Overview

Key Parameters

• Alloy Grade: UNS S32760 (also known as 2507-Plus or Zeron® 100, a super duplex alloy with high chromium, molybdenum, and nitrogen content).
• Chemical Composition (Typical, %):
  • Chromium (Cr): 24.0 - 26.0 (enhances oxidation and general corrosion resistance).
  • Nickel (Ni): 6.0 - 8.0 (stabilizes the austenitic phase, improving toughness and ductility).
  • Molybdenum (Mo): 3.0 - 4.0 (boosts resistance to pitting and crevice corrosion, especially in chloride-rich environments).
  • Nitrogen (N): 0.20 - 0.30 (strengthens the alloy, enhances pitting resistance, and stabilizes the duplex structure).
  • Iron (Fe): Balance.
  • Other elements: Carbon (C) ≤ 0.03, Silicon (Si) ≤ 1.0, Manganese (Mn) ≤ 1.0, Copper (Cu) 0.5 - 1.0, Tungsten (W) 0.5 - 1.0 (improves corrosion resistance in harsh media).
• Mechanical Properties:
  • Tensile Strength: ≥ 800 MPa.
  • Yield Strength: ≥ 550 MPa (significantly higher than austenitic stainless steels like 316).
  • Elongation: ≥ 25% (good ductility for forming and welding).
  • Hardness: ≤ 31 HRC.
  • Corrosion Resistance: Excellent pitting resistance equivalent (PREN ≥ 40), resistant to chloride-induced stress corrosion cracking (SCC), pitting, and crevice corrosion.

Standards

• ASTM A790/A790M (Standard Specification for Seamless and Welded Ferritic/Austenitic Duplex Stainless Steel Pipe).
• ASTM A928/A928M (Standard Specification for Welded Ferritic/Austenitic Duplex Stainless Steel Tube for General Service).
• ASME SA790 (Code for pressure vessel and piping applications, widely used in energy and chemical industries).
• EN 10217-7 (European standard for welded stainless steel tubes for pressure purposes, applicable to super duplex grades).

Specifications

• Form: Hollow pipe/tubing (available in seamless or welded variants, depending on application requirements).
• Schedule: SCH40S (a standard wall thickness designation for stainless steel pipes, balancing strength and weight for medium to high-pressure systems).
• Length: 6m (standard length, customizable to shorter lengths upon request for specific project needs).
• Outer Diameter (OD): Typically ranges from 1/2 inch (12.7mm) to 12 inches (304.8mm) (covers a broad spectrum of industrial piping requirements).
• Wall Thickness: Conforms to SCH40S standards (varies with OD; e.g., 0.154 inches for 2-inch OD, 0.216 inches for 4-inch OD).
• Surface Finish: Generally pickled and passivated (removes scale, improves corrosion resistance, and provides a clean, uniform surface).

Similar Grades

• UNS S32750 (2507): A widely used super duplex grade with slightly lower tungsten and copper content, offering similar corrosion resistance and strength.
• UNS S32550 (Ferralium 255): Combines high chromium, molybdenum, and nickel for resistance to acidic and chloride environments, with marginally lower tensile strength than S32760.
• UNS S32900: A duplex grade (not "super") with lower molybdenum and nitrogen, suitable for less aggressive environments.
• EN 1.4501: European equivalent to S32760, with matching chemical composition and mechanical properties.

Applications

• Oil and Gas Industry: Offshore and onshore pipelines, risers, and wellhead equipment, where resistance to seawater, sour gas (H₂S), and high pressure is critical.
• Chemical Processing: Piping for handling acids (e.g., sulfuric acid, hydrochloric acid), chlorides, and aggressive chemicals, as well as reactors and heat exchangers.
• Desalination Plants: Systems for seawater intake, reverse osmosis, and brine handling, where chloride-induced corrosion is a major concern.
• Marine Engineering: Hull components, ballast tanks, and offshore platforms, resisting saltwater corrosion and biofouling.
• Power Generation: Flue gas desulfurization (FGD) systems, cooling water pipes, and wastewater treatment lines in fossil fuel and nuclear power plants.
• Pulp and Paper Industry: Digester piping and bleaching systems, withstanding harsh chemicals like chlorine dioxide.