Cavitation Wear of T91 Ferritic-Martensitic Steel

The microstructure, hardness and cavitation wear of T91 ferritic-martensitic steel are studied and compared with some other reactor steels of the Eurofer 97 and Cr18Ni10Ti grades. It is shown that the cavitation resistance of T91 steel is 34 times higher than the cavitation resistance of Eurofer 97 steel and 11 times higher than the resistance of traditionally used Cr18Ni10Ti austenitic steel. Unlike the Eurofer 97 ferritic-martensitic steel alloyed with tungsten and tantalum, the T91 steel alloyed with molybdenum and niobium has larger prior austenite grain sizes (20 vs. 6 μm), length and width of martensitic packets (30–40 and 3–10 vs. 10–20 and 2–4 μm, respectively), and microhardness (2.47 vs. 2.07 GPa).