This paper presents an overview of duplex stainless steels (DSS) with particular emphasis on super DSS, i.e. steels containing sufficient amounts of chromium, molybdenum, and nitrogen to produce a pitting resistance equivalent greater than 40. Duplex stainless steels have an attractive combination of mechanical and corrosion properties and are thus suitable for many marine and petrochemical applications, particularly where chlorides are present. The paper covers the following aspects of DSS: physical metallurgy, mechanical properties, corrosion properties, metallurgy of welding, machinability, and applications. A large number of references to the literature are given to aid the reader who is interested in acquiring a deeper understanding of the behaviour of this family of steels.MST/1685

Super duplex stainless steels

Effect of thermal cycles on the corrosion and mechanical properties of UNS S31803 duplex stainless steel

Microstructural evolution and localized corrosion resistance of an aged superduplex stainless steel

Application of the modified electrochemical potentiodynamic reactivation method to detect susceptibility to intergranular corrosion of a newly developed lean duplex stainless steel LDX2101

The effects of partial substitution of tungsten for molybdenum on the microstructure and impact properties in 22Cr–5Ni–3Mo (wt-%) duplex stainless steel (DSS) have been investigated following aging heat treatments in the temperature range 600–1000°C. During aging the intermetallic σ and χ phases were precipitated, and the impact toughness was significantly decreased with an increase in the σ phase content. The χ phase had been precipitated on the α/γ boundary in the early stages of aging. Ferrite and χ phases in tungsten substituted duplex stainless steel contain a large amount of tungsten, and their decomposition rates are much lower compared with those in steel containing only molybdenum. Consequently, the precipitation of the σ phase is retarded in tungsten substituted DSSs, which results in high impact toughness. However, after aging for a long time, the α and χ phases transformed to the σ and austenite phases in the tungsten substituted steels, and the steels showed low impact toughness.

Effect of aging treatments on microstructure and impact properties of tungsten substituted 2205 duplex stainless steel

Very low tolerable partial pressures of H2S (pH2S) have been reported for duplex stainless steels in sour environments. However, such steels resist stress corrosion cracking (SCC) in sour ...

H. Eriksson

Papers

The applicability of duplex stainless steels in sour environments