Amigo Impex is a Duplex Steel Pipes & Tubes manufacturer, supplier, stockist and exporter based in Mumbai, India. Established in 2013, our company handles cutting, machining, threading, fabrication, testing and packing in-house. We supply Duplex S31803 Pipes & Tubes for industrial piping, heat exchanger, offshore, chemical-processing and fluid-handling applications.
Duplex S31803 is a ferritic-austenitic stainless steel containing both ferrite and austenite phases. It is commonly known as Duplex 2205 and is identified by UNS S31803. Its balanced chromium, nickel, molybdenum and nitrogen content provides good resistance to chloride-induced pitting, crevice corrosion and stress corrosion cracking, while its higher strength distinguishes it from conventional austenitic stainless steel grades.
Duplex S31803 pipe is supplied to ASTM A790 / ASME SA-790, while duplex tubing is supplied to ASTM A789 / ASME SA789. Dimensions can be supplied in accordance with ASME B36.19M and applicable B36.10M requirements. Seamless, welded construction options are available depending on size, specification and application.
Our Mumbai stock includes ready material for standard requirements, with custom cut lengths processed in-house. Every heat is supplied with material traceability and mill test certification. Company certifications and approvals include AS 9120B, ISO 9001:2015 and ISO 45001:2018, where applicable.
The duplex stainless steel pipe specification for an enquiry is established by the material grade, governing standard, dimensions, manufacturing route, length and end condition. The supplied grade on this page is Duplex S31803.
The product form determines the applicable material specification. Duplex S31803 pipe is covered by ASTM A790 / ASME SA-790, while tubing is covered by ASTM A789 / ASME SA789.
| Standard | Scope |
|---|---|
| ASTM A790 / ASME SA-790 | Seamless and welded ferritic/austenitic stainless steel pipe |
| ASTM A789 / ASME SA789 | Seamless and welded ferritic/austenitic stainless steel tubing for general service |
| ASME B36.19M | Stainless steel pipe dimensions and schedules |
| ASME B36.10M | Wrought steel pipe dimensions and heavier-wall schedules |
The supplied grade is Duplex S31803, commonly identified as Duplex 2205. The grade combines ferritic and austenitic phases to provide a useful balance of strength and corrosion resistance.
Duplex S31803 pipe is supplied in seamless and welded construction according to ASTM A790 / ASME SA-790. The material is selected for applications where chloride exposure, mechanical loading and general corrosion resistance need to be considered together.
Pipe is generally ordered by nominal pipe size and schedule, while tube is specified by outside diameter and wall thickness. Available dimensions depend on the applicable standard, manufacturing route and required material size.
| Dimension | Basis |
|---|---|
| Pipe OD and Wall | ASME B36.19M, including applicable stainless steel schedules |
| Heavy-Wall Pipe | Applicable ASME B36.10M dimensions |
| Tube OD and Wall | Exact outside diameter and specified wall/gauge |
| Length | Single random, double random or custom cut length |
A duplex stainless steel pipe schedule chart is used to identify wall thickness against nominal pipe size. Schedule selection should be checked against the applicable dimensional standard and the pressure-design requirements of the project.
| NPS | Typical Schedule Options |
|---|---|
| 3/4" | SCH 5S, 10S, 40S, 80S |
| 1" | SCH 5S, 10S, 40S, 80S |
| 3" | SCH 5S, 10S, 40S, 80S |
| 6" | SCH 5S, 10S, 40S, 80S |
For heavier wall requirements, dimensions may be specified against the applicable ASME B36.10M schedule.
Theoretical pipe weight depends on outside diameter, wall thickness and material density. The figures below are calculated values and should not be treated as certified shipping weights.
