The paper presents the properties of the author’s company’s proprietary super duplex stainless steel. Work is presented showing the development of a more realistic laboratory solution representing typical limestone shzries found in real flue gas desulphurisation (FGD) systems. The importance of additions of metal ions such as Fe3+ and Mn24 + as well as partially oxidized sulphur species is demonstrated. Results are presented comparing the crevice corrosion resistance of super duplex stainless steel in these slurries with other commonly used wrought and cast stainless steels, for both simulated anthracite and lignite type shuries. Data from loop tests on the erosion resistance of a
range of alloys in simulated FGD slurries is presented. The results clearly show the superior resistance of super duplex stainless steel to both crevice corrosion and erosion in FGD slurries. Finally the experiences in UK FGD systems with both cast and wrought super duplex stainless steel are presented.