Duplex Fasteners

Duplex Fasteners are high-strength corrosion-resistant fastening solutions manufactured from duplex stainless steel alloys that combine the advantages of both austenitic and ferritic stainless steels. Known for their exceptional mechanical strength, resistance to stress corrosion cracking, and superior performance in aggressive environments, duplex fasteners are widely used in offshore, marine, oil & gas, chemical processing, and heavy industrial applications.

At The Industrial Mandate, we supply a comprehensive range of duplex stainless steel fasteners including bolts, nuts, socket screws, washers, threaded rods, and custom fastening solutions manufactured to international standards for critical industrial environments.

What are Duplex Fasteners?

Duplex fasteners are fastening components manufactured from duplex stainless steel grades featuring a dual-phase microstructure of approximately equal parts austenite and ferrite. This unique metallurgical structure provides a combination of high strength, toughness, and excellent corrosion resistance not typically achieved with conventional stainless steels.

Duplex stainless steels are commonly used where applications require:

  • High mechanical strength
  • Resistance to chloride corrosion
  • Superior pitting and crevice corrosion resistance
  • Excellent fatigue performance
  • Long service life in harsh environments

Compared to standard 304 and 316 stainless steel fasteners, duplex fasteners offer significantly higher yield strength and improved resistance to stress corrosion cracking.

Types of Duplex Fasteners

We supply a complete range of duplex stainless steel fastening products including:

  • Duplex Bolts
  • Duplex Nuts
  • Duplex Socket Screws
  • Duplex Washers
  • Duplex Stud Bolts
  • Duplex Threaded Rods
  • Duplex U Bolts
  • Duplex Machine Screws
  • Duplex Hex Head Bolts

These fasteners are available in both metric and imperial sizes with coarse and fine thread options suitable for industrial and engineering applications.

Common Duplex Stainless Steel Grades

Duplex 2205 Fasteners

Duplex 2205 (UNS S32205 / S31803) is the most widely used duplex stainless steel grade, offering excellent strength and corrosion resistance for industrial applications.

Super Duplex 2507 Fasteners

Super Duplex 2507 (UNS S32750) provides even greater corrosion resistance and strength, particularly in chloride-rich and offshore environments.

Zeron 100 Fasteners

Zeron 100 is a high-alloy super duplex grade designed for extremely aggressive process environments requiring exceptional corrosion resistance.

Properties of Duplex Fasteners

High Mechanical Strength

Duplex stainless steel fasteners offer approximately twice the yield strength of conventional 300 series stainless steels such as 304 and 316.

Excellent Corrosion Resistance

These fasteners provide outstanding resistance to:

  • Pitting corrosion
  • Crevice corrosion
  • Chloride stress corrosion cracking
  • General corrosion in aggressive environments

This makes duplex fasteners highly suitable for marine and chemical processing applications.

Superior Fatigue and Erosion Resistance

Duplex alloys maintain strong mechanical integrity under cyclic loading and abrasive industrial environments.

Cost-Effective Performance

Duplex stainless steel often provides a more economical alternative to nickel alloys and titanium while delivering excellent corrosion resistance and strength.

Standards and Specifications

Duplex fasteners are manufactured according to internationally recognised standards including:

  • ASTM A182
  • ASTM A276
  • ASTM A479
  • ASTM A815
  • ASTM A1082
  • DIN Standards
  • ISO Standards
  • BS Standards

These specifications define mechanical properties, dimensional tolerances, chemical composition, and performance requirements for industrial fasteners.

Applications of Duplex Fasteners

Duplex fasteners are widely used across industries where corrosion resistance and high strength are critical:

  • Offshore Oil & Gas Platforms
  • Petrochemical Plants
  • Marine & Shipbuilding
  • Chemical Processing Facilities
  • Desalination Plants
  • Power Generation
  • Structural Engineering
  • Water Treatment Systems
  • Pulp & Paper Industry

Their superior resistance to chloride environments makes duplex fasteners ideal for coastal and offshore applications.

Why Choose The Industrial Mandate for Duplex Fasteners?

  • Extensive range of duplex and super duplex grades
  • Manufactured to international standards
  • High strength and corrosion resistant materials
  • Suitable for offshore and industrial applications
  • Metric and imperial sizes available
  • Reliable global supply capability

At The Industrial Mandate, we provide premium quality duplex fasteners engineered for durability, strength, and long-term reliability in demanding industrial environments.