Joanne McIntyre - 17 September 2015
The second part of a 3-part review of duplex families and their applications takes a look at the main duplex developments since 1991.
As Jacques Charles explains in his article recently published in Stainless Steel World, in the early 1990s users of duplex gained in experience and confidence after 20 years of successful applications and technical knowledge gained through significant R&D activity. Through optimized nitrogen additions grades were easier to develop and worldwide standardization was created. As a result, significant improvements were observed in order specifications such as availability of the products including complementary products, while some key industrial players, mainly in Europe, provided significant support on both worldwide marketing and technical support through dedicated development teams.
From the 1990s onwards industrial developments enhanced the yield (e.g. reducing or suppressing the production of slivers and edge cracking) and extend the product range of duplexes including cold rolled products. Duplex stainless steels (DSS) started to be very popular worldwide for the most severe applications requiring expensive (super-) austenitic grades containing significant costly alloying additions as nickel (Ni) and molybdenum (Mo).
The 1990s also saw the development of the super duplexes. The aim of these products was to further increase corrosion resistance while simultaneously reducing sensitivity of the grade to detrimental intermetallic phases.
However the 'standard' in the world of duplex quickly became 2205. As these evolved in the early 1990s the grade began to replace 317 grades in most applications with an in-service temperature below 250C. Read the full Part 2 of Mr Charles article to learn all about how duplexes evolved to the present day. Part 1 can be viewed here.
Photo source ©HIA