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Duplex / Super Duplex Fasteners and Components

Energy Bolting supply fasteners and machined components in Duplex & Super Duplex grade materials

Special Screws with left hand thread supplied by Energy Bolting in UNS S32760 Super Duplex Material

The first cast of duplex was produced in Sweden during the 1930's, it is now commonly used within - chemical processing, oil and gas exploration, offshore rigs, heat exchangers, boilers, and pressure vessels.


Duplex stainless steels have a two-phase structure consisting of almost equal parts of austenite and ferrite. They have become very popular because they are approximately twice as strong as common austenitic stainless steels but less expensive, owing to the lower levels of nickel they contain.

Duplex stainless steels offer excellent resistant to corrosion and very high mechanical strength, this high corrosion resistance ensures significantly more uptime than carbon steels and ''conventional'' stainless steels.

Super Duplex stainless steel has all of the same benefits as its counterpart, the main difference being that this metal has a higher chromium and molybdenum content, which provides it with increased corrosion resistance.

Summary of Duplex Characteristics

  • Twice the design strength of austenitic and ferritic stainless steels.

  • Wide range of corrosion resistance to match application.

  • Toughness and ductility.

  • Particular resistance to stress corrosion cracking, this can be seen in the PREN (pitting resistance equivalent number) of duplex stainless steel as well as in its tensile strength.

Strength, toughness, corrosion resistance and resistance to stress corrosion cracking) are achieved when there is at least 25% ferrite, with the balance being austenite.


Energy Bolting supply fasteners / bolting, machined components and associated products in the below material designations.

Duplex UNS S31803 Duplex 2205, Werkstoff 1.4462, ASTM A182 F51, ASTM A276, ASTM A479

Super Duplex UNS S32550


Super Duplex UNS S32750

UNS S32750, Alloy 2507, Werkstoff 1.4410, A182 F53, ASTM A479, ASTM A473

Super Duplex UNS S32760

Werkstoff 1.4501, ASTM A182 F55, S32760 SA, S32760 FLT, S32760 FG, ASTM A276 Condition A, ASTM A276 Condition S, Zeron 100 SA ®, Zeron 100 FLT ®, X2CrNiMoCuWN25.7.4

Products include: Studbolts, Hexnuts, Washers, Hexagon Bolts, Hexagon Setscrews, Socket Head Capscrews, 12pt Bi-Hexagonal Bolt & Nuts, Ring Joint Gaskets

Client specific requirements to drawing and specification

Energy Bolting specialise in the bespoke production of Duplex & Super Duplex grade components.

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Data contained is for information purposes only and may be revised at any time.

Energy Bolting Limited makes no recommendation or warranty of any kind and assumes no liability with respect to the accuracy of the information contained herein.


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