Stainless steel round bars duplex steel 1.4462 / S31803

What is duplex stainless steel 1.4462 (S31803)?

Stainless steel round bars in grade 1.4462 are a duplex stainless-steel product commonly known in industry as duplex 2205. This grade is often referenced by several designations: EN 1.4462 (Europe), UNS S31803 (older UNS reference) and commonly compared with UNS S32205 in some sources. It combines a roughly equal mix of austenitic and ferritic microstructures, giving a balance of high strength and good corrosion resistance. Its chemistry is characterised by elevated chromium and molybdenum with added nitrogen and moderate nickel — elements that improve resistance to pitting and stress corrosion cracking.

Key properties

• High corrosion resistance — particularly to pitting and crevice corrosion in chloride-containing environments. (Pitting is localised attack that creates small holes; duplex resists this better than many austenitic grades.)
• Greater mechanical strength — duplex grades are significantly stronger than standard austenitic stainless steels such as 304 or 316, allowing slimmer and lighter designs for the same load.
• Good resistance to stress corrosion cracking — duplex steels tolerate chloride stress environments better than many austenitic types.
• Thermal behaviour — duplex steels have a lower coefficient of thermal expansion than austenitic grades and are typically suitable for service up to around 250 °C when correctly applied.
• Fabrication characteristics — 1.4462 is weldable and formable, but requires appropriate procedures (matching filler metals and controlled heat input) to preserve the duplex microstructure; it is harder to machine than common austenitic grades because of its higher strength.

Typical uses of stainless steel round bars 1.4462 / S31803

Duplex round bars are used where a combination of strength and corrosion resistance is required. Common components and applications include:

• Pump shafts, rotors and valve stems
• Shafts, fasteners and screws subject to seawater or saline environments
• Pressure vessels, pipe fittings and tanks in chemical and petrochemical plants
• Offshore and marine structures, platforms and desalination plant components
• Heat exchanger tubes and fittings in energy and process industries
• Components for the paper and pulp industry where erosive wear and corrosive fluids are present
• General engineering and manufacturing where higher strength stainless round bars reduce weight or improve durability

Who buys duplex steel 1.4462?

Typical buyers include fabricators, mechanical engineers, maintenance teams, offshore contractors, pump and valve manufacturers, and procurement specialists in the chemical, petrochemical, energy, desalination and marine industries. It is also useful for smaller engineering shops or garage-level fabricators working on corrosive or high-strength applications — provided correct welding and machining practices are followed.

Working with 1.4462 round bars — machining, welding and finishing

Machining: duplex 1.4462 machines less easily than austenitic grades because of higher strength; use sharp tooling, reduced cutting speeds and sufficient coolant.

Welding: the material is weldable but maintaining the correct austenite–ferrite balance is essential. Use appropriate filler metals and control heat input; excessive heat or improper procedures can lead to brittle intermetallic phases (such as sigma phase) which reduce toughness and corrosion resistance. Follow recognised welding procedures for duplex stainless steels.

Surface finish: round bars can be supplied in a variety of surface finishes; final corrosion resistance and appearance can be influenced by finishing and passivation treatments.

Standards, designations and ordering

This category lists duplex stainless steel round bars with the primary designation EN 1.4462 and commonly associated UNS references such as S31803 (and often discussed alongside S32205). You may also see the grade referred to informally as 2205. For specified applications ask for material certificates (e.g. EN 10204) and confirm the required mechanical and chemical test reports.

Why choose duplex 1.4462 round bars?

If you need a stainless material that offers a strong combination of corrosion resistance (especially to pitting and chloride-induced attack) and higher mechanical strength than standard austenitic stainless steels, duplex 1.4462 / S31803 round bars are an excellent choice. They allow lighter, more compact designs and perform well in demanding marine, chemical and industrial environments.

Need help selecting sizes or quantities? Check our product listings for available diameters and lengths or contact our sales team for technical advice, certified material options and cutting or machining services.