Centering
Heating
Perforation
Inspection of Size
Pickling
Inspection of Surface
Lubricating
Cold Drawing (Cold Rolling)
Degreasing
Annealing
Straightening
Cut
Pickling / Passivating
Inspection
Analytic
Marking
Packing & Shipping
Applications of UNS S31803 Pipes
The Duplex S31803 pipes go through strict quality control tests during and after production. These measures ensure that the pipes fulfill international requirements. We conduct non-destructive tests (NDT) to detect internal faults or welding concerns. These include hydrostatic pressure testing, radiographic testing, and ultrasonic testing. These methods help spot hidden problems without damaging the pipe. We also employ Positive Material Identification (PMI) for identifying the material grade. This guarantees that each pipe has the necessary chemical composition. Before shipping we check every pipe for dimensional accuracy and perform visual inspections. This final step helps catch surface issues or size mismatches.
Each pipe comes with a Mill Test Certificate (MTC) as per EN 10204 3.1 or 3.2. If needed, we provide third-party inspection of duplex pipes by trusted global agencies like TÜV, DNV, or SGS. Our duplex S31803 pipe meets ASTM A790 pipe certification. We meet ISO 9001 standards and comply with all major piping codes.
Duplex S31803 pipes are available with a variety of surface treatments to meet varied purposes, such as industrial, hygienic or marine application. The most common is the mill finish, which is the as-produced surface. For better cleanability, the pickled finish duplex stainless steel pipe is ideal as it removes scale and improves corrosion resistance. Polished duplex 2205 pipe surfaces are also available upon request, mostly for food, pharmaceutical and cosmetic uses. Duplex steel pipe end customization includes plain, beveled, or threaded ends to suit installation needs. You can also customize the wall thickness and exterior diameter to meet your exact specifications. To ensure the pipes’ optimal protection throughout travel, shipping and export packaging options include plastic-capped ends, HDPE wrapping, and strong hardwood boxes.
Why Choose Midland Alloys Inc. for Duplex S31803 Pipes
Midland Alloys Inc. is a trusted duplex S31803 pipe supplier in India, known for reliable quality and consistent performance. We export globally with full documentation support and proven delivery experience. Customers trust us for project-based consultation, fast communication, and flexible production to match their timelines. We maintain a ready stock of S31803 pipe with fast delivery options for urgent needs. As a custom duplex pipe manufacturer, we offer cut-to-length services, client-specific branding, and fabrication based on your exact needs. We offer secure packaging, on-time dispatch, and quick responses to bulk or urgent inquiries to ensure a smooth and reliable buying experience. Every order is handled with secure packaging, timely dispatch, and fast response to bulk or time-sensitive inquiries, making us a reliable partner for critical supply needs.
Frequently Asked Questions About Duplex S31803 pipes
UNS S31803 is a duplex stainless steel that combines the properties of austenitic and ferritic stainless steels. It offers excellent corrosion resistance, high strength, and good weldability, making it ideal for use in harsh environments.
S32205 is an improved version of S31803. While both are duplex stainless steels, S32205 has a more tightly controlled chemical composition, which provides enhanced corrosion resistance, especially to pitting and crevice corrosion.
Yes, S31803 is suitable for seawater in moderate conditions, but for continuous or aggressive exposure, super duplex grades are better.
The price of S31803 pipe per kg can vary depending on market conditions, size, and supplier. For the latest pricing, it’s best to consult a trusted duplex S31803 pipe supplier or check live market rates.
Duplex S31803 has nearly twice the yield strength of 316 stainless steel, along with better resistance to stress corrosion cracking and pitting. While 316 is preferred for ease of fabrication and general corrosion resistance, S31803 is chosen for high-strength and more demanding environments.
