Duplex Stainless Steel Seamless Pipes (UNS S31803 / S32205) – High-Strength, Corrosion-Resistant Solutions

Product Overview

Duplex Stainless Steel Seamless Pipes (UNS S31803 / S32205) are high-performance alloy pipes engineered with a balanced austenitic-ferritic (50/50) microstructure, delivering an optimal combination of high mechanical strength, excellent corrosion resistance, and long-term durability.

Compared to conventional austenitic stainless steels such as 304L and 316L, duplex pipes offer:

  • Up to 2× higher yield strength
  • Improved resistance to chloride environments
  • Reduced wall thickness and overall system weight

These advantages make duplex seamless pipes an ideal solution for high-pressure, corrosive, and safety-critical applications.

Key Features & Technical Advantages

1. Superior Corrosion Resistance (High PREN Value)

With elevated levels of Chromium (Cr), Molybdenum (Mo), and Nitrogen (N), duplex stainless steel pipes achieve a high Pitting Resistance Equivalent Number (PREN), ensuring outstanding performance in aggressive environments.

Performance Highlights:

  • Excellent resistance to pitting and crevice corrosion
  • Superior protection in chloride-rich and marine environments
  • High resistance to Chloride Stress Corrosion Cracking (SCC)

2. High Mechanical Strength & Structural Integrity

Duplex S31803 / S32205 seamless pipes provide:

  • Nearly double the yield strength of 300-series stainless steel
  • High toughness at sub-zero temperatures
  • Stable performance up to 300°C (572°F)

Engineering Benefits:

  • Reduced material consumption
  • Lower installation and transportation costs
  • Enhanced safety in high-pressure systems

3. Compliance with International Standards

Our duplex stainless steel seamless pipes are produced in full compliance with global standards:

  • ASTM A790 / ASTM A789
  • ASME SA790 / SA789
  • EN standards available upon request

Quality Control:

  • 100% Non-Destructive Testing (NDT)
    • Ultrasonic Testing (UT)
    • Eddy Current Testing (ECT)
    • Hydrostatic Testing
  • Full traceability with Mill Test Certificates (EN 10204 3.1)

Industrial Applications

Due to their excellent combination of strength, corrosion resistance, and durability, duplex seamless pipes are widely used in:

Oil & Gas Industry

  • Offshore platforms and subsea pipelines
  • Sour gas environments (H₂S service)
  • Flowlines and risers

Chemical & Petrochemical Processing

  • Heat exchangers and pressure vessels
  • Transport systems for acids, alkalis, and chlorides

Marine & Desalination

  • Seawater cooling systems
  • Reverse osmosis (RO) plants
  • Desalination pipelines

Power Generation

  • Flue Gas Desulfurization (FGD) systems
  • Nuclear and thermal power cooling circuits

Product Range & Customization

We offer a full range of duplex stainless steel seamless pipes tailored to your project requirements:

  • Outer Diameter (OD): Custom sizes available
  • Wall Thickness (WT): Wide range options
  • Schedules: SCH 10S, 40S, 80S, 160, XXS
  • Surface Finish:
    • Annealed & Pickled (AP)
  • Bright Annealed (BA)

    • Packaging, Certification & Delivery

    • Export-grade packaging for global shipping
    • Complete documentation package
    • Fast delivery for urgent project timelines
    • Compliance with international logistics standards

    Why Choose Us as Your Duplex Pipe Supplier?

    • Specialized in Duplex & Super Duplex stainless steel pipes
    • Extensive export experience across global markets
    • Competitive pricing with stable supply chain
    • Technical support for material selection and engineering optimization
    • Reliable quality with strict inspection protocols