ASTM A790 S32550 Duplex Stainless Steel Pipe Tube Pickling and Bright Finishing

ASTM A790 S32550 Duplex Stainless Steel Pipe Tube Pickling and Bright Finishing

Products Specification

Chemical Composition

• Chromium (Cr): 24.0–27.0%
• Nickel (Ni): 4.5–6.5%
• Molybdenum (Mo): 2.9–3.9%
• Copper (Cu): 1.5–2.5%
• Nitrogen (N): 0.10–0.25%
• Carbon (C): ≤0.04%
• Other: Mn ≤1.5%, Si ≤1.0%, P ≤0.04%, S ≤0.03%

Mechanical Properties

• Tensile Strength: ≥750 MPa (110 ksi)
• Yield Strength (0.2% offset): ≥500 MPa (72.5 ksi)
• Elongation: ≥15%
• Hardness: 250–330 HB
• Impact Resistance: ≥60 J at -46°C

Physical Properties

• Density: 7.85 g/cm³
• Thermal Conductivity: 15.1–23.3 W/m·K (varies with temperature)
• Thermal Expansion Coefficient: 12.3×10⁻⁶/K (100–500°C)
• Resistivity: 850 nΩ·m
• Melting Point: 1390–1440°C

Performance

1. Corrosion Resistance
   • Pitting/Crevice Corrosion: Critical pitting temperature (CPT) ≥55°C (ASTM G48) .
   • Stress Corrosion Cracking (SCC): Exceptional resistance in chloride-rich environments, outperforming 316L by 5–10 times .
   • Acid Resistance: Resistant to sulfuric, phosphoric, and nitric acids, with low corrosion rates (e.g., 0.15 mm/year in 10% FeCl₃ + 3% HCl at 40°C) .
2. Mechanical Strength
   • High tensile strength (≈3× that of 316L) enables lighter structural designs without compromising safety .
   • Retains ductility and toughness even at sub-zero temperatures (-50°C) .
3. Weldability
   • Compatible with GTAW, SMAW, and SAW processes using ER2594 filler metal. Post-weld heat treatment (1020–1100°C water quench) optimizes phase balance .
4. Surface Finish
   • Pickling & Bright Finishing: Removes mill scale and oxides, enhancing corrosion resistance and aesthetic appeal. Bright finishes (e.g., 2B, BA) are ideal for hygienic applications .

Specifications

• Dimensions:
  • OD: 6–762 mm (0.25–30 inches)
  • Wall Thickness: 0.5–35 mm (0.02–1.38 inches)
  • Length: Customizable (typically 3–12 meters)
• Manufacturing Methods:
  • Seamless: Produced via hot extrusion or cold drawing.
  • Welded: ERW or seamless-welded with 100% NDT (e.g., ultrasonic testing per ASTM E213) .
• Standards Compliance:
  • ASTM A790/A790M, ASME SA-790, EN 10216-5, and NACE MR0175 .

Applications

1. Marine & Offshore:
   • Seawater desalination systems, subsea pipelines, and offshore platform components.
   • Replaces titanium in RO membrane housings, reducing costs by 30% .
2. Oil & Gas:
   • Downhole tubing, wellheads, and H₂S-resistant equipment (up to 5000 ppm H₂S) .
3. Chemical Processing:
   • Reactors, heat exchangers, and pipelines handling aggressive chemicals (e.g., 60% H₃PO₄) .
4. Mining & Pulp/Paper:
   • Slurry transport pipes, digesters, and bleach plants due to high abrasion resistance .
5. Power Generation:
   • Flue gas desulfurization (FGD) systems and condenser tubes in coal-fired plants .

Export Packaging

• Primary Packaging:
  • Wooden Crates/Pallets: Treated per ISPM-15 standards (heat-treated or fumigated) with IPPC markings .
  • Plastic Sheeting: Encapsulates pipes to prevent moisture and mechanical damage.
  • Steel Strapping: Secures bundles for stability during transit.
• Secondary Protection:
  • Anti-Corrosive Coatings: Optional wax or oil-based coatings for long-term storage.
  • Marking: Product specifications (grade, size, batch), ISO shipping labels, and handling instructions.
• Documentation:
  • Certificate of Conformance (CoC) with chemical/mechanical test results.
  • Material Test Reports (MTRs) compliant with EN 10204 3.1B.

Standards & Compliance

• ASTM A790/A790M: Primary specification for seamless/welded duplex stainless steel pipes .
• ASME SA-790: For pressure-containing applications in boilers and pipelines.
• EN 1.4507: European equivalent standard for S32550 .
• NACE MR0175: Compliant for sour gas environments.