Duplex & Super Duplex Stainless
High-Strength, Pitting-Resistant Stainless for Aggressive Environments
Duplex and super duplex stainless steels for chloride service, offshore platforms, desalination, and corrosive chemical processing where standard austenitic stainless is insufficient.
Why Duplex / Super Duplex
When duplex stainless is specified
Duplex stainless steels offer a two-phase microstructure (austenite + ferrite) that provides higher strength than standard austenitic grades and superior resistance to pitting and stress corrosion cracking. Super duplex grades extend performance to more aggressive chloride and acidic conditions.
Application Environments
- Chloride-containing process streams
- Offshore oil and gas platforms
- Desalination and water treatment
- Chemical and petrochemical plants
- Pulp and paper processing
- Food and beverage processing
Common Grades
2205 / UNS S31803 / S32205
Duplex
2507 / UNS S32750
Super Duplex
Ferralium 255 / UNS S32550
Zeron 100 / UNS S32760
CD3MN / CF3MN
Cast Duplex
CD3MWCuN
Cast Super Duplex
Duplex vs. Super Duplex
Standard duplex (2205) suits most chloride-containing service. Super duplex (2507, Zeron 100) is specified when higher PREN values (>40) are required for more aggressive chloride concentrations, elevated temperatures, or combined chloride and acid environments.
Compatible Processes
- Investment casting
- Sand casting
- Hot forging
- Precision CNC machining
Typical Industries
- Oil & Gas
- Petrochemical
- Desalination
- Marine
- Chemical Processing
Quality Considerations
- Phase balance testing (ferrite content)
- Corrosion test per ASTM G48 Method A
- Impact testing at low temperature
- NACE MR0175 compliance documentation
- Heat traceability and MTRs
- NDT: RT, UT, PT per applicable standards
Related
Related capabilities, industries & products
Related Capabilities
Related Industries
Working with duplex or super duplex stainless?
Submit your drawing, alloy grade, and service environment. Oakmet will review material and process fit for your application.