Duplex Stainless Steel: Properties, Applications, and Selection Guide
Duplex stainless steels combine the best properties of austenitic and ferritic grades, offering high strength and excellent corrosion resistance.
What is Duplex Stainless Steel?
Duplex grades have a mixed microstructure of approximately 50% austenite and 50% ferrite, giving them a unique combination of properties.
Key Grades:
2205 (UNS S32205): The most widely used duplex grade, offering double the yield strength of 316 with similar corrosion resistance. Ideal for chemical processing, oil and gas, and marine applications.
2507 (UNS S32750): A super duplex grade with enhanced corrosion resistance and strength. Used in the most demanding environments including offshore oil and gas, desalination, and chemical processing.
2304 (UNS S32304): A lean duplex grade offering a cost-effective alternative to 316 with higher strength.
Advantages:
- High strength (approximately twice that of austenitic grades)
- Excellent corrosion resistance, particularly to stress corrosion cracking
- Good fatigue strength
- Lower alloy content for equivalent performance in many applications
Applications:
Chemical processing, oil and gas, desalination, pulp and paper, marine engineering, and structural applications requiring high strength-to-weight ratios.