Super Duplex Stainless Steel

Super Duplex Products

Stress Corrosion Cracking within Marine Grade stainless steel

Duplex stainless steels are becoming more common. They are being offered by all the major stainless steel mills for a number of reasons:

  • Higher strength leading to weight saving
  • Greater corrosion resistance particularly stress corrosion cracking

Summary of Duplex Characteristics

Characteristic Benefit
High inherent corrosion resistance No need to protect by surface coating
Outstanding pitting/crevice resistance Ideal for oil & gas, marine & defence applications
Excellent corrosion resistance in acids Ideal for chemical industry
High resistance to stress corrosion cracking Suitable for highly loaded components in chloride environments
High resistance to chloramines at high temperature / humidity Suitable for use in safety critical supports in swimming pools
High mechanical strength Scope for smaller diameter and hardware
Good fatigue strength Applicable for cyclically loaded assemblies
High modulus of elasticity Low propensity to stretch

S3i can manufacture wire rope assemblies and fittings in super duplex materials to order.

Please contact us with your enquiry.


Super Duplex Data Sheet download here


The British Stainless Steel Association provide this useful technical page: Duplex Stainless Steels - A Simplified Guide


Available Specifications of Duplex and Super Duplex Stainless Steel

Euro Specification: EN ASTM 1.4501 A135 F55 / US Specification: UNS S32760

Composition: Super Duplex Stainless Steel. 25% chromium super duplex (austenitic/ferritic) steel with 0.75% tungsten and copper.

Benefit: Good strength/ductility combined with high corrosion resistance.

Application: For Oil & Gas, defence, pollution control, chemical/ petrochemical and marine applications.


Euro Specification: EN ASTM 1.4462 A135 F51 / US Specification: UNS S31803

Composition: Duplex Stainless Steel. 22% chromium duplex (austenitic/ ferritic) steel (2205 type).

Benefit: Moderate/good strength and good general corrosion/ stress corrosion cracking resistance.

Application: For Oil & Gas, brewing, power generation and chemical industry applications.


Euro Specification: EN ASTM 1.4410 A135 F53 / US Specification: UNS S32750

Composition: Super Duplex Stainless Steel. 25% chromium copper-free super duplex (austenitic/ferritic) steel (also known as 2507).

Benefit: Good strength and ductility combined with high marine corrosion resistance.

Application: Primarily used for Oil & Gas and marine applications.


Euro Specification: EN ASTM 1.4507 A135 F61 / US Specification: UNS S32550 FERRINOX® 255

Composition: Super Duplex Stainless Steel. High performance 25% chromium super duplex (austenitic/ferritic) steel with 1.75% copper.

Benefit: Good strength/ductility combined with high resistance to all forms of corrosion.

Application: For Oil & Gas, defence, nuclear, chemical/petrochemical and marine applications.

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