Fireside corrosion and steamside oxidation of 9–12%Cr martensitic steels exposed for long term testing

Abstract To obtain long term corrosion and steam oxidation data for the 9–12%Cr ferritic steels, test tube sections have been exposed in Amager 3 and Avedore 1 coal fired power plants in Denmark (formerly run by ENERGI E2). Thus direct comparisons can be made for T91 and T92 for the 9%Cr steels and X20CrMoV121 and HCM12 for the 12%Cr steels. The test tubes were welded in as part of the existing final superheaters in actual plants and exposure has been conducted over a ten year period (1994–2005). Compared to the older steel types, T92 and HCM12 utilise tungsten to improve their creep strength. From Avedore I testing, T91 and T92 can be compared for exposure times up to ∼48 000 h exposure. From Amager 3 testing, X20, HCM12 and T92 were tested; T92 has been exposed for up to 31 000 h and X20 and HCM12 have had 84 500 h exposure. Tube sections were removed for various exposure durations such that steamside oxidation and fireside corrosion could be investigated with respect to exposure time. The fireside corr...