Duplex alloys have always occupied something of a niche in stainless steel production, representing less than 1% (approximately 200KT) of the market. The reason for this could be the subfamily’s comparative immaturity compared to the likes of austenitic and ferritic grades of stainless steel. However, their dual-phase microstructure and relatively low density impart a broad range of desirable properties. High corrosion resistance, good tensile and yield strength relative to weight, decent formability, and more, make duplex alloys like UNS S32205 ideal for various applications in the processing and marine industries.

In this blog post, Masteel explores the properties and applications of UNS S32205 in more depth.

What is UNS S32205?

UNS S32205 is a duplex stainless steel with a mixed austenitic—ferritic microstructure, comprising a granular structure characteristic of roughly 50% each of these distinct phases. It combines the high tensile (620 MPa) and yield (450N/mm2) strengths of ferritic grades with the exceptional corrosion resistance associated with austenitic types. While it is not as easily formed as full austenitic stainless steels, it boasts a ductility and toughness far superior to ferritic steels and can be readily formed into plates ranging from extremely thin (6 – 50 mm) to fairly thick (100 – 200 mm).

Duplex steels like UNS S32205 also have a lower alloying content than many other stainless steel grades. Its chief alloying elements are chromium (22.0 – 23.0%), nickel (4.5 – 6.5%), and molybdenum (3.0 – 3.5%), which contribute towards the material’s outstanding anti-corrosive properties and stress corrosion cracking (SSC) resistivity. This low alloy content and high formability make UNS S32205 the ideal material for cost and weight savings.

Applications of UNS S32205

The cost and weight savings offered by UNS S32205 offer significant benefits for processing facilities and offshore infrastructures contending with corrosive elements. UNS S32205 steels are routinely used to fabricate pumps and valves in seawater applications, providing an exceptionally lightweight material with long-lasting resistance to seawater corrosion (chlorination, oxidation, etc.).

It is also routinely prescribed for processing applications as varied pulp mills, food processing, oil and gas piping, chemical processing, and more. Some UNS S32205 steels have also been used in emissions control components like flue gas desulfurization scrubbers, owing to the availability of thin plates with exceptional mechanical and chemical properties over extended service periods.

UNS S32205 from Masteel

Masteel is the UK’s leading supplier of UNS S32205, offering a variety of plate thicknesses to suit your application requirements. If you have any questions about when you might use UNS S32205, simply contact a member of the Masteel team today.