Precision-Engineered Super Duplex Hex Nuts

Super Duplex Information, Composition & Properties

Super Duplex stainless steels are high-performance alloys engineered to provide a superior combination of high mechanical strength and exceptional corrosion resistance. Characterised by a dual-phase microstructure consisting of approximately equal parts austenite and ferrite, these alloys offer significantly better performance than standard 300-series stainless steels. This balanced structure makes Super Duplex an ideal material for hex nuts used in critical assemblies, as it provides the toughness and ductility required for secure fastening alongside the rigidity needed to maintain structural integrity under load.

Composition:
The exceptional properties of Super Duplex are derived from its precise chemical composition, typically featuring high levels of chromium (24-28%), molybdenum (3-5%), and nitrogen (0.2-0.35%). These elements work synergistically to provide a high Pitting Resistance Equivalent Number (PREN), usually exceeding 40. Nickel (6-8%) is also included to stabilize the austenitic phase, while some grades, such as UNS S32760, include additions of tungsten and copper to further enhance resistance to specific acids and crevice corrosion.

Properties:

• Excellent Corrosion Resistance: Super Duplex hex nuts offer outstanding resistance to pitting and crevice corrosion in chloride-rich environments, making them indispensable for marine and offshore applications.
• High Tensile and Yield Strength: With a yield strength approximately double that of standard austenitic stainless steels, these nuts allow for more compact and lightweight fastener designs without sacrificing safety.
• Stress Corrosion Cracking Resistance: The ferritic component of the microstructure provides excellent resistance to chloride-induced stress corrosion cracking, a common failure mode in traditional stainless fasteners.
• Fatigue and Erosion Resistance: The inherent hardness and strength of the material ensure long-term durability in high-vibration or abrasive environments, such as chemical processing and subsea systems.

At West Special Fasteners, we take pride in every Super Duplex Hex Nut we produce, no matter the application.

99% on-time delivery

At West Special Fasteners, we deliver precision-engineered fasteners with a proven 99% on-time delivery record, ensuring your projects stay on schedule. With lead times as short as 4 weeks for full-service orders, we provide unmatched reliability for industries where timing is critical.

• Minimise delays – Receive your special fasteners exactly when needed, helping you avoid costly project interruptions.
• Support critical operations – Our dependable delivery is essential for sectors like defence, offshore, and renewables, where timing is non-negotiable.
• Boost project efficiency – Reliable deliveries streamline your workflow, allowing you to focus on execution without supply chain concerns.
• Maintain your reputation – Trust in our punctuality to ensure your commitments to your clients are met, every time.
• Transparent communication – Realistic timelines and proactive updates at every stage.
• Efficient production – Our advanced facilities and streamlined processes enable us to deliver on time, even for complex and bespoke projects.

Our ability to always deliver on time sets us apart in the fastener industry. While with many competitors you can face frequent delays, we ensure your orders are delivered with precision and professionalism – backed by our fully traceable production process and industry-leading expertise.