Extraction residue analysis on F82H-BA07 heat and other reduced activation ferritic/martensitic steels

Extraction residue analysis was conducted on reduced activation ferritic/martensitic steels, such as F82H-BA07 heat, F82H-IEA heat, JLF-1 JOYO heat and CLAM steel. M23C6 type precipitates, TaC precipitates and Fe2W Laves phase were identified in the present analyses. M23C6 precipitates were coarsened in F82H-BA07 compared with the other steels at as-normalized and tempered (NT) condition. TaC precipitate formation was enhanced in JLF-1 and CLAM compared with F82H-BA07 and F82H-IEA at as-NT condition. Laves phase were detected in F82H-IEA after aging above 550 °C, where solid solution W was significantly decreased. F82H-IEA exhibited hardening after aging at 400 and 500 °C for 100 khr, whereas softening at 600 and 650 °C. This behavior is similar to JLF-1 and CLAM, and can be understood by precipitation of TaC and Laves phase.