General characteristics    
Duplex stainless steel, also referred to as a ferritic-austenitic steel, combine many of the beneficial properties of ferritic and austenitic steels. Due to its high content of chromium and nitrogen, and often also molybdenum, this steel offer good resistance to pitting and uniform corrosion. The duplex micro-structure contributes to their high strength and high resistance to stress corrosion cracking. Duplex steels also have good weldability.  
Design features  
⇒ High strength  
⇒ High resistance to pitting corrosion, crevice  corrosion, uniform corrosion,  stress corrosion cracking and corrosion fatigue.
⇒ Good erosion and fatigue resistance
⇒ High energy absorption
⇒ Low thermal expansion
⇒ Good weldability
Corrosion resistance  
Uniform corrosion  Uniform corrosion is characterised by a uniform attack on the steel surface that has come into contact with a corrosive medium. The corrosion resistance is generally considered good if the corrosion attack is less than 0,1 mm/year. Due to the high content of chromium EN 1.4410 offers excellent corrosion resistance in many media.  
Intercrystalline corrosion  
The duplex microstructure and the low carbon content gives EN 1.4410 very good resistance to intercrystalline corrosion. The composition of the steel ensures that austenite is reformed in the heat-affected zone after welding. The risk of undesirable precipitation of carbides and nitrides in the grain boundaries is thus minimized. 
Stress corrosion cracking  
Conventional steels of the 1.4301 and 1.4401 type can be attacked by stress corrosion cracking (SCC) in chloride environments at high temperatures in combination with tensile stress. Due to their continuous ferritic phase, stainless steels of the duplex type are much less sensitive to this type of corrosion.