Some Metallurgical Observations on Fast Reactor Cladding Tubes

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青木 利昌*; 宇井 正泰*; 小山 真弘

not registered; not registered; Koyama, Masahiro

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With respect to fuel cladding tubes each for JOYO, a fast experi-mental reactor,and for FFTF in U.S.A,an examination was made mainlyon structural change in the metallography by the solution treatmentand that by heating. As a result, it was found that the solutiontreatment causes the precipitation of carbide at the grain boundary inthe case of the specimen of high carbon content, and that the graingrowth does not start until carbide went into solid solution by thesolution treatment. Observatins for recrystallization temperature in keeping heated for two hours showed that it is about 900 C for the specimen manufactured by Kobe Steel Works, about 950 C for that manufactured by Sumitomo Metal Industries, and about 800 C for that obtained from the U.S.A. Precipitates supposed to be phase were observed, keeping for 100 hours at 800 - 900 C. Moreover the solidsolubility line was drawn up for carbon, arranging the results obtained.