Duplex and Super Duplex Fasteners: Robust Solutions for High-Performance Applications

Duplex and super duplex fasteners are specifically engineered to combine the strength of ferritic and austenitic steels, offering exceptional resistance to corrosion and high strength, making them ideal for demanding environments. These fasteners are widely used in industries such as oil and gas, marine, and chemical processing, where standard materials might not withstand harsh conditions.

Types of Duplex/Super Duplex Fasteners

Duplex and super duplex fasteners are available in a wide range of forms, tailored for different fastening applications:

• Bolts: These fasteners feature external threads and are used to secure objects together. Some of the popular types include:

  • Stud Bolts: Threaded rods used with nuts to fasten materials.

  • Hex Head Bolts: Commonly used bolts with a hexagonal head that can be tightened using a wrench.

  • Socket Hexagon Head Screws: Screws driven by a hexagonal socket tool, offering a compact design.

  • Anchor Bolts: Designed for securing structures to concrete or other materials.

  • U-Bolts: Shaped like a “U” to secure pipes, rods, or cables.

  • J-Bolts: Similar to U-bolts but shaped in the form of the letter “J,” providing a secure attachment to surfaces.

  • Mushroom Head Square Neck Bolts: Bolts with a square neck that prevents them from rotating during installation.

  • T-Head Bolts: Bolts with a T-shaped head, widely used in machinery and structural applications.

  • Wing Screws: Screws with “wings” that allow manual tightening without the use of tools.

Sizes of Duplex/Super Duplex Fasteners

Duplex and super duplex fasteners are available in various sizes, allowing for flexibility in different projects:

• Metric Sizes: M3 – M56

• Inch Sizes: 3/6 Inch to 2 Inch

This extensive range ensures that fasteners can be selected according to the specific requirements of any given application, from small-scale installations to large industrial projects.

Grades of Duplex/Super Duplex Fasteners

The performance and resistance of duplex and super duplex fasteners are determined by their specific grades. These fasteners provide outstanding mechanical properties and resistance to corrosion in both oxidizing and reducing environments. Common grades include:

• UNS S31803 (F51): This duplex stainless steel is widely used due to its excellent resistance to stress corrosion cracking and general corrosion, making it ideal for the chemical and petrochemical industries.

• UNS S2205 (F60): A more commonly used duplex stainless steel with a higher resistance to corrosion, pitting, and crevice corrosion. It is used in applications such as desalination plants and offshore environments.

• UNS S32750 (F53): This super duplex stainless steel offers superior resistance to pitting and crevice corrosion in seawater and other chloride environments. It’s ideal for industries such as oil and gas and marine.

• UNS S32760 (F55): Known for its high resistance to corrosion, particularly in harsh environments, this grade is often used in the chemical, marine, and power industries for critical components.

Key Highlights

• Corrosion Resistance: Duplex and super duplex fasteners offer exceptional resistance to corrosion, including pitting and crevice corrosion, making them ideal for use in aggressive environments like offshore and chemical industries.

• Strength & Durability: These fasteners are designed for high strength and durability, offering robust performance even under extreme conditions such as high pressure, temperature, and aggressive chemicals.

• Versatility: Available in a range of sizes, types, and grades, duplex and super duplex fasteners can be used in a variety of industrial applications, from oil rigs to desalination plants.

• Cost-Effective: Despite their high performance, duplex and super duplex alloys often offer a more cost-effective alternative to pure nickel or other superalloys in many applications.

Duplex and super duplex fasteners provide the ideal solution for industries that require both high strength and excellent corrosion resistance. With their exceptional mechanical properties, they ensure reliability and long-lasting performance in even the most demanding environments.