Product Overview
Duplex Steel Seamless Pipe features a precisely balanced dual-phase microstructure composed of 50% austenite and 50% ferrite. This metallurgical design combines high mechanical strength with exceptional corrosion resistance. Manufactured through advanced seamless extrusion and cold-drawing processes, these pipes deliver uniform wall thickness, structural integrity, and reliable pressure containment under continuous long-term service in severe chemical, process, and marine environments.
Technical Specifications
|
Parameter |
Specification Details |
|
Outer Diameter (OD) |
6 mm – 711 mm (1/8" to 28" NPS) |
|
Wall Thickness (WT) |
0.5 mm – 50 mm (Sch 5S to Sch XXS) |
|
Length |
Single Random, Double Random, 1m to 12m, or precise cut-to-length |
|
Material Grades |
UNS S31803, UNS S32205, UNS S32750, UNS S32760 |
|
Manufacturing Process |
Cold Drawn, Cold Rolled, Hot Finished |
|
Surface Finish |
Solution Annealed & Pickled (SAP), Bright Annealed (BA), Polished |
|
Pipe Ends |
Plain End (PE), Beveled End (BE) to ASME B16.25, Threaded |
|
Quality Testing |
Mechanical (Tensile, Hardness, Flattening), Chemical, Ferrite Count, Corrosion (ASTM G48) |
Key Advantages
Higher allowable design stress enables thinner wall configurations, reducing total material weight and freight expenses.
High alloy stability ensures prolonged service life in severe operational environments.
Premium structural reliability minimizes maintenance requirements and supports continuous operation.
Low coefficient of thermal expansion ensures dimensional stability during temperature fluctuations.
Material Grades & Standards
|
Duplex Stainless Steel Grades |
UNS S31803, UNS S32205, F51, F60 |
|
Super Duplex Stainless Steel Grades |
UNS S32750, UNS S32760, F53, F55, Alloy 2507 |
|
Manufacturing Standards |
ASTM A790, ASME SA790, EN 10216-5, NACE MR0175 / ISO 15156 |
Manufacturing Process & Quality Control
A rigorous, fully traceable quality assurance framework governs every stage of production:
Refining: Vacuum Induction Melting (VIM) and Argon Oxygen Decarburization (AOD) for exact chemical composition control.
Forming: Hot extrusion and precision cold drawing to achieve specified geometric tolerances.
Heat Treatment: Solution annealing followed by water quenching to optimize the 50:50 phase balance.
Non-Destructive Testing (NDT): 100% Ultrasonic Testing (UT) and Eddy Current Testing (ET) to ensure zero internal and surface imperfections.
Pressure & Verification Testing: Hydrostatic testing calibrated to maximum design pressure limits, alongside Positive Material Identification (PMI), ferrite count validation, and mechanical testing (Tensile, Hardness, Flattening).
Industrial Applications
Offshore Oil & Gas: Subsea flowlines, manifolds, riser systems, and topside process piping.
Desalination & Water Treatment: High-pressure reverse osmosis (RO) piping and seawater intake systems.
Chemical Processing: Production systems handling organic acids, chloride-bearing solutions, and aggressive industrial fluids.
Marine Engineering: Coastal infrastructure, marine scrubbing units, and cargo piping systems.
Power Generation: Flue gas desulfurization (FGD) systems and heavy-duty cooling water circuits.
Customization & Processing Options
Precision Tolerances
Tailored dimensional configurations to meet specific engineering alignments.
End Preparation
Custom beveling angles and face preparation optimized for automated field welding.
Advanced Inspection Protocols
Low-temperature impact testing, extended corrosion testing (ASTM G48), and third-party inspection (TPI) support.
Compliance Certifications
Manufacturing facilities operate under strict international quality management systems:
- ISO 9001, ISO 14001, and ISO 45001 certification.
- PED (Pressure Equipment Directive) compliance for pressure systems.
- Major Classification Society Approvals (ABS, DNV, LR, BV).
- Material Test Certificates (MTC) issued in accordance with EN 10204 3.1 and EN 10204 3.2.
Packaging & Delivery
- Hexagonal bundling with steel straps or individual packing in seaworthy wooden cases.
- Heavy-duty plastic end caps to protect the pipe interior and beveled edges from contamination.
- Waterproof synthetic wrapping to protect against maritime humidity during transport.
- Standard export-compliant container loading (20ft / 40ft) or bulk shipment coordination.
Frequently Asked Questions
Q: What are the primary structural benefits of the 50:50 duplex phase balance?
A: The balanced microstructure combines the high mechanical strength of ferrite with the excellent corrosion resistance of austenite. This results in twice the yield strength of standard stainless steel and exceptional resistance to stress corrosion cracking.
Q: Can super duplex seamless pipes be utilized in high-salinity environments?
A: Yes. Super duplex grades such as UNS S32750 and S32760 contain elevated levels of chromium, molybdenum, and nitrogen. Achieving a PREN >= 40, they are specifically designed for warm seawater and high-chloride applications.
Q: What documentation is provided to guarantee material authenticity?
A: All shipments include an EN 10204 3.1 or 3.2 Material Test Certificate (MTC) detailing the specific heat number, chemical composition analysis, mechanical test results, ferrite counts, and non-destructive test reports.
Q: Are custom sizes, lengths, and specific tolerances available for project orders?
A: Yes. Production schedules accommodate customized outer diameters, specific wall thicknesses, fixed-cut lengths, and tight geometric tolerances to match exact engineering specifications.
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