SUPER DUPLEX STAINLESS STEELS
Super duplex steels are the top class of the duplex family. They are two-phase stainless grades in which the chromium, molybdenum and nitrogen contents have been raised so that the pitting resistance equivalent number (PREN) exceeds 40.
Both their strength and their chloride resistance are higher than those of the standard duplex steels. They show superior performance against pitting, crevice and stress corrosion cracking in hot seawater, in acidic well fluids and in chloride-bearing process environments.
Because of their high alloy content, machining and welding them demand more care, and control of phase balance and heat input during welding is critically important. Offshore platforms, seawater systems, petrochemical equipment and pump and valve bodies are the main applications.
Choosing a grade. The most widely used of the super duplex grades, AISI F53 (1.4410), is the standard choice in seawater and offshore applications. AISI F55 (1.4501), which provides additional resistance in more aggressive environments thanks to its tungsten and copper additions, is used particularly in hot seawater and acidic fluids. AISI F255 (1.4507) offers a balanced alternative between standard duplex and super duplex.
OUR SUPER DUPLEX STAINLESS STEEL GRADES
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