Duplex Stainless Steel
What is Duplex Stainless Steel?
Duplex stainless steel is an alloy that uniquely combines both austenitic and ferritic microstructures in roughly equal proportions. This dual-phase composition offers a blend of high strength, excellent toughness, and remarkable corrosion resistance, particularly against stress corrosion cracking and chloride attack.
How is Duplex Stainless Steel Made?
Duplex stainless steel began as early alloys of chromium, nickel, and molybdenum, evolving through successive generations – lean duplex, standard duplex, and super duplex grades. It manufactures duplex stainless steel by melting raw materials in electric arc furnaces, followed by Argon-Oxygen Decarburisation (AOD) to precisely control carbon and nitrogen. The addition of nitrogen boosts strength, corrosion resistance, and weldability.
A balanced mix of chromium, nickel, molybdenum, and nitrogen ensures a near-equal ferrite-austenite structure. The result:
- Twice the strength of conventional stainless steel
- Excellent resistance to pitting and stress corrosion
- High formability and weldability
After alloying, the material undergoes rolling and annealing to achieve the final mechanical properties.
Difference Between Duplex and Conventional Stainless Steel