The theoretical calculation uses:
kg/m = 3.1416 × wall thickness × (OD − wall thickness) × density / 1000
where dimensions are in millimetres and density is taken as approximately 7.8 g/cm³.
| NPS | OD (mm) | SCH 40 Wall (mm) | SCH 40 kg/m | SCH 80 Wall (mm) | SCH 80 kg/m |
|---|---|---|---|---|---|
| 3/4" | 26.7 | 2.87 | 1.68 | 3.91 | 2.18 |
| 1" | 33.4 | 3.38 | 2.49 | 4.55 | 3.22 |
| 3" | 88.9 | 5.49 | 11.22 | 7.62 | 15.18 |
| 6" | 168.3 | 7.11 | 28.08 | 10.97 | 42.29 |
The pressure rating of a duplex stainless steel pipe is not determined by a single catalogue number. Design pressure depends on pipe diameter, wall thickness, material allowable stress, service temperature and the applicable piping design code.
| Rating Input | Governing Reference |
|---|---|
| Allowable stress at temperature | ASME B31.3, Appendix A, Table A-1 (process piping) |
| Pipe dimensions and schedules | ASME B36.19M / applicable B36.10M requirements |
| Piping design | ASME B31.3 |
| Material testing | ASTM A790 / applicable ASTM requirements |
The final allowable pressure should therefore be established through the project design calculation rather than inferred from the pipe schedule alone.
Duplex S31803 is available in several construction and product forms depending on the application and required specification.
Contact us to receive a firm duplex stainless steel pipe price quotation, calculated precisely according to your requested technical specifications, volume, and current alloy surcharges.
Request a QuoteDuplex steel pipes and tubes are supplied in strapped bundles with suitable end protection. Custom cut lengths can be packed in timber cases or other suitable export packaging. Each length or bundle is identified with the applicable grade, size, specification and heat number for material traceability.
Amigo Impex dispatches duplex steel pipes and tubes across India from Mumbai and handles export consignments to international markets. Stock requirements can be dispatched according to availability, while made-to-order material is supplied against the confirmed production schedule.
Each Duplex S31803 consignment from Amigo Impex is supplied with a comprehensive mill test certificate ensuring strict heat-number traceability, material identification, chemical analysis, and mechanical test results aligned with governing specifications. Operating under AS 9120B, ISO 9001:2015, and ISO 45001:2018 certifications, our company supports project-specific documentation and conducts rigorous testing and inspection services including chemical analysis, tensile and mechanical testing, hydrostatic testing, non-destructive examination, Positive Material Identification (PMI), and independent third-party inspections upon request.
60–70 tonnes held in Mumbai, with urgent requirements dispatched within one to two days.
AS 9120B, PED, ISO 9001:2015 and ISO 45001:2018, with an MTC on every order.
Cutting, machining, threading, fabrication and testing all handled at our own Mumbai facility.
Original mill certificates plus our own test reports, so every batch can be traced back.
Non-standard sizes and specifications made to order.
Dispatched from Mumbai to every major Indian city, and exported to USA, Gulf, Europe, Asia
Duplex steel pipe is generally specified by nominal pipe size (NPS/NB) and schedule for fluid-handling systems, while duplex steel tube is normally ordered by exact outside diameter (OD) and wall thickness. Tubes are commonly used in heat exchangers, condensers and instrumentation applications.
Amigo Impex supplies Duplex S31803 / Duplex 2205 pipes and tubes. The standard supply range focuses on UNS S31803.
ASTM A790 / ASME SA-790 covers seamless and welded ferritic/austenitic stainless steel pipe, including Duplex S31803 pipe. Duplex tubing is covered by ASTM A789 / ASME SA-789.
Yes, Duplex S31803 pipe can be welded using qualified procedures. Heat input, interpass temperature, filler selection (such as ER2209) and welding procedure controls are essential to maintain the correct ferrite-austenite phase balance and preserve corrosion resistance in the weld and heat-affected zones.
Yes, Duplex S31803 consignments are supplied with EN 10204 3.1 mill test certificates containing full chemical analysis, mechanical test results and heat-number traceability. 3.2 inspection can also be arranged on request.
Duplex Steel pipes and tubes are used in industries where corrosion resistance or high specific strength is important. Major application sectors include:
