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Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Otsuka, Satoshi; Matsuda, Yasushi*
Journal of Nuclear Science and Technology, 45(2), p.99 - 102, 2008/02
Times Cited Count：5 Percentile：34.98(Nuclear Science & Technology)The oxide dispersion strengthened (ODS) ferritic-martensitic steels are being developing for application as advanced fast reactor cladding and fusion blanket materials, in order to allow increased operation temperature. Water corrosion test of ODS ferritic-martensitic steels was conducted under a controlled alkali water environment to evaluate the water corrosion behavior, comparing to conventional 17 mass% Cr austenitic stainless steel (PNC316) and 11 mass% Cr ferritic-martensitic stainless steel (PNC-FMS). It was showed that 9Cr-ODS martensitic steel and 12Cr-ODS ferritic steel have superior water corrosion resistance, and comparable to that of PNC316 and PNC-FMS at 333K for 1,000h under varying pH of 8.4, 10, 12.
Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Otsuka, Satoshi; Matsuda, Yasushi*
JAEA-Research 2006-048, 52 Pages, 2006/07
JAEA-Research-2006-048.pdf:29.48MB
As a part of feasibility study of ODS steel cladding, its water corrosion resistance was examined under water pool condition. Although addition of Cr is effective for preventing water corrosion, excessive Cr addition leads to embrittlement due to the Cr-rich 
' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, water corrosion test was conducted for these ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1) Corrosion rate of 9Cr-ODS martensitic and 12Cr-ODS ferritic steel are significantly small and no pitting was observed. Thus, these ODS steels have superior resistance for water corrosion under the condition of 60
C and pH8
12. (2) It was showed that 9CR-ODS martensitic and 12Cr-ODS ferritic steel have comparable water corrosion resistance to that of PNC316 and PNC-FMS at 60C for 1000h under varying pH of 8, 10. Water corrosion resistance of these alloys is slightly larger than that of PNC316 and PNC-FMS at pH12 without significant differenceof appearance and uneven condition.
Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Otsuka, Satoshi; Matsuda, Yasushi*
JAEA-Research 2006-047, 100 Pages, 2006/07
JAEA-Research-2006-047.pdf:53.38MB
In a feasibility study of ODS steel cladding, its high temperature oxidation resistance was evaluated. Although addition of Cr is effective for preventing high temperature oxidation, excessively higher amount of Cr leads to embrittlement due to the Cr-rich ' precipitate formation. In the ODS steel developed by the Japan Atomic Energy Agency (JAEA), the Cr content is controlled in 9Cr-ODS martensite and 12Cr-ODS ferrite. In this study, high temperature oxidation test was conducted for ODS steels, and their results were compared with that of conventional austenitic stainless steel and ferritic-martensitic stainless steel. Following results were obtained in this study. (1)9Cr-ODS martensitic and 12Cr-ODS ferritic steel have superior high temperature oxidation resistance compared to 11mass%Cr PNC-FMS and even 17mass% SUS430 and equivalent to austenitic PNC316. (2)The superior oxidation resistance of ODS steel was attributed to earlier formation of the protective alpha-Cr
O
layer at the matrix and inner oxide scale interface. The grain size of ODS steel is finer than that of PNC-FMS, so the superior oxidation resistance of ODS steel can be attributed to the enhanced Cr-supplying rate throughout the accelerated grain boundary diffusion. Finely dispersed Y2O3 oxide particles in the ODS steel matrix may also stabilized the adherence between the protective alpha-CrO layer and the matrix.
Narita, Takeshi; Ukai, Shigeharu; Otsuka, Satoshi; Kaito, Takeji; Matsuda, Yasushi*
8th Workshop on the Ultra-Steel, 0 Pages, 2004/07
High temperature creep and oxidation tests are conducted, since the high temperature strength and oxidation resistance for the ODS ferritic steel are required for its applicability.As a result, It is identified that 9Cr-ODS martensitic steel demonstrated adquate creep strength at 973K, further titanum addition significantly improved the creep strength in 9Cr-ODS martensitic steel, and 9Cr-ODS martensitic and 12Cr-ODS ferritic steels have superior high temperature oxidation resistance compared to PNC-FMS and SUS430.
