Duplex/Super Duplex Pipes
- PRODUCT DETAIL
Duplex stainless steel pipe
DESCRIPTION
The differences between duplex/super duplex pipes:
WHAT IS DUPLEX STEEL?
Duplex stainless steel (UNS S31803/UNS S32205) has been developed to overcome the issues of the 300 series stainless steels, it has stronger resistance to seawater corrosion compared to stainless steel 316.
Note that, despite Duplex stainless steel shows good high-temperature oxidation resistance, 2205 suffers from embrittlement if kept at temperatures above 300ºC for some period of time. (a situation that can be rectified only by a full solution annealing treatment). For this reason, Duplex stainless steels are never used for temperatures in excess of 300ºC.
UNS2205 duplex steel finds application in marine projects, oil & gas exploration, closed loops water systems, desalinization plants, hydrocarbons storage and transportation, downstream refining, pulp, and paper.
WHAT IS SUPER DUPLEX?
Super duplex stainless steel is a variation of the duplex steel alloy which is used in the oil & gas, chemical, power generation, mechanical and desalination industries. The higher chromium and molybdenum content of Super Duplex compare to Duplex makes it extremely resistant to uniform corrosion by organic acids like formic and acetic acid. Super Duplex also provides excellent resistance to inorganic acids, especially those containing chlorides.
Duplex steel Pipe & Tube Chemical Composition:
| Grade | C≤ | Mn≤ | P≤ | S≤ | Si≤ | Ni | Cr | Mo | N | Cu |
| S31803 | 0.03 | 2.00 | 0.03 | 0.02 | 1.00 | 4.5–6.5 | 21.0–23.0 | 2.5–3.5 | 0.08–0.20 | – |
| S32205 | 0.03 | 2.00 | 0.03 | 0.02 | 1.00 | 4.5–6.5 | 22.0–23.0 | 3.0–3.5 | 0.14–0.20 | – |
| S32750 | 0.03 | 1.20 | 0.035 | 0.02 | 0.80 | 6.0-8.0 | 24.0-26.0 | 3.0-5.0 | 0.24-0.32 | 0.5 |
| S32760 | 0.05 | 1.00 | 0.03 | 0.01 | 1.00 | 6.0-8.0 | 24.0-26.0 | 3.0-4.0 | 0.20-0.30 | 0.50–1.00 |
Duplex steel Pipe & Tube Mechanical Properties:
| Mechanical properties | Tensile,min,ksi[MPa] | Yield,min,ksi[MPa] | Elongation,%(min) | Hardness,HB(max) |
| S31803 | 90 [620] | 65 [450] | 25 | 290 |
| S32205 | 95 [655] | 65 [450] | 25 | 290 |
| S32750 | 116 [800] | 80 [550] | 15 | 300 |
| S32760 | 109 [750] | 80 [550] | 25 | 300 |
Specifications / Standards
Duplex stainless steel pipes and tubes can be supplied according to international standards and project specifications.
Typical standards include:
ASME SA789 / ASTM A789
ASME SA790 / ASTM A790
ASTM A928
EN standards where applicable
NACE MR0175 / ISO 15156 where required
Project specifications and customer drawings
Materials can be supplied with EN 10204 Type 3.1 or 3.2 certification.
Material Grades
Typical duplex and super duplex grades include:
UNS S31803
UNS S32205 (Duplex 2205)
UNS S32750 (Super Duplex 2507)
UNS S32760 (Super Duplex)
Duplex stainless steels provide higher strength than austenitic stainless steels and excellent resistance to pitting corrosion and stress corrosion cracking.
Size Range
Duplex stainless steel pipes and tubes can be supplied in various sizes and dimensions including:
Outside diameter from 1/2” to 48”
Wall thickness according to ASME B36.19 / B36.10
Seamless and welded pipes
Random length or fixed length
Cut-to-length and machining available
Supply dimensions can be adjusted according to project requirements.
Manufacturing Process
Manufacturing processes may include:
Seamless pipe production
Welded pipe production
Cold drawing
Heat treatment
Pickling and surface finishing
Cutting and beveling
All materials are manufactured according to applicable standards and project technical specifications.
Inspection & Testing
Inspection and testing may include:
PMI testing
Hydrostatic testing
Ultrasonic testing
Mechanical testing
Hardness testing
Chemical composition analysis
Third-party inspection
All materials can be supplied with quality control and inspection documentation including EN10204 certification and inspection reports.
Applications / Industries
Duplex stainless steel pipe is widely used as piping materials for industrial projects including:
Offshore platforms
Oil and gas pipelines
Petrochemical plants
Desalination plants
Power plants
Marine projects
Industrial piping systems
Duplex stainless steel is selected where high strength and corrosion resistance are required in aggressive environments.
Packaging & Delivery
Materials are packed to ensure protection during transportation and storage.
Typical packaging includes:
Bundles with steel straps
Wooden cases
Wooden pallets
Waterproof wrapping
End caps
Export seaworthy packing
Marking according to project requirements
Delivery can be arranged by container shipment or project cargo shipment.
Why Choose Us
We supply duplex stainless steel pipes and tubes for engineering and industrial projects worldwide.
Our services include:
Material sourcing and supply
Project material supply coordination
Inspection and documentation support
Third-party inspection coordination
Supply for both small quantity and large project orders
Material traceability and documentation
Supply chain support for industrial projects
We support customers not only as a supplier, but as a supply chain partner supporting industrial projects from material sourcing to final delivery.